Nwamarah Uche

1

Nwamarah Uche

Digitally Signed by: Content manager’s

Name

DN : CN = Weabmaster’s name

O= University of Nigeri

Faculty of Education

DEPARTMENT OF VOCATIONAL

TEACHER EDUCATION

ANALYSIS OF MAINTENANCE ERRORS COMMITTED BY

AND ELECTRONICS TECHNICIANS IN

NIGERIA’S MANUFACTURING INDUSTRIES

NANDE, BONIFACE KWAGHKAR

PG/Ph.D/03/34708

: Content manager’s

Weabmaster’s name

O= University of Nigeria, Nsukka

Education

DEPARTMENT OF VOCATIONAL

MAINTENANCE ERRORS COMMITTED BY ELECTRICAL

AND ELECTRONICS TECHNICIANS IN

INDUSTRIES

NANDE, BONIFACE KWAGHKAR

2

CHAPTER I

INTRODUCTION

Background of the Study

The useful life of man-made things can be extended by maintenance.

Maintenance can be defined as those activities required to keep a facility in “as-

built” or as production condition and therefore continuing to have its original

productive capacity (Reason, 2000). Maintenance therefore is any activity

designed to keep machines, equipment or building in good condition and working

order. Maintenance encompasses all those activities that relate to keeping facilities

and equipment in good working order and making necessary repairs when

breakdowns occur so that the system can perform as intended (Stephenson, 1999).

Maintenance activities may include monitoring conditions of operation of

equipment, doing emergency repairs, servicing equipment, replacing worn out

parts or performing building upkeep.

In Nigeria’s manufacturing industries, maintenance activities are classified

into repairs and servicing, and are performed under two basic types of

maintenance, namely, preventive maintenance and breakdown maintenance.

Dhillon (2002) described breakdown maintenance as unscheduled maintenance or

repair to return items/equipment to a defined state, carried out because

maintenance persons or users perceived deficiencies or failures. Preventive

maintenance means care and servicing by personnel for the purpose of maintaining

Nwamarah Uche

Digitally Signed by: Content manager’s

Name

DN : CN = Weabmaster’s name

O= University of Nigeria, Nsukka

Faculty of Education

DEPARTMENT OF VOCATIONAL

TEACHER EDUCATION

ANALYSIS OF MAINTENANCE ERRORS COMMITTED BY ELECTRICAL

AND ELECTRONICS TECHNICIANS IN

NIGERIA’S MANUFACTURING INDUSTRIES

NANDE, BONIFACE KWAGHKAR

PG/Ph.D/03/34708

3

equipment and facilities in satisfactory operating condition by providing for

systematic inspection, detection, and correction of incipient failures either before

they occur or before they develop into major defects (Wikipedia, 2011). Electrical

and electronics technicians involved in preventive maintenance monitor the

equipment’s operating conditions which usually determine their actions for repairs

or servicing.

Maintenance repairs are the actions involved in fixing to its original

working condition any sort of mechanical or electrical device should it become out

of order or broken (Defense Logistica Agency, 2011). Maintenance repairs can be

defined as restoration of a broken, damaged, or failed device, equipment, part, or

property to an acceptable operating or usable condition or state (London School of

Business and Finance, 2009). Repair is carried out after failure detection and is

aimed at restoring an asset to a condition in which it can perform its intended

function. Blueprints and engineering specifications are followed during repairs to

fix equipment components; where replacement for broken or defective part is not

readily available and machine must be quickly returned to production, a sketch of

the part is made and the part fabricated in the plant machine shop.

Maintenance servicing are those activities which encompass regular

monitoring, inspection, clean up, lubrication, adjustment, alignment, calibration,

replacement, or replenishment to prolong an asset’s useful life, prevent its

breakdown and keep it capable of performing its intended function within its

design specifications (Online Business Dictionary, 2009). Maintenance servicing

activities are carried out on routine basis.

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Maintenance repairs or/and servicing performed is to preserve the proper

functioning of a physical system so that it will continue to do what it was designed

to do. Regrettably maintenance repairs or/and servicing activities performed are

not without human or maintainer errors. It is also a well-known fact that a

significantly large proportion of total human errors occur during the maintenance

phase of equipment (Dhillon & Liu, 2006).

Human error is an imbalance between what the situation requires, what the

person intends, and what he/she does (Occupational Health and Safety Agency for

Healthcare (OHSAH), 2004). Dhillon and Liu (2006) defined human error as the

failure to perform a specified task or perform a forbidden action that could lead to

disruption of scheduled operations or result in damage to property and equipment.

Human error in maintenance is a mistake made by a person rather than being

caused by a poorly designed process or the malfunctioning of a machine. Errors

committed during maintenance work which produce unintended results such as

unwanted time delay, difficulty, problem, incident, malfunction or failure during or

shortly after equipment start-up or in use may be known as maintenance errors.

Maintenance error therefore is a form of human error. Its scope is vast.

Maintenance errors range from becoming distracted and forgetting important

checks to knowingly deviating from a permit to work procedure in order to save

time or to get the job done in unexpected circumstances (Mason, 2009). Specific

maintenance errors committed include among others: non-detection of problem

states (McCormick & Tiffin, 1979; and Dunn, 2007); bridging neutral and live or

positive and negative wires (National Electric Power Authority (NEPA) then, now

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Power Holding of Nigeria (PHON), 1991); forgetting under time pressure to fix

back some bolts and nuts (Parliamentary Office of Science and Technology, 2001)

and not following safety rules and procedures (Nigerian Institute of Safety

Professional, 2004). According to Dunn (2007), more than half of errors in

maintenance are recognized as having happened before – often many times.

Dunn (2007) and Reason (1990) classified the maintenance errors into

following types: namely, recognition failures, memory failures, skill-based slips,

rule-based mistakes, knowledge-based errors and violations. Recognition failures

are acts of improper identification and detection of objects while memory failures

are incorrect acts which indicate bits of needed materials were forgotten (Dunn,

2007). In slips and lapses, what is to be achieved is known yet simple errors are

made in the actions due perhaps to distraction or lose of concentration (Mason

2009). In mistakes, work procedure may be forgotten or never fully understood

and a wrong decision is made during a procedure with some novelty. A violation is

an intentional deviation from procedures or practices, for example, non-compliant

actions that have become normal, performed necessarily in order to get a job done

(Schreiber, 2007).

Maintenance errors are caused. Reason and Hobbs (2003) identified situation

and a mental state to be responsible for errors in maintenance in industry.

According to McCormick and Tiffin (1979), situational variables include

workplace and equipment layout, environment, design of machinery hand tools

and other equipment, methods of handling, transporting, storing and inspecting the

equipment, job planning information and its transmission and operating

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conditions; while mental or individual variables cover factors as attitudes,

personality, physical skills, age, sex, education and experience. Reason and Hobbs

(2003) viewed errors in maintenance as product of chain of actions and conditions

which involve people, teams, tasks, workplace and organizational factors.

Managers of manufacturing industries consider their maintenance operations

to be of high standard; quality performance, equipment failures and safety

incidents frequently reveal causes for concern (Dhillon, 2002). Many of these

incidents and failures are associated with maintenance errors. Error of non-

detection of problem states at material time due to inadequate experience and skills

caused alternating current (AC) motors to burn and hence breakdown of equipment

in Benue Breweries’ water pumping system (Patni, 2008), in Nigerian National

Petroleum Corporation (NNPC)’s fuel pumping system (Lukman, 2002), in

Ashaka Cement factory’s packing plant in 1985 (Kime, 2008). Errors of improper

isolation and not following safety rules due to “mind set” caused splash resulting

to skin burn and damage to equipment at Ashaka cement factory (Kime, 2008).

Between 1986 and 1997 a total of 3,183 injuries in Nigerian factories were

reported, of which 71 were fatal (Ezenwa, 2001). In addition to injuries

maintenance errors pose significant financial burdens on manufacturing industries

in terms of breakdowns. The impact of human error in maintenance or

maintenance error on maintenance quality and costs, safety and equipment

reliability is huge (Dunn, 2007); and therefore, demands a real obligation to try to

prevent in manufacturing industries the likelihood of all causes of errors in

maintenance activities.

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Analysis of maintenance errors committed by electrical and electronics

technicians in Nigeria’s manufacturing industries is one way to develop a better

understanding of errors in maintenance activities and to develop better tools and

techniques to avoid or minimize their consequences in Nigeria’s manufacturing

industries. Analysis is the process of breaking a complex topic or substance into

smaller parts to gain better understanding of it (Wikipedia, 2011). Analysis is also

the separation of an intellectual or material whole into its constituent parts for

individual study (The American Heritage, 2002). Analysis of maintenance errors

committed by electrical and electronics technicians means breaking down

maintenance errors, identifying the types and causes, and providing preventive

strategies to be applied in any maintenance actions on electrical and electronic

devices and instruments in manufacturing industries.

Manufacturing industry refers to any facility devoted to the conversion of

raw materials into marketable products. The production system of the

manufacturing industry is automated. Electrical machines for example, provide

forces and torques to generate motions in countless industrial applications

(Rizzoni, 2004). Electronics equipment provides control system to detect and

measure variables or conditions of operating equipment (Bryan, 1978). This

automation has not only increased productivity level of the industries but also

increased the number of jobs including monitoring which leads to fatigue, its

resulting errors with their adverse effects including accidents and equipment

failure (Reason, 1990). Okonkwo (1997) expressed that in a complete electrical

and/or electronic system failure of one among thousands of components may be

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catastrophic. The electrical and electronics equipment in Nigeria’s manufacturing

industries therefore require high reliability and effective maintenance by skilled

maintenance personnel which may include qualified electrical and electronics

technicians.

According to the Council for Regulation of Engineering of Nigeria (COREN)

(1992 amended) qualified electrical and electronics technician must possess the

specified qualifications of engineering technicians which are as follows: National

Diploma (ND) or Full Technological Certificate (FTC) - technician qualification;

or Higher Professional Diploma in Engineering and Technical Certificate as part of

an approved apprenticeship. In addition years of relevant work experiences are an

advantage for employment in various types of manufacturing industries.

Qualified electrical and electronics technicians employed with other

maintenance personnel in manufacturing industries carry out under supervision

maintenance tasks in their respective disciplines on manufacturing equipment.

Many times during maintenance work, accident occurs or after maintenance

activities have been performed, equipment fails during or shortly after start-up

(Kirn, Noland & Hauber, 2007) as a result of errors (Mather, 2004). Almost on a

daily basis various degrees of industrial accidents are recorded from minor to

major injuries to employees in Nigeria (Da Vinci, 2009). Charles-Owaba and

Adebiyi (2009) identified the injuries in Nigeria’s manufacturing industries as

trivial wounds, minor, serious, and fatal injuries. The devastating effects of

maintenance errors and economic losses sustained during industry breakdown

make it necessary that maintenance errors committed by electrical and electronics

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technicians on electrical and electronics equipment which play key and dominant

role of providing complete automation of Nigeria’s manufacturing industries be

studied and analyzed so that causes can be identified and possible occurrence

reduced or eliminated.

Statement of the Problem

Maintenance crew including electrical and electronics technicians spend

hours to retain or/and restore the original working conditions of manufacturing

equipment so that the manufacturing industry can perform as intended. Numerous

research studies have shown that over fifty percent of all equipment fails

prematurely after maintenance work has been performed on it (Dunn, 2007). He

further stressed that in the most embarrassing cases the maintenance works

performed were intended to prevent the very failures that occurred. Mason (2009)

explained that maintenance errors can impact on safety and performance in a

number of ways: poor repairs for example, can increase the amount of breakdowns

which in turn can increase the risk associated with equipment failure and personal

accidents.

Equipment failures as a result of maintenance errors have been a worrisome

problem in recent times in Nigeria’s manufacturing industries. Anyanwu (1997)

observed that frequent machine breakdown caused decline in manufacturing share

in Gross Domestic Product (GDP) between 1992 and 1995. Recently equipment

failures as a result of maintenance errors caused oil spill which resulted into

environmental degradation in the Niger delta (Okonji, 2009). Felton (2001)

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observed that equipment failure is the leading cause of accident. Accidents as a

result of maintenance errors lead to loss of lives or limbs in manufacturing

industries. In his study on fatal injuries between 1986 and 1997 in Nigerian

factories, Ezenwa (2001) reported a total of 3,183 injuries, out of which 71 were

fatal.

Maintenance errors have caused losses in the past and will continue to cause

in future if not identified and corrected (Kirn, Hauber & Noland, 2007). The losses

in manufacturing industries raise question. Clearly put what damages and injuries

are caused by known types of maintenance errors committed by electrical and

electronics technicians in Nigeria’s manufacturing industries? Identifying the

causes and types of maintenance errors committed by electrical and electronics

technicians, and providing preventive and eliminative measures to manufacturing

industries if implemented will boost the economic stability and reduce health

hazards associated with maintenance errors.

Purpose of the Study

The purpose of the study is to analyze known types of maintenance errors

committed by electrical and electronics technicians in Nigeria’s manufacturing

industries. Specifically, the objectives of the study are to:

1. Identify likely causes of maintenance errors committed by electrical and

electronics technicians in Nigeria’s manufacturing industries.

2. Determine how often maintenance errors occur in repair processes in

Nigeria’s manufacturing industries.

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3. Determine how often maintenance errors occur in servicing processes in

Nigeria’s manufacturing industries.

4. Find out the levels of accidents caused by known types of maintenance errors

committed by electrical and electronics technicians in Nigeria’s

manufacturing industries.

5. Find out the levels of equipment failures caused by known types of

maintenance errors committed by electrical and electronics technicians in

Nigeria’s manufacturing industries and;

6. Determine strategies for reducing or eliminating maintenance errors in

Nigeria’s manufacturing industries.

Research Questions

The following research questions are framed to guide the conduct of the study:

1. What are the likely causes of maintenance errors committed by electrical

and electronics technicians in Nigeria’s manufacturing industries?

2. How often do maintenance errors occur during repair processes in Nigeria’s

manufacturing industries?

3. How often do maintenance errors occur during servicing processes in

Nigeria’s manufacturing industries?

4. What levels of accidents are caused by known types of maintenance errors

committed by electrical and electronics technicians in Nigeria’s

manufacturing industries?

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5. What levels of equipment failures are caused by known types of

maintenance errors committed by electrical and electronics technicians in

Nigeria’s manufacturing industries?

6. What are the strategies to be employed in reducing or eliminating

maintenance errors in Nigeria’s manufacturing industries?

Hypotheses

The following null hypotheses are formulated and were tested at 0.05 alpha

levels.

HO1: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on the likely causes of maintenance

errors in Nigeria are manufacturing industries.

HO2: There is no significant difference in the mean responses of supervisors and

electrical and electronics technicians on how often errors occur during repair

processes in Nigeria’s manufacturing industries.

HO3: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on how often errors occur in servicing

processes in Nigeria’s manufacturing industries.

HO4: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on levels of accidents caused by known

types of maintenance errors in Nigeria are manufacturing industries.

HO5: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on levels of equipment breakdowns

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caused by known types of maintenance errors in Nigeria are manufacturing

industries.

HO6: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on the strategies for reducing or

eliminating maintenance errors in Nigeria are manufacturing industries.

Significance of the Study

Manufacturing industries contribute to economic development of the nation

and socioeconomic well being of individuals. As a result, the findings of this study

will be significant to manufacturers, shareholders, the government and the society,

institutions of learning, electrical and electronics technicians and industrial

psychologists. The findings of the study will be conveyed to the concerned

individuals through workshops, seminars, conferences and appropriate means such

as meeting to create awareness of the types, causes and consequences of errors in

the Nigeria’s manufacturing industries. The findings of the study on maintenance

errors committed by electrical and electronics maintenance technicians in

Nigeria’s manufacturing industries will be used to retrain maintenance personnel

who are directly involved in preventing and committing errors. It is hoped that the

findings from the study will sensitize manufacturers to retrain the maintenance

personnel for effectiveness and efficiency of manufacturing industries; it is also

hoped that through counselling the findings of the study will enable electrical and

electronics maintenance technicians among maintenance personnel internalize the

nature of errors committed during maintenance activities. The internalization of

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maintenance errors will enable electrical and electronics maintenance technicians

to avoid errors in order not to be injured or cause damage to equipment; and this in

turn will help manufacturers to spend less on maintenance precisely accidents and

spare parts.

The findings of the study will guide the society in that electrical and

electronics technicians who are members of the society will be trained on error

reduction; the knowledge acquired from training will result to less accidents and in

turn less dependants or injured persons for society to care, also an effective error

reduction implies improved efficiency, hence quality products for the society to

use.

The findings from the study will guide the government to make policies

which will encourage or enforce error investigation, error reporting and error

documentation (for feedback) as an integral means to intensify workforce

awareness of maintenance errors meant to bring improved efficiency and

profitability in manufacturing industries. With improved efficiency and higher

profitability government will receive higher tax to use to improve the welfare of

her people.

The findings from the study will sensitize the shareholders to be responsive

to the required needs of manufacturing industries. Provision of the required needs

will promote effectiveness and improve efficiency of manufacturing industries.

The improved efficiency of manufacturing industries will result into increased

dividends and higher profitability and interest rates for the shareholders to enjoy.

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The findings from the study will provide the framework for raising workforce

awareness on maintenance errors which industrial psychologists will find useful.

The findings of the study will equip industrial psychologists to effectively counsel

technicians to recognize their limitations and to be able to overcome the problems

associated with maintenance errors. Through the effective counselling on error

reduction the role of industrial psychologists will be highly appreciated for

improving effectiveness and efficiency of manufacturing industries.

The findings from the study will form framework which institutions of

learning will use in developing programmes on human error (reduction)

management in maintenance for improvement of practical skills. The findings of

the study on maintenance errors reduction (management) if implemented in

institutions of learning will go a long way in helping students during training

acquire skills necessary for maintenance practice in manufacturing industries.

Scope of the Study

The study of analysis of maintenance errors covers all manufacturing

industries in Nigeria. It focuses on maintenance activities carried out by electrical

and electronic technicians in manufacturing industries.

The study concentrated on: maintenance errors and their classifications in

maintenance activities; errors committed in maintenance phase of equipment are

process errors and maintainer errors. However process errors which are usually

caused by a poorly designed process or the malfunctioning of a machine and not

mistakes made by a person are not included in this study of analysis of

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maintenance errors committed by electrical and electronics technicians in

Nigeria’s manufacturing industries. The study also focuses on how often errors are

committed. Furthermore, the study concentrated on effects of maintenance errors

which include levels of accidents and equipment failures. Finally the study

concentrated on contributing factors to maintenance errors such as management

failures, human characteristics and working environments, physiological and

psychological factors

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CHAPTER II

REVIEW OF RELATED LITERATURE

This chapter on review of related literature is treated under the following sub-

headings.

1. Conceptual Framework of Maintenance errors

• Errors and types of errors committed in maintenance activities

• Causes of maintenance errors committed

• Frequency of recurrences of maintenance errors

• Effects of maintenance errors

2. Theoretical Framework of Maintenance errors

3. Empirical studies Relevant to the study of Maintenance errors

4. Summary of Review of Related Literature

Conceptual Framework of Maintenance errors

Conceptual framework is a description of maintenance errors which result

from maintenance activities of repairs and servicing carried out by electrical and

electronic technicians, and which lead to levels of accidents and equipment failures

in Nigeria’s manufacturing industries. The Conceptual framework of maintenance

errors as presented in a schematic form in figure 1 is structured on the specific

objectives of the purpose of the study.

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Effects: Levels of accidents and equipment failures

Figure 1 Conceptual Framework of study of Maintenance errors

Conceptual framework comprises maintenance errors and types of

maintenance errors, qualifications of electrical and electronics technicians, causes

of maintenance errors, oftenness of recurrences of errors, and effects of

maintenance errors covering levels of equipment failures and accidents. These

areas mentioned form sub-headings to descriptions of conceptual framework of

maintenance errors

Errors and types of errors committed in maintenance activities:

No one is immune to error (Dunn, 2007). Electrical and electronics

maintenance technicians inclusive commit errors in maintenance activities in

Nigeria’s manufacturing industries. It is also a well-known fact that a significantly

large proportion of total human errors occur during the maintenance phase of

equipment (Dhillon & Liu, 2006). Human error is an imbalance between what the

Maintenance errors

Causes of maintenance errors

Types of maintenance errors

Oftenness of errors Qualification of electrical and electronics technicians

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situation requires, what the person intends, and what he/she does (Occupational

Health and Safety Agency for Healthcare (OHSAH), 2004). Reason (1990) defined

human error as a generic term to encompass all occasions in which a planned

sequence of mental or physical activity fails to achieve its intended outcome.

Peters (1962) proposed a definition of human error in relation to maintenance as a

deviation from previously established, required or expected standard of human

performance that results in an unwanted or undesirable time delay, difficulty,

problem, incident, malfunction or failure. Dhillon & Liu (2006) defined human

error as the failure to perform a specified task (or the performance of a forbidden

action) that could lead to disruption of scheduled operations or result in damage to

property and equipment. Human error with respect to maintenance is a mistake

made by a person rather than being caused by a poorly designed process or the

malfunctioning of a machine, for example, a computer. Human error may be

referred to as an act, assertion or function that unintentionally deviates from what

is correct, right or true.

Error committed in maintenance activities is the measurement counterpart

of reliability, and most, if not all, errors can be classified at some stages as human

errors (Kara & Collin, 1992). According to Hollnagel (2005), human error has at

least three different denotations, so that it can mean either the cause of something,

the event itself (the action), or the outcome of the action.

Humans error as cause: The oil spill was caused by human error. Here the focus is

on the action (the human error) as the alleged cause of the observed outcome (the

oil spill).

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Human error as event or action: I forgot to check the water level. Here the focus is

on action or process itself, whereas the outcome or the consequence is not

considered. In some cases the outcome may not yet have occurred but the person

may feel that an error has been made, such as having forgotten to do something.

Nevertheless, a forgotten item or action need not always lead directly to a manifest

failure.

Human error as consequence: I made the error of putting salt in the coffee. Here

the focus is on the outcome, although the linguistic description is of the action. In

this example, the fact that the coffee becomes undrinkable is the matter of concern

and the action is therefore equated with the consequence.

In practice, people may often realize consciously or subconsciously that

something has gone awry before the consequences have had time to manifest

themselves and therefore make attempts to compensate for or adjust the

development of events. According to Hollnagel (2005), following the proposal of

Amalberti (1996) this leads to the following classification:

• Actions for which the actual outcome matches the intended outcome,

that is, actions that seem to achieve their goal. These actions are usually

regarded as correctly performed actions, hence give the cause for

concern, even though it is possible that the outcome came about in other

ways.

• Actions that are perceived as having been carried out incorrectly in

some ways, but where the discrepancy is detected and corrected. This

can either happen as the action is being carried out, where typing

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mistakes are typical example, or immediately after as long as the system

makes a recovery possible. If the system is sufficiently forgiving, the

actual and intended outcomes may still match and the action may

therefore for all intents and purposes be considered as correct.

• Actions which are recognized as being carried out incorrectly, and

where recovery is not possible. A recovery can be impossible for several

reasons, for instance that the system has entered an irreversible state,

that there is insufficient time or resources, etc. In these cases the actual

and intended outcomes do not match, and the action is therefore

characterized as an error.

• Actions that are recognized as being carried out incorrectly, but where

the discrepancies are ignored. This usually happens because the person

considers the expected consequences of the action failure as unimportant

in an absolute or relative sense. This assessment may either be correct or

incorrect, depending among other things on the users’ knowledge of the

system in question. If it turns out that the consequences were not

negligible, the action is in retrospect classified as an error.

• Actions that are carried out incorrectly, but which are not detected at the

time, and therefore not recovered. The action is therefore characterized

as an error.

It follows from the description above that the common element is the

detection or recognition that the outcome differs from what is expected. The brain

makes some kind of comparison between actual and intended outcomes on a neural

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level. This enables human beings to be quite good at detecting when something has

gone wrong. In conclusion, human performance is always variable. Sometimes the

variability becomes so glaring that it leads to unexpected and unwanted

consequences, which then are called errors.

Errors may be characterized in terms of behaviour components that reflect

the basic type of human behaviour that generate them. According to McCormick

and Tiffin (1979), errors made by human beings are classified as follows:

• Input behaviour (errors of sensory or perceptual input);

• Mediator errors (errors of some mediation or information processing

type)

• Output errors (errors in making physical response)

. According to Wikipedia (2009), there are many ways to categorize human error.

• exogenous versus endogenous (for example, originating outside versus

inside the individual)

• situation assessment versus response planning and related distinctions in

o errors in problem detection

o errors in problem diagnosis

o errors in action planning and execution (for example: slips or errors of

execution versus mistakes or errors of intention)

• By level of analysis; for example, perceptual (e.g., optical illusions versus

cognitive versus communication versus organization

Human erro6rs are prevalent in maintenance activities. Pennie, Brook and

Gibson (2007) noted that James Reason, a leading authority on human error,

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commented that if an evil genius was given the job of creating an activity

guaranteed to produce an abundance of errors they would devise something akin to

maintenance work. Errors which occur in the maintenance processes meant to

restore or retain industrial equipment to their original working conditions may be

called maintenance errors. Maintenance errors are discrete form of human error

(Dhillon 2002). A maintenance error is the failure of a maintenance system

(including people) to perform in the manner expected (Franklin, 2008).

Maintenance errors are the product of a chain of actions and conditions, which

involve people, teams, tasks, workplace and organizational factors (Reason and

Hobbs, 2003). Dunn (2007) explained that more than half of maintenance errors

are recognized as having happened before-often many times.

Reason (1993) and Dunn (2007) classified human errors which occur in

maintenance activities according to their contributing factors as follows:

Recognition Failures: these include:

• Misidentification of objects, signals, and messages; and

• Non-detection of problem states.

Memory Failures: these include:

• Input failure – insufficient attention is paid to the to-be remembered

item. This in turn can include:

a. losing our place in a series of actions;

b. time gaps experience.

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• Storage failure – to-be remembered materials decay or suffer

interference. Most common in maintenance is the problem of forgetting

the intention to do something.

• Output failures - when we cannot recall at the required time such as the

name of something-being an experience.

• Omission following interruptions - we rejoin a sequence of actions

having omitted certain required steps.

• Premature exists - we terminate a job before all actions are complete.

Skill-based slips: Slips are errors which occur during the performance of

simple, routine actions. They include cases where workers tripped, fumbled

objects or carried out an automatic action in a familiar situation when they did not

intend to perform the action in the manner they did (Hobbs, 2005). Dunn (2007)

stated that skill–based slips are generally associated with automatic routine, these

can include:

• Branching errors - such as intending to drive out on sight-seeing on

weekend but missing the turnoff, and continuing on towards the office

as you would every other day of the week

• Overshoot errors - intending to stop at the market on the way home, but

forgetting and continuing home without stopping.

Skill-based Attention Slips Memory Lapses - may involve the unintentional

deviation of actions from what may have been a perfectly good plan (Reason

1993). We are all prone to these types of errors and to recognize when we have

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slipped up, quite often in the immediacy of the event. For example, putting the

butter in the oven instead of the fridge; making a cup of tea instead of coffee;

picking up the wrong syringe; selecting the wrong person in an email distribution

list. Errors caused by distraction and interruption are generally difficult to

eliminate completely but it is possible to control and prevent them.

Mistakes occur when actions follow a plan, but the plan deviates from the

intended path to the desired goal. These errors occur when people do not have

appropriate or sufficient information upon which to base their decisions or plans.

They also occur where people do not understand the rules they are working within,

or misapply the information because of lack of experience or knowledge (Reason,

1993). There are therefore two principal types of mistakes.

Rule-based mistakes: According to Hobbs (2005), rule based-errors can

occur when a person is working in a familiar environment but where they fail to

take into account circumstances which could have been apparent at the time. As a

result their actions result in unintended consequences. Rule based-errors do not

necessarily involve an intentional violation of procedures but rather indicate that

the person failed to apply unspoken rules of good practice to their work. Common

forms of rule errors are untested assumptions or failures to check systems before

acting. Dunn (2007) observed that maintenance work is highly proceduralized and

full of rules. These can be written or exist only in peoples’ heads. Rule based

errors include:

• Misapplying a good rule - that is using a rule in a situation where it is

not appropriate;

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• Applying a bad rule - the rule may get the job done in certain situations,

but can have unwanted consequences. This is the most common when

people pick up others’ bad habits.

Knowledge-based errors: These are mistakes in which the individual encounters

a novel situation for which his/her training does not provide some pre-learned rule-

based solution. The consequence is therefore that he/she has to use ad-hoc “on

line” reasoning based upon his/her experience to date. Due to this lack of

experience, he or she will have an incomplete or incorrect mental model of the

problem (Reason, 1993). Generally, Knowledge-based error is the situation when

someone is performing an unusual task for the first time. Knowledge based-errors

are strongly associated with inadequate training (Hobbs, 2005).

Violations: These are deliberate acts which violate procedures. They involve

deliberate deviations from some regulated code of practice or procedure (Reason,

1993). They occur because people intentionally break the rules. Most violations

appear to be well-intended attempts to complete a task in the face of time pressures

or other challenges (Hobbs, 2005). Nigerian institute of Safety Professionals

(2004) enumerated types of violations to include:

• Unintentional violations: Understanding-people do not know how to

apply the procedures. The problems with understanding may arise from

the use of difficult language in procedures, many cross-references and a

general failure to consider the level of users when designing and writing

the procedures.

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• Unintentional violations: Awareness-people act as if there is no

procedure

• Routine violations: Rules are broken, because they are felt to be

irrelevant or because people no longer appreciate the dangers involved.

Routine violations occur when the effort of rule following is felt to be

greater than apparent benefits. Jobs may be perceived as having little

risk, when done by a skilled person, or the procedures may be felt to be

unnecessary, even by a well-intentioned and motivated workforce.

Unless control is exercised, a culture that tolerates violations is created.

• Situational violations (No-can-Do): It is impossible to get job done by

following the procedures strictly. Some violations occur when to

understand real working conditions may increase pressure to violate in

order to get the job done and achieve targets.

• Optimizing violations (I-can-Do-Better): It is sometimes possible to get

the job done faster, more conveniently or have a thrill by not adhering to

the rules. Incentives, such as bonus for meeting targets or achieving

personal goals, may encourage optimizing violations. It should be noted

that such violations can serve as the basis for improvements in

productivity and safety if brought out into the open, communicated,

discussed and approved.

• Exceptional violations: People have to solve problems for the first time

and fail to follow good practice. In new situations where there may be

28

no procedural guidelines, this kind of violation may occur such as in

jobs that require a great deal of novel problem solving. It is competence,

rather than procedures, that will help to reduce the occurrence of rare,

yet dangerous violations.

Altman (1964) stated that errors are differentiated in relation to three general

types of work activities. They are:

Work involving discrete acts:

• Omissions (failure to perform a required action)

• Insertions (performance of a non-required action)

• Sequence (performance of actions out of sequence or at wrong time)

• Unacceptable performance (usually unacceptable quality)

Continuous actions: (as in continuous control of a process)

• Failure to achieve end state in available time

• Failure to maintain desirable degree of control

Monitoring (vigilance) function

• Failure to detect relevant stimuli or signals

• False detection of stimuli or signals

McCormick and Tiffin (1979) explained that it is frequently difficult to

isolate the real cause of specific errors. However the authors attributed errors to

situational and individual variables. Situational variables include workspace and

equipment layouts; environment; design of machinery hands tools, and other

equipment, methods of handling, transporting, storing and inspecting the

29

equipment; job planning information and its transmission; and operating

conditions. McCormick and Tiffin (1979) explained that individual variables are

attitudes, personality, physical skills, age, sex education and experience. Ware in

McCormick and Tiffin (1979) pointed out that both types of variables mediate

human performance that is; they do not control performance directly. The

situational variables provide framework within which the individual variables

operate.

Errors affect the quality of work people do, and can contribute to injuries

and fatalities. Some workmanship errors of course can be perceived readily either

by direct observation or from subsequent consequences (McCormick & Tiffin,

1979). Such subsequent consequences from maintenance of production equipment

in manufacturing industries are economic. This is quite contrary to the goal of

maintenance as stated by Stephenson (1999), to keep the production system in

good working order at minimum cost.

Maintenance is any action that retains working system in a satisfactory

operational condition and if a failure occurs restores the failed system to a

satisfactory operational condition (Bacon, 1989). The British Standards Institution

(BSI, 1984) defines maintenance as a combination of all technical and associated

administrative activities required to keep equipment, installations and other

physical assets in the desired operating condition or restore them to this condition.

Maintenance is also any activity designed to keep equipment or asserts in working

condition (Monk, 1982). Stephenson (1999) expressed that maintenance activities

are often organized in two categories namely; (i) building and grounds and (ii)

30

equipment maintenance. Building and grounds, is responsible for appearance and

functioning of buildings, parking lots, lawns, fences, and the like. Equipment

maintenance entails keeping machinery and equipment in good and working order.

The mechanization and automation of manufacturing industries have

increased the number of maintenance jobs in which the major functions is that of

monitoring an operation of equipment or process. The primary concern for

technicians in monitoring is the correct identification of all, or most of the events

that should require their actions such as calibration, services and repairs.

1. Monitoring

Monitoring is to watch and check production equipment over a period of time

in order to see how it operates so that necessary actions can be taken should

changes in conditions of operations are perceived. Monitoring may be referred to

as intensive care of operating equipment for twenty-four hours in manufacturing

industry. Monitoring is carried out either continuously or at periodic intervals,

depending on the plant equipment being monitored. “Plant and equipment that are

required to run for a pre-determined period over many weeks would require

continuous monitoring whereas equipment for example a heating pump or motor

unit fitted with sealed bearings and a mechanical seal on the pump elements would

require periodic monitoring (Snow, 1991).

Plant and equipment include generators, electrical machines and electronic

equipment which provide complete automation of each manufacturing industry.

Wickens and Holland (2000) explained that automation describes a way of

31

completing work through the use of mechanical and electrical devices (electrical

machines and equipment) rather than through direct human action. Electrical

machines and equipment are classified in terms of their energy conversion

characteristics. Stephen (1993) and Rizzoni (2004) explained that a machine acts

as a generator if it converts mechanical energy from prime mover say, an internal

combustion engine to electrical form. A machine can be classified as a motor if it

converts electrical energy to mechanical form. Electrical motors provide forces

and torques to generate motions in countless industrial applications for example,

machines tools, robots, punches, presses and propulsion systems of electric

vehicles (Rizzoni, 2004). Generators are used in power generating plants or the

common automotive alternator.

Control equipment are electronics equipment which provide the control

system to detect, measure the variables or conditions of the operating equipment

and machines. Control systems refer to methods of adjusting the flow of energy

from a source to a load or process so that some desired results may be achieved

(Bryan, 1978). With advent of modern technology more products and machines are

embedded with sensors and connected through tethered-and-tethered networks

(Lee, 2007).

Electrical and electronics technicians are seconded to equipment or placed on

designated locations to monitor the equipment’s conditions on on-load and off-

load modes. On load monitoring is carried out without interrupting the operation of

the unit of production; and off-load monitoring is carried out when the unit is shut

down or at least removed from its prime duties (Okah-Avae, 1996). According to

32

Lee (2007), machine conditions are constantly monitored and their signatures

evaluated. However, this is done at machine level -one machine at a time. Some

locations of the equipment being monitored may expose electrical and electronics

technicians to heat, grease and noise on factory floor. Some have to work in cramp

spaces (Fullerton, 1996).

There are a variety of monitoring methods. “The suitability of particular

method could be determined by the age, type and operating condition of the

machinery under consideration; but more importantly, by its ability to give

information on the general mechanical health or any particular mechanical ailment

of the machinery” (Okah-Avae, 1996). There are general purpose methods and

specialized methods. Okah-Avae (1996) and Snow (1991) enumerated the

monitoring methods for general-purpose methods to include: Vibration

monitoring, Sound monitoring, Lubricant monitoring, Thermal monitoring,

Corrosion monitoring, Acoustic emission monitoring and Environmental

monitoring.

The specialized methods as compiled by Okah-Avae (1996) are: Ultrasonic

measurements, Shock pulse measurements, Strain load measurements, Flux

monitoring and Industrial computers. Both the general purpose and specialized

methods are used in on-load and off-load monitoring modes. Only vibration testing

that is carried out on off-load mode of monitoring. The machines, test equipment

and instrument after being installed in the manufacturing industries are maintained

by among others electrical and electronics maintenance technicians.

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Vibration Monitoring: A change in the physical or running condition of

mechanical system usually gives rise to a corresponding change in the vibration

produced by them. Signals which result from vibrations are usually combination of

sinusoidal, periodic and random signals. “Pure sinusoidal signals are those which

have only one frequency component Okah-Avae, (1996). A periodic signal is one,

which contains many discrete frequency components, super-imposed on each other

and usually having dominating frequency; and random signals have non discrete

frequency spread, which is continuous over a wide range. They never repeat

themselves (Okah-Avae, 1996).

Electronics equipment such as vibration monitors are built into the

monitoring system controlling the item of plant. This provides an earlier warning

of any deterioration in bearings, gear damage and wear, valve leaks, imbalance of

rotating parts, misalignment or effects caused by incorrect displacement of fluids.

Operators have to identify the warning signals and report for appropriate actions.

There are also hand held vibration monitors used for periodic checks on a wide

variety of plant and equipment (Snow, 1991). Global spec (1999-2007) has

vibration test equipment and instrument, which include instruments, equipment

and sensors for measuring, transmitting, producing, controlling and or analyzing

vibration, frequency shock and sinusoidal or oscillatory motion. Electrical and

electronics maintenance technicians observe signals and work on control

equipment which detect vibration signals generated and report to respective

mechanical maintenance personnel for appropriate action.

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Sound Monitoring: Relative positions of the sources of sound and their directions

of propagation vis-à-vis the sensors are major consideration in sound monitoring.

Various characteristics which determine the finality and nature of sound include

speed, pressure level, frequency, power and intensity. “Sound pressure level (SPL)

is measured in decibels (dB) (SPL=10log10 P/p0 dB) and it is directly related to the

loudness of the sound. Another useful measure of sounds is the power level (SWL)

(SWL=10log10 w/w0 dB) which is directly related to the square of the pressure.

Sound sensors are installed in or around equipment that develops sound problems

such as gear trains bearings, pumps and compressors diesel and jet engines and

hydraulic values. Electrical and electronics technicians maintain sound monitoring

equipment and solve electrical machine sound related problems.

Lubricant Monitoring: Lubricant monitoring is done in order to detect, at the

earliest possible, any condition likely to cause machinery breakdown. Lubricants

reduce friction hence wear of two surfaces that are moving relative to each other.

Liquid lubricants effect some cooling of moving parts as well as carry away dirt,

moisture and foreign materials between the sliding surfaces. Component wear

leads to component deterioration and hence machinery failure (Okah-Avae, 1996).

Traces of wear from moving parts are therefore identified with the use of the

instrument. Fluid condition monitor monitors the built up of ferromagnetic wear

debris in samples of lubrication and hydraulic oils (Snow, 1991). Other

instruments used in lubricant monitoring include: Rotary particle depositor (RPD),

magnetic chip detector (MCD) and spectrometer. Limits of wear element

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concentration levels are established based on normal and allowable concentration

data. Electrical and electronics maintenance technicians observe signals and work

on control equipment which detect dirt, moisture and foreign materials between

moving faces or/and report to respective mechanical maintenance personnel for

appropriate action.

Thermal Monitoring: Numerous machinery faults or equipment malfunctions

give rise to increased temperature of the equipment surface. In some cases heat

generated is transmitted to the surface from hot bearing or a worn out furnace wall.

Temperature meters in form of infrared camera enable the operative to take

readings from a distance; there are electrical deflecting instrument which receive

signals from resistance thermometer, thermocouples, thermopile or other radiation

pyrometer.

Likely sources of thermal effects are: Motor overload or electrical fault, damaged

electrical components, bearings with poor lubrication, internal damage, overload or

misalignment and transmission components with poor lubrication, overload or

incorrect assembly.

Thermal monitoring in form of thermal imaging has registered successes in

preventing possible breakouts in ladles and furnaces in the steel industry (Okah-

Avae, 1996). Electrical and electronics technicians observe signals and work on

control equipment and detect change in temperatures which appears abnormal.

Corrosion Monitoring: Corrosion results from chemical reactions which are

effected by certain variables and conditions such as chemical composition of metal

36

and fluid, temperature, pressure, velocity, stress and physical configurations such

as crevices, beads and elbows (Okah-Avae, 1996). The author explained that some

common types of corrosion experienced in industries include general or uniform

oxidation corrosion, stress corrosion, fretting, pitting, hydrogen embrittlement and

galvanic corrosion.

Physical manifestation of corrosion such as rust staining, bulging, cracking,

or distortion of insulations is easily detected by visual inspection. Equipment used

for visual inspection and maintained by electrical and electronics maintenance

technicians are callipers, pit-gauges, scrapers and brushes, mirror, miniaturized

television cameras and fibre-optics.

Acoustic Emission Monitoring: Most engineering and structural materials emit

sound when their physical state of equilibrium begins to undergo some changes.

Okah-Avae (1996) gave a list of physical changes to include: crack formation,

extension and plasticization in metals; phase transformation in metals, dislocation

movements; disbanding and reinforcement failures in composite materials; friction

mechanisms; and similar destructive phenomenon in any manufactured component

or equipment.

Mechanical failures of equipment are preceded by one or more of these

physical changes and they usually occur at a very early stage of such failures.

Acoustic instrument available which require attention of electrical and electronics

maintenance technicians are instrument, equipment and sensors for measuring,

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transmitting producing, controlling and/or analyzing vibration, sound levels

sinusoidal or oscillatory motion (Global spec, 1999-2007).

Environmental Monitoring: Changes in environmental conditions including

radiation, gases, dust, smoke, moisture and dew analytical meters such as pH

meters, spectrometers and chromatographs are used in manufacturing industries,

and are maintained by electrical and electronics maintenance technicians.

Fisherbrand hydrous series consisting of models 300, 400, 500 and 600 is a variety

of durable, simple microprocessor based pH meter designed to optimize

measurement accuracy (Meserve, 1997). pH meter measures the level of acidity

and alkalinity of gas or substance produced or emitted as by product of production.

Specialized methods – Include Ultrasonic measurements, Shock pulse

measurements, Strain load measurements, Flux monitoring and Industrial

computers.

Electrical and electronics maintenance technicians observe signals maintain

machines, control equipment which detect signals generated and report to

respective maintenance personnel for appropriate action.

Ultrasonic techniques: it is used in flow detection (interval crack and blow holes)

and thickness measurement of metals and other materials.

Shock pulse measurement: it is diagnostic tool for identifying damage at the very

early state. Shock pulse meter (SP) comprises accelerometer with a peak detector

coupled to it. Little shock pulses generated by the bearings are transmitted to

38

excite oscillation at the resonance frequency of the accelerometer. The peak

detector then records the count which gives a measurement of the shock energy.

Strain load measurement: This is used in measuring the integrity of steel and

concrete structures. Strain gauges connected to a meter measure on time strains

along the load line in tension, compression or torsion. Okah-Avae (1996) stresses

that load monitor based on full bridge strain gauges is used to measure roll

separating forces in a steel rolling mill.

Motor flux leakage detection: Failures in motor can either be mechanical such as

bearing degradation, rotor distortion or electrical such as phase failures, inter turn

shorts. Both types of faults aid flux leakages. A search monitored by meter is

attached to the motor to detect increased flux leakage which indicates that the

motor is developing fault.

Industrial Computers: These are intended for use in factory floors or in other

harsh environments. These systems are designed to withstand shock vibration,

humidity, dust, mist and splash. These industrial computers are used for data

processing which helps in records up-date references by monitors and other staff

members.

Errors associated with monitoring tasks:

McCormick and Tiffin (1979) compiled errors associated with monitoring

tasks includes:

(a) failure to detect relevant stimuli or signals

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(b) false detection of stimuli or signals and

(c) response lag.

Monitoring provides true position of conditions of operating equipment

which always require immediate attention of maintenance crew. The electrical and

electronics maintenance technicians in carrying out the maintenance activities rely

upon the information provided by control equipment, their natural senses of touch,

smell, sight and hearing and measuring instruments as means of carrying out (1)

inspection (2) calibration and (3) services and (4) repairs of production equipment

carried out under three levels of maintenance work.

2. Inspection

Inspection processes are somewhat akin to monitoring (McCormick & Tiffin

1979). Inspection is any check-up conducted on an equipment to bring up the

defects which demand immediate and appropriate action. Inspection may mean

testing or checking the conditions of equipment against the established standards.

Three basic elements are utilized when inspecting functional equipment. Harris

and Chaney in McCormick and Tiffin (1979) listed the basic elements to include:

• Interpretation (interpretation of some types of established standard

which defines what is acceptable and what is not).

• Comparison (comparison of the quality of characteristics of the item

being inspected with the specified standard).

• Decision making: (deciding whether the quality characteristics of the

item conforms to the standard or not). The three basic elements are

40

accompanied by action of (disposing of the item, recording the results of

the inspection and so forth).

The basic elements which are accomplished through the inspection tasks are

categorized into three types. McCormick and Tiffin (1979) mentioned them as

follows:

Scanning tasks: Searching for defects by scanning-usually visually but sometimes

by other sense such as by touch;

Measurement tasks: Use of some measuring devices such as micrometers,

multitesters and callipers and

Monitoring tasks: Monitoring some ongoing automatic or semiautomatic process

for indications of out-of tolerance conditions; sometimes this is done by

monitoring instruments.

To carry out the inspection tasks, require some techniques to facilitate the

action of inspection. Harris and Chaney in McCormick and Tiffin (1979)

developed some techniques, which might be relevant in specific circumstances.

These techniques are among the techniques used by electrical and electronics

technicians. They are as follows:

Scanning Methods: (Stationery and moving items) generally people make more

accurate visual discrimination when the object of visual regard is stationary than

when it is moving. McCormick and Tiffin (1979) expressed that results of studies

confirmed the ability of people to make visual discriminations is more for

stationary objects than the moving objects.

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The number of characteristics being inspected at a time is of significant

importance. The explanation for this probably lies in the fact that when scanning

for many types of defects, the inspector is in effect, required to apply several or

many standard simultaneously (McCormick &Tiffin, (1979). The inspection of one

type of defect at a time requires as Chaney and Harris in McCormick and Tiffin

(1979) put it less mental gear shifting. Scanning many types of defects at a time

may overload attention and this sometimes create problem (parliamentary office of

science and technology, 2001).

Overlays in inspection: A photographic overlay which consists of replicated

oversize picture of an item in transparent materials is used. The overlay reflects all

details of the actual item thereby facilitating the making of visual discrimination.

The overlay tools are used in repairs of defective electronics circuits.

Magnification: Magnification offers possible relief for the bleary eyes of the

inspector by increasing the visual size of relevant features so that they are more

within the range of the visual resolution capabilities of the eye. The instruments

used are magnifying glasses.

Visual aids in Inspection: Certain types of items such as visual aids can be used

to enhance the inspection process. They detect such defects as misallocated holes,

improper dimensions, lack of parallelism and concentricity. These aids consist of a

series of simple drawings of the sample parts. The dimensions and tolerances for

42

each characteristic to be inspected are placed on the drawings to minimize the need

for calculation or reference to other materials.

Inspection decision aids: The characteristic of some items being inspected vary

along a quality continuum with some point along the scale being declared to

represent an “acceptable” level. The inspector after the instructional period

therefore is expected to store that image in his memory. In the inspection process,

the inspector makes a judgment about the degree of that characteristic, and in turn

decides if that degree represents a value above or below the acceptable dividing

line. The decision for each characteristics being examined requires in effects, an

absolute decision regarding the degree of the characteristics in question. A number

of psychological investigation have demonstrated that people generally can make

more accurate judgments about the amount or degrees of qualities, traits or

characteristics of object when comparing such objects with each other on relative

basis than when required to make an absolute judgment about the quality

(McCormick & Tiffin, 1979). Inspection decisions could be made more adequately

if the inspector is provided with some representation of the minimum acceptable

degree of the characteristics in question.

Limit Samples: A limit sample is a sample of product that is just barely

acceptable in terms of inspection standards; it represents the limit of acceptability.

When the use of actual limit samples is not feasible, it may be possible to represent

such samples photographically.

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Mather (2004) gave an example of what poor inspection could cause. Fixing

a motor to a new plinth and then aligning it to whatever it is driving is a pretty

standard task. After a few month, new plinth have tendency to ‘settle’ often

forcing misalignment through shifting of the motor. Failure to take this into

account and to perform the necessary ‘checks’ to correct it if it occurs is also a

human error related issue.

Errors associated with inspection:

Inspection activities have some errors associated with them. McCormick and

Tiffin (1979) pointed out the following errors that are often committed during

inspection.

a Forgetting to apply the acceptable criteria for acceptable level of an item in

use, after the instructional period or training: Dunn (2007) described this

situation as output failure; that is things we know but cannot be recalled at

the required time.

b Failure to detect relevant stimuli or signals.

c False detection of stimuli or signals

d Accepting and unacceptable conditions and rejecting acceptable conditions

(McCormick & Tiffin 1979)

Since inspection processes are somewhat akin to monitoring (McCormick &

Tiffin 1979) therefore errors in numbers b and c which occur in monitoring may

likely occur in inspection processes. Inspection in this context is to assess the

conditions of equipment in operation and compare them with the established

44

standards for actions to be taken to keep it in its original working condition. The

appropriate actions may include calibrations, services and repairs.

3. Calibration.

Calibrations are adjustments made on equipment to bring back some drifted

values of electrical parameters such as current or voltage to their pre-set values for

effective operation of the equipment. Calibration is a comparison between

measurements – one of known magnitude or correctness made or set with one

device and another measurement made in as similar a way as possible with a

second device (Wikipedia, 2007). The device with the known or assigned

correctness is called the standard. The second device is the unit under test, test

instrument, or any of several other names for the device being calibrated.

According to Wikipedia (2007), calibration can be called for:

with a new instrument,

when a specified time period is elapsed,

when a specified usage (operating hours) has elapsed,

when an instrument has had a shock or vibration which potentially may have put it

out of calibration, sudden changes in weather and whenever observations appear

questionable

There are manual calibrations and auto calibrations. In manual calibrations,

pre-set variable resistors or capacitors and potentiometers are varied and current or

voltage values are read, compared and set in accordance with the assigned values

as specified by manufacturer of the equipment. Calibration is often regarded as

45

including the process of adjusting the output or indication on a measurement

instrument to agree with value of the applied standard, within a specified accuracy.

For example, a thermometer could be calibrated so the error of indication or the

correction is determined, and adjusted (e.g. via calibration constants) so that it

shows the true temperature in Celsius at specific points on the scale (Wikipedia,

2007).

An example of auto calibration as described is the fisherbrand hydrous series

300, 400, 500 and 600 produced for pH measurements. The pH meters have a

press button incorporated to initiates a change in current set-up parameters

whenever it is pressed (Meserve, 1997).

Visual and static tests are carried out in manual calibrations. The eyes

conduct visual checks and take readings of static tests.

Errors associated with manual calibration

a Miscalibration in planned maintenance and planned operation (Kim & Park,

2008)

Monitoring, inspection and calibrations are all aspects of services of

equipment. Monitoring and inspection precede calibrations, cleaning, oiling and

greasing involved in maintenance services.

4. Maintenance Services

No matter how well equipment has been designed, manufactured,

installed and commissioned, the possibility for failure cannot be ignored. To

prevent failure, maintenance services are carried out. Servicing is carried out by

46

personnel for the purpose of maintaining equipment and facilities in satisfactory

operating condition by providing for systematic inspection, detection, and

correction of incipient failures either before they occur or before they develop into

major defects. Maintenance servicing are those activities which encompass regular

monitoring inspection, clean up, lubrication, adjustment, alignment, calibration,

replacement, or replenishment to prolong an asset’s useful life, prevent its

breakdown and keep it capable of performing its intended function within its

design specifications (Online Business Dictionary, 2009).

Basically maintenance is a service function (Dunlop, 1990). Services are

tasks that are performed for someone else, such as laundry, cleaning, hospital care,

restaurant meal preparations, car polishing, psychological counselling and teaching

(Miller, 1999). Teriba (2004) explained that services, by comparison are products

which have no material existence and can neither be seen nor touched physically

although their results or instruments performing them may be capable of being

seen; for example haircut, insurance, transportation and medical care. Services are

mental or physical labour or help paid for by consumers. Examples are the

assistance of doctors, lawyers, dentists, repair personnel, house cleaners,

educators, retailers and wholesalers; things paid for or used by consumers that do

not have physical characteristics (Miller, 1999). Maintenance service therefore, is

any mental or physical activity or help provided to equipment or asserts to sustain

their working conditions, or to keep equipment as reliable as possible.

The main goal of maintenance services is to prevent machine and equipment

failure and thereby prolong the life of equipment and machines. To achieve this

47

goal, maintenance services are carried out under the umbrella of a number of

maintenance practices or strategies designed to facilitate and enhance its

effectiveness. The maintenance policies or strategies include: Preventive

maintenance, Planned maintenance, Predictive maintenance, Routine maintenance

and Overhaul maintenance.

Atsumbe (1997) explained that preventive maintenance is scheduled

inspection and service procedure which are designed to prevent equipment

breakdown and malfunction through early detection and remedy of causes.

Onadeko (1994) observed that planned maintenance requires the work for service

be planned by scheduling in advance for example for every week. Okonkwo

(1997) explained that routine maintenance falls under preventive maintenance; this

is because of its effectiveness in preventing faults in a system. Okonkwo (1997)

stressed that it is possible with predictive maintenance to identify conditions that

require correction before a major problem develops; so that the need for

disassembly and inspection of internal parts of equipment can be minimized.

Okonkwo (1997) observed that overhaul maintenance should follow planned

maintenance procedure in an industrial setting in order to prevent losses due to

downtime. All the maintenance practices have similarities because their

applications and concepts overlap.

There are two types of maintenance services currently in use in

manufacturing industries. They are (a) minor and (b) major maintenance services.

a, Minor Maintenance Services include

• Changing of oil (transformer)

48

• Lubricating the specified part

• An inspection of all fluid, belts, loses etc

• Some manufacturers recommend calibrations or adjustment of voltages

b, Major maintenance services include

• All minor services

• Replacement of parts at the manufacturers recommended replacement

intervals

• Other specified major services related to the pneumatic and fluid control

systems

In manufacturing industries major maintenance services are carried out in

form of overhaul maintenance. Overhaul maintenance involves a complete

disassembly of machinery and equipment, location of faults, replacement of major

and other parts which depreciated in function, total repair of parts and then

reassembly. This practice ensures that machines and equipment are brought back

to their optimum function to maintain maximum efficiency.

Maintenance services required for serviceable equipment are based on

• Manufacturers’ recommended or service manuals and specifications,

• Knowledge of particular equipment

• Years of experiences on the job

• Work procedure

Other requirements which may also serve for maintenance services as well as

repairs are listed by Atsumbe (1997). They include:

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• Facility registers

• Maintenance schedule

• Job specification

• History records

• Service Manuals:

Most manufacturers of equipment publish and make available to customers

complete repair and calibrations or tune up data in form of shop manuals or service

manuals. The manufacturer’s manuals spell out among others procedures for

carrying out maintenance services. These maintenance services vary with different

equipment.

Specifications of equipment parts or equipment are also provided in the

manufacturers manuals. These contain part names and numbers. The specifications

are provided to facilitate replacement of individual parts nearing the end of their

life span before they actually fail. Specification also helps to determine the correct

item during procurement.

Maintenance services activities are effectively carried out based on relevant

work experiences on particular equipment and knowledge of construction and

operational principles of the equipment. Against this background job vacancies

require relevant qualifications and years of relevant work experiences (Sinclair,

1988).

Facility records establish what have to be maintained. The register contains

information like either the unit is mechanical or electrical, constructional and

technical details, drawings, and manufacturers’ handbooks. It may be useful to

50

include other information such as available spare parts. External maintenance

services and major components part may require separate cards, for example,

power units’ gearbox.

Maintenance schedule indicates how maintenance is to be carried out.

Maintenance schedule presents a comprehensive picture of the work to be done to

each item and at what intervals must be done. Job specification is prepared from

the maintenance schedules, detailing various periods which maintenance is

required by individual machines. The extent of details depends on the equipment

to be maintained.

History record: The history card is for the recording and analysis of results

achieved. Each plant item should have a history card. This summarizes details of

adjustments made, failures, actions taken to rectify them, causes of breakdown and

manpower used. The history card helps in future when similar faults occur.

Maintenance services have some advantages over maintenance repairs:

• Maintenance service reduces the rate of breakdown

• It reduces the cost of maintenance

• It provides for formation of ideas about the competencies of technicians.

• It provides ground for modification or replacement of equipment before

the havoc is done

• It is the basis for stable maintainability hence stable production

• It equips technicians with knowledge and skills for repairs.

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Maintenance services may be carried out on serviceable equipment. This

serviceable equipment may contain units that may be unserviceable. Such units if

are found problematic are simply replaced after careful inspection and testing.

Maintenance services are carried out to ameliorate the likely deteriorating

operating conditions of equipment that may cause equipment breakdown. Its

activities however, integrate maintenance repairs in the event of likelihood of

occurrence of fault envisaged through inspection activities during maintenance

services.

Errors associated with maintenance services

a Forgetting to apply acceptable criteria (Dunn, 2007)

b Failure to perform necessary checks (Mather, 2004)

c Omission (Riggio, 2000)

d Forgetting intention to do something (Dunn, 2007)

e Accepting an unacceptable condition and rejecting an acceptable condition

(McCormick &Tiffin, 1979)

f Terminating job before all actions are complete (Dunn, 2007).

5. Maintenance Repairs:

Maintenance repairs are carried out due to deteriorating condition of or

faults in the equipment. Maintenance repair is intended to restore malfunctioning

or failed or broken-down equipment to its original working condition.

Maintenance repairs are the actions involved in fixing to its original working

condition any sort of mechanical or electrical device should it become out of order

52

or broken (Defense Logistica Agency of mechanical or electrical, 2011).

Maintenance repairs can be defined as restoration of a broken, damaged, or failed

device, equipment, part, or property to an acceptable operating or usable condition

or state (London School of Business and Finance, 2009). Repair or corrective

maintenance can be defined as a maintenance task performed to identify, isolate,

and rectify a fault so that the failed equipment, machine, or system can be restored

to an operational condition within the tolerances or limits established for in-service

operations (Wikipedia, 2011). Repair is carried out after failure detection and is

aimed at restoring an asset to a condition in which it can perform its intended

function. Repair or corrective maintenance can be subdivided into "immediate

corrective maintenance" (in which work starts immediately after a failure) and

"deferred corrective maintenance" (in which work is delayed in conformance to a

given set of maintenance rules).

Maintenance repair is reactive. It is done at machine level, one machine at a

time. It is a fail-and-fix approach. Troubleshooting is the primary purpose.

Troubleshooting refers to diagnostic or corrective maintenance, which is

performed to correct an already-exiting problem. Maintenance repair deals with

breakdown or other problems such as wobbling and worn out units when they

occur. Stephenson (1999) referred to it as breakdown maintenance. Maintenance

repair is carried out under following maintenance practices. They include:

Breakdown maintenance or corrective maintenance, Fixed time maintenance,

Operate-to-failure, Planned maintenance and Opportunity maintenance.

Maintenance repairs depending on the situation may introduce minor changes in

53

design, and substitution of more suitable components or improved materials of

construction to eliminate problem, Okonkwo (1997) added.

Fixed time maintenance is the repair or replacement of parts at periodic

intervals prior to failure (Okonkwo, 1997). Atsumbe (1997) explained that fixed

time maintenance is dependent on time. A component failure and components

wear are clearly time dependent.

Operate-to-failure is an application of corrective maintenance, after failure,

the measure is to return the instruments or equipment to an acceptable condition in

the most economical manner (Onadeko, 1994). It involves repairs in the suppliers’

or organizations’ workshops or replacement of bad item which is very expensive.

Planned maintenance involves a whole range of maintenance work and it

applies to any type of maintenance policy such as corrective, breakdown and

preventive maintenance (Onadeko, 1994). Okonkwo (1997) expressed that the

overall plan includes, as a rule, inspections and replacements of parts that are

worn, and adjustments. Corrective maintenance is concerned with the detection,

location, and repair of faults as they occur. It is referred to variously by service-

men as breakdown maintenance, repair maintenance or replace-as-they fail

(Okonkwo, 1997).

Opportunity maintenance is used to describe maintenance actions carried out

during planned maintenance or after failure or during fixed-time or condition-

based repair, but specifically concerned with items other than those that originally

cause of the maintenance work or repairs (Atsumbe, 1997). Opportunity

maintenance work may arise as a result of chance observation or may form part of

54

an operate-to-failure policy. Corrective maintenance is mainly concerned with

equipment failures. The equipment failures however occur randomly such that

corrective maintenance cannot be really programmed in advance. Instead

corrective maintenance guidelines are formulated. The corrective maintenance

guidelines cover fault finding techniques and other repair processes required to

restore the equipment to the original conditions.

It is recognized that all electrical and electronics equipment of a given type,

work on a particular principles and can therefore suffer the same defects, hence

they are amendable to the same techniques. Onadeko (1994) explained that

specific defects will cause the same complaints in all types of equipment. A faulty

integrated circuit (IC) in an amplifier can cause a distortion due to a “leakage”

transistor or capacitor. It depends upon the use the amplifier is put to as to the

symptoms shown.

(a) In a test instrument: Inaccurate reading would occur (b) in control circuit:

erratic operation would be observed, (c) in a radio transmitter: harmonic radiation

may be introduced, (d) in an audio amplifier: a distorted sound would be heard,

and (e) in a television video section: a smeared picture would be seen (Onadeko,

1994).

The fact is that the basic fault is the same, the basic circuit is the same and

the basic maintenance technique which can be used for examples signal tracing

with oscilloscope and static test with multi-tester is the same. Fault finding

techniques may be diagnostic techniques. The choice of diagnostic technique or a

combined number of them depends on the situation such as the range of test

55

equipment available, the environment that is whether the faulty device can be

moved to the workshop or be repaired on site. Onadeko (1994) stressed that there

are very basic checks which should always be carried out right at the start of any

fault investigation; this involves use of senses such as eyes, ears, and nose. Eyes

are used for detailed visual checks; ears are employed to detect incorrect operation

particularly of mechanical or moving parts. Noses are used to smell obvious

odours due to damages such as burnt out component or motor windings.

Visual inspection or checks is commonly used in repairs of equipment and

machines in manufacturing industries. A close observation using visual senses to

detect or locate fault in equipment is the first action to repair. Onadeko (1994)

explained that visual inspection includes:

• Checking state of equipment,

• Looking for obvious signs of damage

• Confirming with the operator the description of the symptoms.

• Asking if anything unusual has occurred; was environment normal, was

the unit operated correctly.

• Checking if batteries are involved first.

• Checking for LIVE signs.

Fullerton (1996) expressed that when equipment breaks down, the repair

processes is to: (1) examined work orders, which indicate problems or talk to

equipment operators (2) check for common causes of trouble such as loose

connections or obviously defective components (3) if routine checks do not locate

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the trouble, refer to schematics and manufacturers’ specifications that show

connections and provide instruction on how to locate problems such as

troubleshooting.

The visual checks and routine checks are necessary to help localize the fault.

Diagnostic techniques or programme are run to pinpoint malfunctions. These

involve the use of multi-tester signal generators and oscilloscope, voltage testers,

pair of pliers, screw drivers and sometimes spanners and soldering irons. The

diagnostic techniques are: static test, dynamic test, vibration technique or brute

force, signal tracing method, signal substitution test and sensory test by technicians

as pointed out by Pachett (1972), Onadeko (1996) and Okoro (1992).

Sensory Test: This requires the use of human senses such as sense of smell, sense

of touch, sense of hearing and sense of vision. The eyes are used for visual checks

such as looking for likely signs of damage, burns and cracks or opening or

closures. The ears are used to detect noise from malfunctioning parts particularly

mechanical or moving parts. The nose is used to perceive the odour of burnt parts,

components such as motor windings, capacitors and resistors. Hands are used as

sense of touch to feel heat and vibration of shaft or wobbling moving parts. The

sensory test is followed by static test to isolate the fault.

Static tests: This involves measurement of voltages, resistance and current.

Voltage measurements are used to check the steady or direct component of voltage

in the circuit; resistance measurements are carried out only when the affected

components is isolated or removed off the circuit. The resistance readings are then

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taken with the multi-tester. Current measurements are made by breaking the circuit

and connecting the ammeter in series with the suspected components. The circuit

is then switched on and current value is read from the ammeter. In all current

measurements and in all cases involving static test, the readings are compared with

readings of the service manual, reference instrument, schematic diagrams,

reference books, technical knowledge and work experience.

Dynamic test: This is carried out under full operating conditions of the device.

The test is to locate faults which affect signal voltages but do not affect the steady

voltages across the circuit as measured by the static tests (Patchett, 1972). It can

isolate all types of troubles such as components defects, serious changes in

equipment operation and minor defects. It is useful in tracking down intermittent

faults. There are two types of dynamic tests. They are (a) signal tracing test and (b)

signal substitution test.

(a) Signal tracing test: This is carried out when the equipment is in operating

conditions. An oscilloscope is used to display on screen the signal of each stage of

the circuit. The stage where the signal is lost, the associated components are

suspected and are subjected to voltage test, or removed for resistance test.

(b) Signal Substitution test: When the equipment is in working condition, signals

generated by signal generator or injector is injected into the input circuit to be

detected by the oscilloscope at any point of the circuit. This is to help identify

which stage of the equipment the signal fails to pass due to its malfunctioning

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state. Resistance tests are then carried out to find out the defective component in

the section where the signal is lost.

Brute force technique: This technique is good for locating, intermittent faults.

With this method, fault can be brought on or located by lightly tapping, wriggling,

bending or twisting the equipment for the source of intermittent fault. Components

are changed when it becomes necessary.

The method of testing used to locate the sources of trouble or fault are based

on the operating principles of the mechanism, and the type of system. This makes

it easy for the troubleshooting pointers to be prepared (Althouse, Turnquist &

Braccino, 1974).

When the fault has been identified repair task are performed to restore the

equipment into original working conditions. The repairs involved are to amend or

replace or recondition the component affected. The confirmation of the working

condition is made by test running the equipment.

Equipment repairs have been made relatively easy. More equipment now has

self diagnosing features which greatly simplifies the work (Fullerton, 1996). In

addition, equipment is now designed in modular form of complete unit or sub-unit.

The unit or sub-unit can be replaced easily whenever it fails. This saves time and

cost of repairs.

Repairs of plant or equipment in industry or factory can be contracted into

expert’s hands. This is to ensure good workmanship and reliability of equipment.

Repair work in manufacturing industries are carried out either in the; (1) workshop

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or (2) industrial site-equipment location depending on the condition of the

equipment. Defective components and machines requiring extensive repairs are

sent to the workshop. Fullerton (1996) observed that shop repairers determine the

source of a problem in the equipment and may estimate whether it is wiser to buy a

new part or machine or to fix the broken one.

The repair process is systematic. It involves series of steps or procedures to

be followed, leading to replacement of damaged or malfunctioning or worn out

component of equipment and adjustment of belts, chains or retightening of the

slackened screws or belts. When effecting repairs or carrying out checks, the

reading may be compared with:

• Service manuals,

• Reference instrument,

• Schematic diagnosis,

• Reference books,

• Our technical knowledge (Onadeko, 1994) and

• Working diagrams for mechanical units.

• If in doubt, it may be best to seek for advice, or relevant information

from experts before anything is changed; confirm the correctness of the

diagnosis

Equipment conditions may require both maintenance repairs and

maintenance services. The equipment conditions which require both maintenance

services and repairs may be specified by maintenance policies such as opportunity

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and overhaul maintenance. Onadeko (1994) explained that opportunity

maintenance describes maintenance actions carried out during planned

maintenance or after failure, or during fix time but specifically concerned with

items other than those originally cause the maintenance work or repairs. Okonkwo

(1997) expressed that overhaul maintenance ensures that machines and equipment

are brought back to their normal optimum function to maintain maximum

efficiency. Onadeko’s and Okonkwo’s explanations of the two maintenance

practices seem to relate maintenance services and maintenance repairs together.

Maintenance service activities are designed to detect potential failures

conditions and make minor adjustments or repairs which will help prevent major

operating problems (Monk, 1982). Based on this assertion maintenance services

may not be completely isolated from maintenance repairs.

Both maintenance service and maintenance repair activities are interwoven.

There is no clear cut demarcation between the two practices. However, there

stands out one distinct property that seems to separate the two, that is the need.

Maintenance repairs are carried out when there is a breakdown, damage, fault or

problem with the equipment. In absence of faulty conditions maintenance repairs

turn out to be maintenance services.

Errors associated with maintenance repairs:

a, Errors of omission: This is failure to do something. An example would be an

electronics failure to shut off the power before working on electrical

61

circuitry; (Riggio, 2000). Omission of steps in maintenance tasks is cited as a

substantial cause of nuclear power plant incidents (Rasmussen, 1980).

b, Errors of commission: This is performing an act incorrectly (Riggio, 2000).

Violating safety rules or breaching procedures of the task being performed

(Mather, 2004-2007 and Dunn, 2007).

c, Error of judgment: Sometimes technicians may be faced with a trade- off

decision of replacement or continued maintenance of a particular equipment.

A decision taken may be in error. Such decision such as accepting newer

equipment which may have features that favour replacement over either

preventive or breakdown maintenance. On the other hand, accepting the

removal of old equipment and the installation of new equipment which may

cause disruptions to the system, perhaps greater than the disruptions caused

by breakdowns” (Stephenson, 1999).

Operational Levels of Maintenance Work: From the illustration on the

maintenance activities, it is clear that monitoring and inspection facilitate

calibration, services and repairs of equipment operated under three operational

levels of maintenance work. Dunlop (1990) listed the three operational levels of

maintenance work as follows:

• First level: Station keeping (operations) routine on site work such as

periodic lubrications, cleaning, checking and small adjustment.

• Second Level: Field or running maintenance crew is seconded to the

equipment for preventive maintenance or corrective maintenance.

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• Third Level: Planned and preventive maintenance, planned non-

availability, overhaul, repair, fabrication and assembly.

In Nigeria’s manufacturing industries, the three levels of operations fall

under the following maintenance practices or options: Preventive maintenance,

planned maintenance and emergency maintenance. Planned maintenance involves

planning for maintenance work such as major repairs, services or overhaul.

Emergency maintenance involves the repair, ratification as soon as possible

depending on the failure. Preventive maintenance deals with servicing equipment

or plant to prevent equipment breakdowns or failures. The goal of preventive

maintenance is to reduce the incidence of breakdown or failures in the plant so as

to avoid the associated cost. Those costs can include loss of output, idle workers,

repairs, injuries, and damage to other equipment, product or facilities (Stephenson,

1999). Murphy and Martin (1977) expressed that the major idea behind preventive

maintenance is that it is better to do little now rather than a lot later. Corrective

maintenance deals with breakdowns or other problems when they occur

(Stephenson, 1999). Corrective maintenance is referred to variously by serviceman

as breakdown maintenance or replacement-as-they-fail (Okonkwo, 1997).

Corrective maintenance is usually emergency is nature, where facilities or pieces

of equipment are used until they fail to operate; then they are repaired often at cost

premium (Monk, 1982).

There are other maintenance strategies or options which stem up from

preventive and corrective maintenance options. Some of these maintenance options

are duplication of other maintenance options under different names. Other

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maintenance options owe their names from their functions. Onadeko (1994) listed

the maintenance options to include:

Condition base maintenance: This is a continuous or regular measurement and

recording of data to indicate the deterioration of an instrument in order to provide

warning against breakdown in the interest of safety and economic operations.

Fixed maintenance: This is the repair or replacement of parts at periodic intervals

prior to failure.

Design out maintenance: This aims at eliminating the actual cause of failure and

maintenance work.

Operate-to-failure maintenance: This is an application of corrective maintenance

after failure; the measure is to return the instrument/equipment to an acceptable

condition in the most economical manner. This type of policy is very expensive,

because when failure occurs there are two alternatives (i) to repair in the supplier’s

workshop or in the organization’s workshop; (ii) replacement of bad items

completely, which is a measure that is more expensive.

Opportunity maintenance: This describes maintenance actions carried out during

planned maintenance or after failure or during fixed-time, but specifically

concerned with items other than those that originally cause the maintenance work

or repairs.

Planned maintenance: This describes the manner which maintenance work is

carried out with fore-thought control and records, and involves the comprehensive

planning of the maintenance foundation. The policy involves a lot of benefits such

as lower cost of maintenance, improved safety, improved quality and creates high

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morale of working with the instrument. Planned maintenance involves a whole

range of maintenance work. It applies to any type like, corrective, breakdown and

preventive maintenance.

Okonkwo (1997) added to the list of maintenance options, the following:

Predictive maintenance: This is to identify the conditions, which require correction

before the major problem develops.

Overhaul maintenance: This involves a complete disassembly, location of faults,

replacement of major parts then assembly.

Eliminative maintenance: This is used to designate an approach that strives to

minimize the necessity for maintenance. The list of maintenance options is

extended by Atsumbe (1997) to include routine maintenance: Routine maintenance

is cyclic in nature. It defines the amount of time, number of units in a given time

and the type of work to be performed at specific times by specific number of

personnel.

Whatever name is given and whichever function is performed maintenance

options is a description of maintenance work in a specified time. Maintenance

work is planned before work commences by someone. The work for every

maintenance man is scheduled and conditions are such that these schedules are met

at high percentage of time (Dunlop, 1990). When a manufacturing industry is

running or equipment are on load, the electrical and electronics maintenance

technicians are seconded to equipment or placed on specified location or “station

keeping” for specified time for preventive maintenance such as monitoring, routine

checks or inspection of operating condition of machines and equipment (Dunlop,

65

1990). Where necessary the electrical and electronics maintenance technicians

disable a unit to ratify a particular defect if it affects the safety of personnel or

plant or can lead to inevitable loss of production. In some cases, defective

instruments and equipment which require removal but not causing damage to the

plant may be left until sufficient number have occurred and the respective section

of the plant is put off or shut down at suitable production time (Dunlop, 1990).

They are then replaced eventually.

Electrical and electronics maintenance technicians may be assigned to the

workshop to work on work elements brought from site and complete work on them

as designated. They determine the source of the problem in the equipment, and

may estimate whether it is wiser to purchase a new part or machine or fix the

broken one” (Fullerton, 1996).

After the manufacturing industry has run for a period of time, it may be shut

down for specified period for overhaul maintenance. Overhaul maintenance

involves major repairs and services. Overhaul maintenance because its actions are

scheduled is a preventive maintenance. Overhaul maintenance is unlike corrective

maintenance which its actions because of random failures cannot really be

programmed in advance. Corrective maintenance guidelines are formulated when

failure occurs. These corrective maintenance guidelines normally result in what

could be called fault-finding techniques in order to restore the machine or

instrument to its original conditions.

In applying fault-finding techniques, the electrical and electronics

maintenance technicians demonstrate mastery of work experience, considerable

66

mental skill in diagnosing faults and wealth of practical skills in making necessary

repairs without damage to components. Acts which may cause damage to

equipment such as breaking or otherwise disobeying specific safety and plant

regulations or gross misuse of machinery or careless handling of tools or

equipment are serious misconduct (Ashaka Cement Company Limited, 1978).

Such serious misconduct may lead to errors in maintenance.

In order that effective maintenance of machines and equipment be performed

with minimum errors: (1) Manufacturing industrial organizations employ skilled

technicians on the basis of relevant work experience and place them on probation

before their appointments are confirmed. (2) Some manufacturing industries such

as Ashaka Cement and Benue Cement Companies and Ajaokuta steel company

have training centres to train the technicians to provide the best maintenance of

their respective machines and equipment. Electrical and electronics maintenance

technicians may undergo retraining to up-date their mental and practical skills

required for effective services and repairs of equipment and machines within their

work schedules.

Work schedules for electrical and electronics maintenance technicians are:

Normal working time (42 hours per week), Shift, Call duties and Overtime

Normal working time: The number of hours referred to as normal working time

is forty-two hours (Riggio, 2000; Robbins, 2000 and Landy & Conte, 2004).

Robbins (2000) explained that most people work an eight-hour day, five days a

week. They start at fixed time and leave at fixed time. In Nigeria’s manufacturing

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industries, the time spans from 08.00AM to 05.00PM with one-hour break time

inclusive.

Shift work: Shift work is defined as any arrangement of daily working hours that

differs from the standard daytime hours, that is between about 07:00 and 19:00

(Folkard, 2007). Shifts may also vary in terms of day worked. An employee may

work for five days and go on a two-day off, although a number of variations are

available (Riggio, 2000). Landy and Conte (2004) observed that the scheduling of

work according to a particular time period is called shift work. Numerous research

studies on shift work centred on the twenty four hour or circadian cycle of human

whose physiology tends to make them active during hours of light and inactive

such as sleeping and resting during hours of darkness (Riggio, 2000). According to

Landy and Conte (2004) workers assigned to shift during day light hours are

following the circadian cycle while those whose shift includes hours of darkness

are working against the cycle. The author maintained that psychologists have

found that in general, the disturbance of the circadian cycle has adverse effects for

health, performance and general satisfaction. Landy and Conte (2004) classified

shift into two types; namely: fixed shift and rotating shift.

Fixed Shift: Typical shifts consist of a morning or a day shift from 06.00 AM to

02.00 PM; an afternoon (swing) shift from 02.00 PM to 10.00 PM; and a night or

‘grave-yard’ shift from 10.00 PM to 06.00 AM (Riggio, 2000). Monk, Folkard and

Wedderbum (1996) observed from researchers that night shifts may disrupt the

natural sleep and waking cycles of workers’ bodies often referred to as “circadian

68

rhythms” and may led to problems such as high rate of stress, fatigue, job

dissatisfaction and performance errors.

Rotating Shift Schedule: Shift can rotate rapidly (that move to a different every

week) or slowly (for example a worker can change shifts every three months).

Rotating shifts lead to sleep disturbances, which in turn are associated with

medical (that is gastrointestinal) and psychological problems (for example anxiety

and depression) (Landy & Conte 2004). Investigations have shown that inadequate

information exchange during shift and turnovers can have serious consequences

such as personal injury and equipment damage (Root Cause Analysis Tool Kit,

2007)

Call Duties: Technicians may be placed on call. While on call he may be called at

any time to handle equipment failure (Fullerton, 1996). A technician on call duty

rests at a place of convenience for example, his house which is accessible to his

callers.

Overtime: Because factories and other facilities cannot afford breakdowns of

industrial machinery, repairers may be called to the plant at night or on weekends

for emergency repairs. Overtime is common among industrial machinery

installation, repair, and maintenance workers—more than a third work over 40

hours a week. During power outages, industrial machinery installation, repair, and

maintenance workers may be assigned overtime and be required to work in shifts

to deal with the emergency.

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Overtime is a trade-off between leisure and normal working hours. The

overtime provision of the fair labour standard Act (FLSA) establishes who is to be

paid and who is not (Ugwudioha, 2004). Most employees covered by the FLSA

must be paid time and a half for all work exceeding forty hours per week. Ashaka

Cement Company Limited (1978) stated that the payment for authorized overtime

to staff in grades eligible for such payments are made at the following rates:

• Weekdays - Time and one quarters

• Saturday - Time and one half

• Public Holidays - Double time

Overtime if not controlled may become an unnecessary burden. This may

affect the performance for error to occur.

Maintenance work carried out by electrical and electronics maintenance

technician involves lifting, reaching, stooping, crouching and crawling. Some

work may expose technicians to heat, grease, and noise on the factory floor. Some

may have to work under cramped spaces (Fullerton, 1996). In every situation,

adherence to safety precautions is essential to guard against work hazards such as

minor burns and electric shock, yet there are some incidents, due to human errors.

Dhillon (2006) revealed some maintenance error-related facts and figures are as

follows:

• A study of maintenance errors occurring in missile operations reported

many causes for their occurrence: wrong installation (28%), dials and

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controls (missed or misread) (38%), inaccessibility (3%), loose nuts or

fittings (14%), and miscellaneous (17%).

• A study of maintenance tasks such as aligning, removing, and adjusting

reported an average human reliability of 0.9871. This means one should

expect around 13 errors in every 1,000 such maintenance tasks.

• In 1983, a passenger aircraft departing Miami, Florida, lost oil pressure

in all three of its engines as a result of chip detector O-rings that were

missing, because of poor inspection and supply procedures followed by

maintenance personnel.

Maintenance Jobs are defined by the collection of tasks that an individual is

expected to perform. However, a number of factors contribute to human error

during performance of maintenance work. The contributing factors are causes of

maintenance errors

Causes of Maintenance Errors

Naturally, when errors occurred, they were usually blamed on individuals,

not systems. Hollnagel (1993) in Fogarty, Saunders and Collyer (1999) put

forward a number of reasons for the emphasis on human fallibility of which at

least two have implications, for example, for the aviation industry. Firstly, the

reliability of mechanical and electronic components has increased markedly in the

past 50 years while the level of human reliability has remained virtually unaltered

over the same period. Secondly, the increase in system complexity and automation

has placed greater demands on those responsible for their maintenance.

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Mason (2009) noted that human performance can be affected by many

factors such as age, circadian rhythms, state of mind, physical health, attitude,

emotions, propensity for certain common mistakes, errors and cognitive biases

among others. Reason and Hobbs (2003) identified a number of physiological and

psychological factors such as differences between the capabilities of long-term

memory and our conscious workspace, vigilance decrement, impact of fatigue,

level of arousal, and biases in thinking and decision making to contribute to

inevitability of human error in maintenance. Broadly speaking, causes of

maintenance errors cannot be explained without a focus on human characteristics

and working environment of manufacturing industries.

Human Characteristics

Human characteristics can lead to difficulties in interacting with the working

environment. Therefore human factors in workplace safety settings, peoples’

capabilities and limitations must be understood.

Thirst and hunger control the body system and behaviour and they affect the

capabilities and limit performance of individuals. Most people describe thirst as

dryness in the mouth and throat (Hilgard, Atkinson & Atkinson, 1979). Thirst

lowers the level of concentration or reduces attentiveness, thus creating chances

for error to occur. A hungry man is preoccupied with objects associated with food.

Blair, Jones and Simpson (1979) explained that a person who is hungry

experiences first some general increase in activation and directs his energies and

attention towards objects likely to satisfy the hunger drive. The physiological

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conditions of hunger and thirst may affect human characteristics such as

perception, attention, memory and logical reasoning.

Perception: Perception is the process by which we organize and interpret pattern

of stimuli in our environment (Hilgard et al, 1979). Ruch (1984) observed that

perception involves interpretation of sensory information. Hospers (1976)

explained that perception is impossible without sensing or without something

given to the sense, but it involves more. According to the author when one opens

his eyes he has certain visual experiences sense-data; in this he is passive and

cannot help what he sees. But in addition to this passive intake of sense data there

occurs an activity that can be called interpretation: no sooner are sense data present

to sense that the process of interpretation sets in either consciously or

unconsciously. Perception is determined by perceptual abilities. Landy and Conte

(2004) listed them to include:

Speed of closure: This is the ability to quickly make sense of information that

seems to be without meaning or organization. It involves quickly combining and

organizing different pieces of information into a meaningful pattern.

Flexibility of closure: This is the ability to identify or detect a known pattern (a

figure, object, word or sound) that is hidden in other distracting material.

Perception speed: This is the ability to quickly and accurately compare letters,

numbers, object, pictures or patterns. The things to be compared may be presented

at the same time or one after other. This ability also includes comparing a

presented object with a remembered object. Failing to or deficiency to combine

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and organize different pieces of information into a meaningful pattern, to identify

or detect a known pattern that is hidden in other distracting material and to quickly

and accurately make comparisons of letters, numbers, objects, pictures or patterns

can be interpreted to mean the basis for recognition failures type of maintenance

errors.

Perception is influenced by the following factors. They are the perceiver, the

target and the situation. The individual’s interpretation of what he sees is heavily

influenced by his personal characteristics. Among the more relevant personal

characteristics affecting perception are attitude, motives, interest, past experiences

and expectations.

Attitude is a like and dislike, a positive or a negative evaluation about some

aspect of the world (Hilgard, Atkinson & Atkinon, 1979). Attitude is a description

of a proclivity of an individual to respond in a certain way toward something.

Attitude helps to determine not only what is seen but how it is seen. Attitudes are

acquired through experiences that have a pronounced affective component (Blair et

al, 1979). There are positive and negative attitudes. Negative attitude signifies that

interests and energies are aimed at something else. Negative attitude thus can be

endangering loophole in maintenance as it cannot provide required interest for

attention be anchored. As a result error can easily occur.

Interest is desire to understand or to share. Interests are attitudes that cause a

person to seek more activities in a given area. According to Pearson and Nelson

(1985), people are sometimes suspicious, defensive and distrustful as well as just

disinterested. The reason for their suspicions and distrust may be complex, but the

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result is disastrous to effective communications in team work such as in

maintenance.

Motives are drives which find direction towards specific classes of incentives

or reinforcers. According to Blair, Jones and Simpson (1979), motives are highly

individualized. A drive is an aroused state that results from some biological need,

such as a need for food, water, oxygen, or avoidance of painful stimuli. The

authors explained that aroused condition motivates the organism to remedy the

need. The organism seeks to reduce the drive by doing something to satisfy the

need. An unsatisfied need or motive stimulates individual and may exert a strong

influence on perception.

Past experiences narrow one’s focus. According to Robbins (2000), in many

instances one’s past experiences nullify an object of interest. The fact is that

people perceive those things to which they can relate. Things of technical nature

that are learnt in schools and other things elsewhere are all past experiences that

technicians do relate to maintenance jobs. The orientation and training given to

employees also provide opportunity for them (employees) to perceive the extent of

industrial activities. The training given in form of orientation and educational

background are past experiences which relate to maintenance work. Training helps

to reduce error (Dunn, 2007).

Expectation can distort ones perceptions in that one will see what he expects

to see. Expectations are likely to be responsible for violations in maintenance.

Some violations result from well-intended attempt to do something.

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Characteristics of the target that is observed can affect what is perceived.

Motion, sound, size, intensity and other attributes of a target shape the way one

sees it. Parliamentary office of science and technology (2001) stated that the more

intense a stimulus (such as light or a noise), the more powerful the response

elicited (such as brain activity or a physical movement). According to the

Parliamentary Office of Science and Technology (2001), this has implications for

the way danger signals are perceived at work. For instance, the order in which the

severity of danger is signalled on the United Kingdom (UK) rail tracks is single

red indicating most dangerous, followed by single yellow, the double yellow, and

finally green, implying no danger. Error in not differentiating colour of signals

may amount to disaster.

In order to interact safely with the world, one must correctly perceive it and

the danger it holds or one may perceive incorrectly. The parliamentary office of

science and technology (2001) expressed that one of the biggest obstacles one

faces in perceiving the world is that one is forced to interpret information he senses

rather than access it directly. One may see red and mistake it for green. Hospers

(1976) described this phenomenon as perceptual error. One may be lying when he

sees red when he really sees green. He may make a slip of tongue and get wrong

words out. Most importantly he may be making verbal error (Hospers, 1976).

Perceptual error may influence the understanding of language, and subsequent

errors in language. This situation may affect electrical and electronics technicians

during maintenance activities. Griffith and Mahadevan (2006) in their research

study on language error concluded that language error exists, though there are

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recovery mechanisms and mitigating factors. Language error may affect

communication and may lead to error in team work in maintenance.

Parliamentary office of science and technology (2001) observed that work

environments often challenge human perception systems and information can be

misinterpreted. The Parliamentary Office of Science and Technology (2001)

advised that we must perceive correctly to avoid subsequent disaster arising from

our misinterpretation. In maintenance activities technicians are exposed to work

written instructions, manuals, graphics, diagrams and signals to interpret. They

have to interpret information correctly to avoid disaster which may arise from

misinterpretation.

Physical characteristics of documents and graphics affect the legibility of

information and therefore, impact the ability to accurately perceive this

information. Parliamentary office of science and technology (2001) observed that

the more visual information available to the perceiver, the less likely it is that

errors will be made. Available visual information for services and repairs of

equipment to reduce errors listed by Onadeko (1994) include; service manual,

reference instrument, schematic drawing, reference books and measuring

instruments.

Hilgard et al (1979) explained that an individual’s perceptions are selective;

he or she does not react equally to all stimuli impinging upon him or her. Instead

he or she focuses on a few. This perceptual focusing is called “attention”. Through

attentive processes selected stimuli are kept in focus and distracting stimuli” are

resisted.

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Attention: Maintenance Jobs are influenced by information processing

characteristics such as attention allocation. Attention may be seen as steady

application of the mind and effort towards event, item, problem, experiences,

needs, expectancies, expectations and physical properties of stimuli and objects of

importance. Attention is the focusing of perception leading to heightened

awareness of a limited range of stimuli (Hilgard, Atkinson & Atkinson, 1979). Our

internal needs, expectancies, past experiences, motives and expectations are

important physical characteristics of the stimuli which attract attention (Hilgard, et

al, 1979). Other physical properties of stimulus that are important in gaining

attention are intensity, size, contrast and movement. The authors explained that

sometimes momentary interest and emotional states especially moods control

attention.

The modern workplace can overload human attention far in excess of that

encountered in the natural world. This is particularly the case with workspace.

According to Kara and Collin (1992), workspace is a subset of the physical

environment. It contains the task and the equipment, documentation and personnel

required to perform the task. While illumination is an attribute of the physical

environment in general, task lighting (such as a flashlight) is an attribute of the

workspace. The degree of physical access afforded by the workspace is an

important constraint on performance.

Dunn (2007) observed that attention is closely linked with activities of the

conscious workspace, and conscious workspace has extremely limited capacities

including:

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• Attention is an extremely limited commodity. If attention is drawn to

one thing then it is by necessity withdrawn from other competing

concerns (Dunn, 2007). Some activities require more attention capacity

than others, and the total amount of capacity available at any given time

changes. Kahneman in McAdnrew (1993) observed that individuals

must have some ‘attention policy’ to parcel out the available capacity to

competing demands. This may help to reduce error rate.

• The capacity limits give attention its selective properties. Dunn (2007)

explained that an individual can only attend to a very small proportion

of the available sensory data he or she receives. Landy and Conte (2004)

gave operational definition of selective attention as “the ability to

concentrate and not be distracted while performing a task over a period

of time. Hilgard et al (1979) pointed out that expectancies, internal

needs and past experiences are determinants for selection of attention.

Lack of practical skills and knowledge of the job, lack of satisfaction of

physiological needs such as hunger and thirst can limit the capacity

required to determine the selective attention.

• Unrelated matters can also capture attention. These include

preoccupation with other sensory or emotional demands. Emotional

state such as mood and sometimes momentary interest such as picture of

lost friend can control attention and make it possible for errors to be

committed.

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• Attention focus (concentration) is hard to maintain for any more than

few seconds. Attention on a task can only be sustained for a short period

of time depending on the specification of the task. Parliamentary Office

of Science and Technology (2001) stated that the figure cited is around

twenty minutes after which, fatigue sets in and errors are more likely to

occur.

• The ability to concentrate depends strongly on the intrinsic capacity of

the current object of attention. Those objects involving personnel danger

such as restricted areas of electric shock from equipment or in power

house; reassembling of parts of equipment abiding, strictly by

instructions and following procedures specified on the working diagram

require high concentration of attention so that the procedure is not

breached.

• Correct performance requires the right balance of attention, neither too

little nor too much (Dunn, 2007). Too much attention results into fatigue

and errors likely to occur. Electrical and electronics maintenance

technicians should imbibe culture of right balance of attention to

minimize occurrence of errors in Nigeria’s manufacturing industries.

The attention system may be influenced by (administrative) information

bottleneck, which is responsible for occurrence of errors. In teamwork, a

technician may be receiving instructions from his supervisor on the services or

repairs being carried out; or glancing at the instructional manuals or observing

results on the display units when doing calibrations. In the process, there may be

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likelihood of the technician not given adequate attention to other aspects of safety

such as electric shock and short circuit.

Attention may be controlled by habits. Habits are behaviours acquired,

perfected and practiced over time as a result of one’s exposure (National Electric

Power Authority then now Power Holding of Nigeria, 1991). Denga (2002)

defined habits as acts or pattern or behaviour that have become so easy through

practice that they occur spontaneously in given situation without conscious thought

or concentrations. Donnelly (1980) noted that when any job is done often enough it

tends to become boring and boredom easily lead careless work.

Maintenance activities in calibrations, testing and monitoring or inspection

are carried out regularly or on daily basis such that they give impression of being

habitual actions. Parliamentary office of science and technology (2001) expressed

that when a task is repeated often enough, it can be done without conscious

supervision, although this automatization of regular and repetitive behaviour can

be a ground for mistakes. The automatization of regular and repetitive behaviour

may mean formation of habits. In maintenance practice, skill workers do particular

job or activity repeatedly. Dunn (2007) explained that there is evidence to suggest

that there is link between the frequency with which a task is performed, and the

likelihood that the task will be performed correctly. Both infrequently performed,

and very frequently performed tasks tend to be those at greatest risk of human

error. Dunn (2007) observed that the skilled and habitual our actions, the less

attention they demand.

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Even though we give adequate attention to events, we do have attention slips.

A worker may be sure that with adequate attention nothing goes wrong with what

he is doing. A technician may cross-check his work, and repeatedly may scan over

an omission with full assurance that everything is undoubtedly correct with his

work or job.

Attention slip is akin to forgetting. Parliamentary Office of Science and

Technology (2001) cited that in 1979 an operator at Oyster Creek Nuclear Power

Plant intended to close off two pump discharge valves; Through an attention slip

he accidentally closed off two other valves as well, and in doing so closed off

circulation to the reactor core. The result of this error was near disaster.

Attention facilitates the encoding and decoding of to-be-remembered

materials by the memory. The to-be-remembered materials are attended to and

selected for the memory to act upon.

Memory: Memory refers to the set of processes by which past experiences

influence present actions (Ruch, 1984). Without memory one can not reflect upon

himself, for the very notion of a self depends on a sense of continuity that only

memory can bring. Many difficulties label memory problems are really attention

lapses” (Hilgard, Atkinson & Atkinson, 1979). One cannot encode what he has not

paid attention to. There are three basic distinctions about memory- the encoding,

storage and retrieval (Ruch, 1984 and Denga, 2002). Information is encoded only

when it is attended to and selected.

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Memory is a storage system with a capacity to withhold short term and long

term experiences at work, home, school and entertainment. Basically, memory is

of two types namely, short-term and long-term memory. The classifications of

memory are based on the difference between those situations that required

materials to be stored for longer interval, say minutes or years. The former

situations are said to reflect short-term memory and the later long-term memory

(Denga, 2002).

Short-term memory has extremely limited capacity (Parliamentary Office of

Science and Technology, 2001). In general people can remember no more than

around seven individual items at a time. Miller in Hilgard, Atkinson and Atkinson

(1979) observed that the capacity of short-term memory is best expressed as 7±2

chunks. The extremely limited capacity of short-term memory has safety

implications in area such as giving new workers a set of instruction to follow from

memory or attempting to remember the correct sequence of procedures within a

new task.

Reason and Hobbs (2003) identified that there are differences between the

capabilities of long term memory and our conscious workspace. The manner and

the rate at which one feels he has the information and therefore knowledge which

can be applied in doing the job at hand is presented by the long term memory. The

information stored for the manner it is presented explains the capabilities of the

long term memory. What is stored is not simply a discrete piece of new

information but a changed pattern of total information, one in which the new piece

becomes part of a new whole (Ruch, 1984).

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The capacity of long-term memory seems virtually unlimited. Luria in Ruch

(1984) expressed that memory experts have memorized large amount of materials

daily without seeming to run out of storage capacity. One’s capacity for

remembering things and the methods one imposes upon himself to access

information often put undue pressure on him (Parliamentary Office of Science and

Technology, 2001). Think of how much is encoded in the memories in a day.

Everything that tells one who he is and what he has done, or even what means to

be anybody is presented in the long-term memory. It includes important

technology systems, procedures, information, related information and unrelated

and irrelevant information, personal information, school subjects, safety rules and

regulations, everyday knowledge about language and social customs and

everything. Ruch (1984) stressed that if any part of it cannot be retrieved one may

be in trouble, not knowing who he is or what year it is, wrong answers on an

examination, calling one person by another’s name, forgetting to keep appointment

and so forth. Even slight errors can cause trouble. There are number of reasons

why recall fails or memory failure occurs. They include lack of adequate attention

given to stimulus. As a result the stimulus is not adequately encoded or not

encoded into long-term memory (Ruch, 1984). Dunn (2007) referred to this as

input failure. It occurs because insufficient attention is paid to be remembered

item.

Usually, item to be stored enters the short-term memory before being passed

onto to long-term memory. Ruch (1984) expressed that information goes from

short-term memory to long-term memory. It is also brought to it when retrieved

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from long-term memory. Information for the long term memory may be lost

through displacement from the short-term memory when the limit of memory span

is reached. After which each new item that enters short-term memory has some

chances of displacing the old one. This results into memory retrieval failure.

Memory failure may be caused by storage failure. In storage, materials to –

be - remembered decay or suffer interference. This results into forgetting (Denga,

2002, Chauhan, 1990 and Hilgard et al, 1979). Hilgard et al (1979) observed that

many cases of forgetting from long-term memory seem to result from loss of

access to the information, rather than from loss of information itself. Anderson

and Faust (1973) in Denga (2002) defined forgetting as the loss in capability to

perform over a period of time during which there is no opportunity to practice.

Chauhan (1990) explained that it is common view that forgetting is a process

of fading with passage of time. Dunn (2007) noted that most common in

maintenance is the problem of forgetting the intention to do something. To this

Fales, Kuetemeyer and Brusic (1993) expressed that it takes one time of

disobeying and forgetting a safety rule for one to be injured. Forgetting may lead

to erroneous acts, accidents or breach of procedure or omission. Under time

pressure, technicians are likely to forget to perform tasks such as replacing nuts

and bolts.

People tend to forget information for other reasons such as emotional

problems and interferences. According to Chauhan (1990) psychologists have

recognized the influence of intervening activities or interferences namely

retroactive inhibition and proactive inhibition. Retroactive inhibition means that

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something works backward to block something else. Proactive inhibition implies

previous materials interfere with the recall of new materials. Technicians may be

under the influence of either retroactive or proactive inhibition while at work.

Forgetting may be caused by retrieval or output failure. One may not be able

to recall things or information he knows at the required time. Chauhan (1990)

explained that forgetting is not like losing something but rather is more like being

unable to find it. Failure to find the item does not necessarily mean it is not there,

it may be looked for in the wrong place or it may simply be misfiled and therefore,

inaccessible. Parliamentary office of Science and Technology (2001) observed that

when items are stored in memory, it is sometimes difficult to access them. Trying

to retrieve item from long term memory requires attending to the item to be

selected. Therefore more attention than before has to be directed to that particular

item felt is required for use. Forgetting occurs because of failure in the mechanism

responsible for remembering.

Forgetting may lead to accidents or breach of application of procedure or

omission. This arises from interruptions in learning to do something such as

repairs or services. The action is rejoined after a sequence of actions having

omitted certain required steps of learning. This makes the segmented materials to

be distorted and difficult to be meaningful.

Many authors’ works including Chauhan’s (1990), Ruch’s (1984) have stated

measures to improve memory. They suggest that items can be best remembered

under the conditions and place, which they were encoded. Parliamentary office of

science and technology (2001) observed that people are more likely to remember

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information if they are in similar conditions to when they encoded the information.

Technicians can visualize the circumstance or condition which affected what they

learnt. This can help them retrieve the lose information.

Another way in which information can be remembered is to learn it at greater

depth. Hilgard et al (1979) explained that if something is to be remembered its

meaning has to be expanded upon. For example, suppose one read a newspaper

article about a mysterious epidemic in San Francisco that health official are trying

to contain. To expand on this, one could, ask himself questions about how officials

could contain the epidemic example: would they just quarantine families with a

deceased member or would they go so far so as to try to stop outsiders from

visiting the city? If the surface features are remembered, them there is a higher

chance of information not being forgotten.

Memory plays major role in human life. Everything that tells one who he is

and what he has done or even what means to be anybody, the decision an

individual takes and logical thinking/reasoning he makes in solving technology

problems is presented by the memory..

Logical Reasoning: Human beings are not very good at thinking logically, but in

technological situations, logical procedures are often necessary. This includes

troubleshooting a complex system which has broken down. Illogical behaviour is a

common source of error in industry (Parliamentary Office and Science and

Technology, 2001). During the Three Mile Island incident in 1979, two valves

which would have been left open were blocked shut. The operators incorrectly

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deduced that they were in fact open, by making an illogical assumption about the

instrument display panel. The display for the valves in question merely showed

that they had been instructed to be open, whereas the operators took this feedback

as indication that they were actually open. Following this all other signs of

impending disaster were misinterpreted with reference to the incorrect assumption

and many attempts to reduce the danger were counter-productive, resulting in

further core damage (Parliamentary Office of Science and Technology, 2001).

Logical reasoning or human thinking is controlled by attention. Beck (1997)

explained that attention is fundamental to human thinking, since it determines the

sources of information that will be considered in many tasks or problems. When

reasoning logically technicians should insulate themselves from distractions and

other interferences that affect their attentions. They should focus attention on

visualized objects and make systematic plans or actions in logical manner.

Working Environment

The modern working environment is very different from the setting that

human have evolved. Manufacturing industries or factories by the nature of their

activities are complex. According to Kara and Collin (1992), the physical

environment of manufacturing industry is described by several parameters:

temperature, noise level and type of noises, lighting level and light characteristics,

and electrical and chemical sources. While some of these factors can either

enhance or degrade performance, others indicate potentially hazardous conditions.

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Sundstrom (1987) defined factory (manufacturing industry) as any facility

devoted to the conversion of raw materials into marketable products.

Manufacturing refers to conversion of organic and inorganic raw materials or

substances into finished or new products by mechanical or chemical means (Ajayi,

2003). Brookstein (2007) explained that there are three main processes involved in

virtually all manufacturing: assembly, extraction, and alteration. According to the

Author assembly is the combination of parts to make a product. For example, an

airplane is assembled when the manufacturer puts together the engines, wings, and

fuselage. Extraction is the process of separating one or more components from raw

materials, such as obtaining gasoline from crude oil. Alteration is modifying or

moulding raw materials into a final product—for example, sawing trees into

lumber.

The means of converting raw materials to marketable products and the

energy conversion from one form to another give rise to by-products which may be

hazardous and safety risks. For instance the combustion of raw materials in the

kiln of cement industry causes release of gases such as ammonia, carbon dioxide

and carbon monoxide. In brewing, ammonia compressors using ammonia gas for

refrigeration of brewed beer can be hazardous, as the release of ammonia gas can

cause body harm. Gases such as carbon monoxide and natural gas are toxic (Riggs,

1981). This type of environment may exist along side with dust (such as in raw and

cement mills). The gases and dusts and smoke may constitute an abnormal

physical environment. Dust and smoke, while not always toxic are disturbing and

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will not be tolerated long without complaint. According to Riggs (1981), many

plants use processes that unavoidably produce unpleasant odours.

The combustion process of kiln in cement industry releases heat. In brewing

for instance there is heat radiation for raising the temperature of black oil and for

boiling the malt. McCormick and Tiffin (1979) explained that environmental heat

has more pronounced effect upon those doing heavy work than those performing

more sedentary activities. Normal daily temperature swings of a degree or two

may cause measurable differences in nervous system functioning (Marshall in

Ruch, 1984). Denga (1996) observed that an excessively hot weather may make

workers not only uncomfortable but may possibly suppress the intellectual

initiative and ingredients or create conditions that are inimical to the maximum

functioning of workers’ abilities. Light from the sun being used as illumination is

good but may have glare. Glare is the most harmful effect of illumination. Glare

from the sun may vary from time to time due to atmospheric conditions. Glare may

also vary with individual. There are two types of glare. They are direct glare and

reflected glare. Direct glare is the glare caused by a light source directly in the

field of vision such as the headlight of an approaching vehicle. Reflected glare is

caused by reflection from a bright surface. According to Riggs (1981) glare can

cause discomfort and affect visual performance. In addition the level and spectral

characteristics of lighting affect the perception of fault indications (Kara & Collin,

1992).

Noise exists on the factory floor. Noise is an unwanted sound. Two aspects of

noise pertain to production. One is the potential loss of hearing that can result from

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continued exposure to very high sound levels. The other aspect is the nuisance

effect that contributes to reduced worker performance. According to Riggs (1981)

there are no definitive levels that bound the regions of good to bad performance or

an exact point where hearing loss develops. Impulse noises interrupt tasks and may

result in skipped or unnecessarily repeated procedures. The level and frequency

characteristics of noise affect the ability to communicate. Workers are likely to be

disturbed by noise from work environment. Noise can upset one’s temperament

and make him less attentive for errors likely to occur. Noise can have other effects

such as serving as a source of annoyance (in communities and homes as well as on

the job) and interfering with communications (McCormick & Tiffin, 1979).

According to Fogarty (2003), many errors result from interacting causes involving

physical, cognitive, social, and organizational factors.

Management Failures: Management may attribute a blame for a major disaster

to a single error made by a fallible process worker. An individual who makes the

final error leading to an accident may simply be the final straw that breaks a

system already made vulnerable by poor management. The organizational

environment, often ignored in the analyses of maintenance systems, has been

shown to be influential in the patterns of work (Dhillon, 1990) and therefore,

possibly in the patterns of errors. Factors which have been identified as important

include: the organization of work groups (or conversely, the isolation of workers),

reporting structures, payoff structures associated with task performance, trust

within one class of personnel, trust between classes of personnel and levels of

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personnel, selection/placement strategies, and human-machine function allocation

of control and responsibility (Kara & Collin, 1992).

Empirical studies of plant operating experience show that human errors are

important contributors to accidents and that, organizational factors play an

important role in creating context for human errors (Ghosh & Apostolakis, 2005).

The findings of studies of many researchers, point to the role social and

organizational factors can have on human error (e.g., Reason, 1990). As these

researchers assert, many errors result from interacting causes involving physical,

cognitive, social, and organizational factors.

In both of the high-profile accidents at the Chernobyl reactor in 1986 and at

the Three-Mile-Island reactor in 1979, detailed root-cause analyses identified

organizational failures as important contributors to the accidents (Ghosh &

Apostolakis, 2005). The authors gave examples of prominent accidents with

organizational root causes in other industries which include the Bhopal chemical

disaster, and the challenger and Columbia space shuttle disasters.

Human decisions and actions play a fundamental role in nearly all accidents

contributing in two main ways, through active and latent failures (Root Cause

Analysis Tool Kit, 2007). Active failures are omissions committed by those at the

sharp end of the system and whose actions can have immediate adverse

consequences (Root Cause Analysis Tool Kit, 2007). According to Parliamentary

Office of Science and Technology (2001), Management of Herald of Free

Enterprise for example put pressure on crews to sail early by sending memos to

staff demanding ships leave fifteen minutes early. Parliamentary Office of Science

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and Technology (2001), narrated that the assistant boson whose job it was to

actually close the doors was asleep in his cabin after maintenance and cleaning

shift. The boson left the deck without checking whether his assistant was on duty

or that the doors had been closed. This mistake caused the vessel to capsize. It is

the management responsibility to ensure that a safe procedure is in place to prevent

any type of omission. According to Root Cause Analysis Tool Kit (2007), such

omissions are influenced by error-provoking conditions (contributory or

influencing factors), such as stress, inadequate training and assessment, poor

supervision or high workload.

Latent failures are created as a result of well intentioned but in hindsight

faulty decisions by senior management (Root Causes Analysis Tool Kit, 2007).

These decisions may have damaging consequences which can lie dormant in the

system for a long time, only becoming evident when they combine with local tasks

and environmental conditions (that is the circumstances which apply when

maintenance is being carried out) to breach the system’s operations. For instance,

the management of The Herald of Free Enterprise’s decision not to act on Ship

master’s request for an estimated four hundred pounds (£400.00) for the bow door

warning indicators be installed on the bridge led to an eventual disaster. The

absence of warning indicators made the ship master to rely on his sense of

judgment which may fail him, which exactly happened.

The safety culture of an organization is the product of the individual and

group values, attitudes, competencies and pattern of behaviour that determine the

style and proficiency of an organization’s health and safety programmes. Positive

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safety culture is one in which shared perceptions of the importance of safety and

confidence in preventive measures are experienced by all levels of an

organizations (Parliamentary Office of Science and Technology, 2001). According

to the Health and Safety Executive (HSE) in Parliamentary Office of Science and

Technology (2001), the statutory body that ensures that risks to Health and Safety

from work activities are properly controlled, and that factors that create positive

culture include:

• a good line management system for managing safety,

• the involvement of all employees,

• effective communication and understood/agreed goals,

• good organizational learning/responsiveness to change,

• manifest attention to workplace safety and health,

• a questioning attitude and rigorous and prudent approach by all

individuals,

If one more of these factors is lacking an organization may be prone to

corner-cutting, poor safety monitoring and poor awareness of safety issues. In

these settings, errors are common and disasters more probable. Parliamentary

Office of Science and Technology (2001), disclosed that it has been found that

workers in poor safety cultures have a ‘macho’ attitude to breaking rules and tend

to ascribe the responsibility of safety to others.

Organizational factors affect tendency to report, confirming that employees

are likely to report mistakes in situations where management is communicative,

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open, and committed to values (Fogarty, 2003). Current work regulation requires

employees to report work accidents (Federal Government of Nigeria, 1990). There

are also some duties under some health and safety law that may lead employers to

investigate accidents and to take account of the lessons learned, but there is no

explicit duty to do so. According to the Health and Safety Council (HSC) in

Parliamentary Office of Science and Technology (2001), many employers do

undertake accident investigation in order to ensure lessons are learned, but this is

not universal and investigation practices vary across industry sectors and types of

business (Parliamentary Office of Science and Technology, 2001).

According to Parliamentary Office of Science and Technology (2001), error

reporting of error investigation depends upon trust between hierarchical levels of

organization and it is suggested that incident reporting is itself an indicator of staff

perceptions of managerial commitment to safety. Failure to document

investigations of errors and accidents is denial to learn from past events and

mistakes.

Surveys demonstrate that short-cuts and work-around do occur in

maintenance work and that, supervisors and managers are aware of these

procedures (Fogarty, 2003). There are undoubtedly practical reasons (for example

time pressure) for these short-cuts but statistical analyses of data collected from

surveys show that there are liable links among violations and errors (Fogarty,

Saunders, & Collyer, 1999 and 2001) and organizational and individual variables

(Fogarty,2003).

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For a disaster to occur there must be a conjunction of oversights and errors

all at different levels within an organization (Parliamentary Office of Science and

Technology, 2001). Failure of management to provide adequate training,

management fatigue-induced errors, effective control of workload and employ

competence assurance in daily running of industrial activities may boost conditions

for errors.

Vigilance Decrement: It is more common for inspector to miss obvious faults the

longer that they have been performing the inspection. This is particularly the case

when the number of hits is few and far between (Dunn, 2007). It is particularly

important to note that sensitivity decrement is found with extended searching time

especially when finding defects are relatively rare event (Good, Nichols,

Subbaram, Nakagawara & Montegomery, 2003).

Failure to follow rules and procedures: Failure to follow a procedure, usually

done for what feels like good reason is not necessarily disastrous on its own,

although it can be. Nigerian Institute of Safety Professionals (2004) listed the

cause of rule breaking to include:

Expectation – the expectation that rules have to be bent to get work done.

Powerfulness - the feeling that one has the ability and experience to do the job

without slavishly following the procedures.

Opportunity - seeing opportunities that present themselves for short-cuts or to do

things better.

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Planning - inadequate work plans, and advance preparation leading to working on

the fly, and solving problems as they arise.

Impact of fatigue: The degree to which fatigue affects an individual can range

from slight to catastrophic. According to Griffith and Mahadevan (2006), the

incidents of Bhopal, Exxon, Valdez, Three Mile Island and Chernobyl list fatigue

as a root cause. Fatigue could be caused by the following factors (Dunn, 2007):

Time of day effects and Stress

Time of day effects: On 12-hour systems the shifts are normally referred to as the

Day and Night shifts, with changes typically taking place at 06:00 to 08:00, and

18:00 to 20:00. Research indicates that night shift may disrupt the natural sleep

and waking cycles of workers’ bodies often referred to as circadian rhythms and

may lead to problems such as high rates of stress, fatigue, job dissatisfaction and

performance errors (Monk, Folkard & Wedderbum,1996, and Zedeck, Jackson &

Marca, 1993). Night shift which disturbs the ‘circadian’ cycle affects the job

performance and also leads to errors. Night shift gives rise to sleep deprivation

which affects reaction time (Griffith & Mahadevan, 2006). Many authors report

that fatigue increases, alertness decreases over the course of night shift (Folkard, et

al, 1996). Both speed and accuracy are decreased in sleep deprived conditions

compared to non-sleep deprived conditions; the evidence is much more conclusive

with respect to speed than accuracy (Griffith & Mahadevan, 2006). Our daily

rhythms ensure that we are more likely to commit errors in the small morning

(Dunn, 2007). However shift related differences in error or accident rates often

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reflect methodological confounders such as the type of work performed and the

workers experience (Folkard, 2007).

Stress: According to Gramling and Auerbach (2008), stress is an unpleasant state

of emotional and physiological arousal that people experience in situations that

they perceive as dangerous or threatening to their well-being. The word stress

means different things to different people. Some people define stress as events or

situations that cause them to feel tension, pressure, or negative emotions such as

anxiety and anger. Others view stress as the response to physiological changes—

such as increased heart rate and muscle tension—as well as emotional and

behavioural changes. However, most psychologists regard stress as a process

involving a person’s interpretation and response to a threatening event.

Stress is a common experience. In maintenance one may feel stress when he is

very busy, has important deadlines to meet, or has too little time to finish all of his

tasks. Often people experience stress because of problems at work or in social

relationships, such as a poor evaluation by a supervisor or an argument with a

friend. Some people may be particularly vulnerable to stress in situations involving

the threat of failure or personal humiliation. Others have extreme fears of objects

or things associated with physical threats—such as snakes, illness, storms, or

flying in an airplane—and become stressed when they encounter or think about

these perceived threats. Major life events, such as the death of a loved one, can

cause severe stress. Stress can have both positive and negative effects. Stress is a

normal, adaptive reaction to threat. It signals danger and prepares one to take

defensive action. Fear of things that pose realistic threats motivates one to deal

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with them or avoid them. Stress also motivates one to achieve and fuels creativity.

Although stress may hinder performance on difficult tasks, moderate stress seems

to improve motivation and performance on less complex tasks.

If not managed appropriately, stress can lead to serious problems. Exposure to

chronic stress can contribute to both physical illnesses, such as heart disease, and

mental illnesses, such as anxiety disorders. Stress may stem from the following

sources. The sources include: Physical factor, Social factor, Drugs, Pace of work

and personal factor.

Physical factor: Denga (1996) stated that septic environments, dangerous gases

inflammable possibilities without corresponding set of protective kit are sources of

stress. Such environment is dreaded by workers, since the possibility of hurting

themselves stares at them whenever they come close to such locations.

Social factor: The state of economic glut and hopelessness is difficult to explain.

Some cases salaries are paid late. Even when workers are paid, salaries purchase

not much. Workers work overtime to make extra money to combat economic

challenges at the expense of their health. “They become fatigue and stressed

because they have little time to rest (Denga, 1996). When a job is done in such a

way that fatigue sets in, errors are likely to occur.

Searching for money to compensate for low take home can be worrisome.

Fogarty (2003) stressed that employees’ resources influence the psychological

strain they feel which is directly responsible for the number of errors they make.

Drugs: During shift or overtime, some workers may take stimulants such as drugs

to keep them awake and alert. Okoro (2000) observed that drugs such as

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amphetamines are stimulants which may make one more alert in driving but often

lead to headache, decreased ability to concentrate and even fatigue. He also

explained that antihistamines are for the relief of nasal congestion and at time as

sleeping aids. The side effects attributed to them include inattention, confusion and

drowsiness. Trying to change the physiological condition stresses the body and

reduces performances

Pace of work: Many workers who are competitive, achievement oriented, working

very hard setting impossible deadlines to finish their physical activity while

sleeping very little often suffer from stress (Denga, 1996). Other activities Denga

(1996) pointed out which are associated with stress include brain work, too much

physical activity such as running, dancing, wrestling, packing one’s property from

one’s house to another, machine operation, writing or processing files, looking for

document and any other activity that takes an unusual length of time to be

executed. This can be stressful and error provoking.

Maintenance work such as sitting or standing to observe or monitor the

operations of indicators on the panel in control room of a factory may induce

fatigue. Though Bryan (1978) expressed that the control room’s panel arrangement

is such that it reduces fatigue however, sitting for a length of periods of time is

stressful as this may overtax the organs, tissues and cells involved in physiological

correlates of internal body, creating room for errors.

Personal factor: Denga (1996) listed psychological factors from which stress is

derived. They include anxiety, depression, compulsive competitive drive to be

ahead of others, negative self evaluation, prolonged emotional trauma, profound

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degree of introversion, neurotic fear of failure or being removed from office, and a

fierce aggression which culminates in a death, wish or desire to inflict injury on

somebody or even kill. Workers who are deprived of love, sense of belonging,

affiliation, self-actualization and who feel insecure in their works may inhibit a

deprivation stress. Hilgard, Atkinson and Atkinson (1979) observed that severe

stress can impair an organism’s immune responses, decreasing its ability to fight

off invading bacteria and viruses. According to Fogarty, Saunders and Collyer

(1999), individual’s morale and health have effect on errors.

Physiological sources and psychological sources of stress are interrelated.

For example, worry is a psychological problem and can give rise to physiological

problem such as peptic ulcers and hypertension (Denga, 1996). He explained that a

strong emotional debility (worry) may express itself in the form of drastic

alteration of physical appearance or even health of individual. Negative emotions

hinder retrieval (Hilgard, Atkinson & Atkinson, 1979). Retrieval failure is an error

in maintenance (Dunn, 2007). The manifestation of emotion among others may

include inattention and aggression (Chauhan, 1990).

Level of arousal: Workers need to be stimulated to put up best performance on the

maintenance job. Deci (1981) stated there are two methods that hold promise for

motivating employees. (i) External reward such as bonus, gifts and awards, using

such a system necessitates making rewards contingent upon performance. Rewards

have to be administered selectively, so that the more effective the receiver’s

performance the more rewards the person receives. But workers may use their

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creativity and devise a means of beating the system by ways of getting larger

rewards for less work. (ii) Intrinsic motivation: Deci (1981) emphasized that the

contingent systems may decrease the intrinsic motivation of workers resulting into

decline in performance and less attention to the job. However, intrinsic motivation

can be achieved through feedback reports or records and competition. It makes

workers to understand themselves and their level of contribution they are making

for sustaining the organization. Deci (1981) explained that with intrinsic system

people motivate themselves out of ego-involvement and a desire to perform

competently.

Bias in thinking and decision-making: There is no such thing as “common

sense”. In particular we are subject to: i, Confirmation bias and ii, Emotional

decision making

i, Confirmation bias:-where we seek information that confirms our initial and

often incorrect diagnosis of a problem (Dunn, 2007)

ii, Emotional decision making: Emotion affects the memory. Forgetting increases

when one is in an emotional state. The individual cannot reason, think and

concentrate on a problem (Chauhan, 1990). Emotion, especially the negative

emotion can hinder performance (Robbins, 2000). When sufficiently tense,

emotions can seriously impair the processes that control organized behaviour

(Hilgard, Atkinson & Atkinson, 1979). Chauchan (1990) stressed that constant

emotional tension may cause lack of sleep, restlessness, headache, chronic fatigue,

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insomnia and lack of appetite. Dunn (2007) observed that intense emotion affect

decision making and may allow errors to occur in maintenance.

If a situation keeps frustrating us, then we tend to move into “aggressive”

mode but this often clouds our better judgment (Dunn, 2007). Emotional decisions

are based on personal relationship with colleagues or past experience such as

change in role and work failures, understanding the equipment one works on, or

having repair and service records of the equipment, and understanding he himself

who works on the equipment to be able to make decision that may yield fruitful

results. Some decisions to repair and service equipment may be frustrating. For

instance when the policy does not fit with the circumstance one is experiencing, so

he has to adapt (Root Cause Analysis Tool Kit, 2007). As a result errors are likely

to manifest.

Work written instructions: procedures are made available to save cost and time.

Procedures is one of the many areas where slight adjustments in current practice

could have a big impact in reducing lost time and money due to human error

(Mather, 2004). Work procedures, however helps to increase the likelihood of

error (Mather, 2004). Mather pointed out how written work procedure may likely

lead to errors as follows:

• Very wordy instructions are often ignored.

• Studies have shown that when there is a long list of instructions those in

the middle are often omitted.

• Too many instructions are ignored as are too few

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• A lot of work instructions are focused on the present, but often there is

need for a re-check of alignment several months afterwards.

• Procedures must not tell how to perform basic skills as they will be

ignored. For example, do not go into detail about how to torque a bolt or

remove the screw. Such instructions may overload attention such that it

may likely lead to error.

Lack of knowledge of particular equipment: Knowledge and skills plays

significant role in maintenance services. Lack of knowledge of particular

equipment plagues any services. There are mistakes in which the individual

encounters a novel situation for which his /her training does not provide some pre-

learned rule-based solution (Root Cause Analysis Tool Kit, 2007). The

consequence is therefore that he/she has to use ad-hoc ‘on line’ reasoning based

upon his/her experience to date. As a result this may lead to error.

Frequent removal and replacement: Mather (2004) observed that there are a

multitude of reasons why human error would occur. These include frequent

removal and replacement of large numbers of varied components often carried out

in cramped and poorly lit spaces with less-than-adequate tools, and usually under

severe time pressure.

Cognitive heuristics: According to Kassin (2006), some researchers have found

that people are prone to forgetting, and worse, that memories of past events are

often highly distorted. Others have observed that people often violate the rules of

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logic and probability when reasoning about real events, as when gamblers

overestimate the odds of winning in games of chance. Kassin (2006) observed that

one reason for these mistakes is that individuals commonly rely on cognitive

heuristics, mental shortcuts that allow them to make judgments that are quick but

often in error.

Other Reasons for Human Error in Maintenance

Human error in maintenance occurs for many reasons. Dhillon (2006)

expressed that some of the important reasons for the occurrence of human error in

maintenance are: outdated maintenance manuals, complex maintenance tasks,

improper work tools, poor equipment design, inadequate training and experience

(qualification), poorly written maintenance procedures, fatigued maintenance

personnel, poor work, humidity, environment, that is, lighting, temperature and

poor work layout.

Qualification of Electrical and Electronics Maintenance Technician

The qualifications of electrical and electronics maintenance technicians

include generally: Educational qualification and years of relevant work

experiences

Educational Qualification: According to Engineering Council of United Kingdom

(UK, 2007), the engineering technicians qualifications include; National

Certificate or National Diploma in Engineering and a technical certificate as part

of an approved Advanced Apprenticeships. The Council for the Regulation of

Engineering of Nigeria (COREN) established under Decree 55 of 1970 and Decree

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27 of 1992 (amended) specifies qualifications for Engineering Technicians as

follows: National Diploma (ND) in Engineering from accredited polytechnics or

monotechnics or Full Technological Certificate (FTC) -Technician qualification)

or Technicians Professional Examination for registered craftsmen

Years of relevant work experience: Qualifications for electrical and

electronics technicians for maintenance employment in process industries also

include; defined number of years of relevant work experiences as specified by

process industries. Process industries such as Armstrong World Industries and

Monitor Systems UK-Scotland-Aberdeen list requirements for qualifications for

the technical or engineering job. This is to enable applicants to compare their

qualifications against the list of requirements. Individuals who possess the

estimated qualifications can compete with other applicants for the unique and

exciting opportunities that define their careers in a challenging and rewarding

field.

Qualification is the interpretation of the estimated capabilities of electrical

and electronics technicians in performing maintenance work in manufacturing

industries. These qualifications for electrical and electronics technicians therefore

form in maintenance the bases which provide for conditions that germinate

maintenance errors. This study is to analyze maintenance errors committed by

individuals working in Nigeria’s Manufacturing Industries with the electrical and

electronics technicians qualifications.

In summary, human characteristics and working environments define the

physiological, psychological, physical factors responsible for human limitations

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and capabilities, implicating management failures for providing context for the

resulting maintenance errors. How human characteristics, working environments

and other factors mediated by management failures to contribute in causing

maintenance errors committed by electrical and electronics maintenance

technicians which give rise to levels of accidents and equipment failures in

Nigeria’s manufacturing industries is subject to investigation by this study.

Frequency of Maintenance Errors

Human beings commit errors almost on regular basis. Franklin (2007)

observed that human make an error on average every sixty seconds. These errors

can be as simple as typing the wrong letter in a word or as serious as driving

through a red light. Usually, the probability of occurrence of human error increases

along with the increase in maintenance frequency as the product or equipment ages

(Dhillon, 2006). Mason (2009) observed that some types of human errors can be so

frequent that they almost become the accepted custom and practice. Civil Aviation

Authority (CAA) Safety Regulation Group (2002) in Pennie, Brook-Carter and

Gibson (2007) unveils that maintenance and inspection procedures are largely

dependent on humans and although no one intends for errors to happen,

psychology informs that humans by nature are prone to error and it is inevitable

that mistakes will be made from time to time.

According to Civil Aviation Authority (CAA) Safety Regulation Group

(2002) in Pennie, Brook-Carter and Gibson (2007), the error rates for example in

complicated non-routine task is 1 error in 10, in routine task with care needed is 1

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error in 100, in routine simple task is 1 error in 1000, and in simplest possible task

is 1 error in 10,000. In 'fail to recognise incorrect status in roving inspection' has

an error rate of 1 in 10. The rate 1 in 10 for error of ‘fail to recognise incorrect

status in roving inspection’ can be interpreted to mean that a person is intentionally

monitoring for a problem and yet misses the obvious 1 times in 10. The last

error—! Fail to act correctly after 1 minute in an emergency situation—9 errors in

10. The rate is high because by two minutes into an emergency situation every

decision people make will be wrong

According to Taylor (2006), in the early 1990s, Boeing conducted a study

of 86 incident reports with respect to maintenance error between 1990 and 1993. It

classified human errors in maintenance into 31 distinct categories. These

categories, along with their corresponding occurrence frequencies in parentheses

are as follows:

System operated in unsafe conditions (16) System not made safe (10)

Equipment failure (10) Towing event (10)

Falls and spontaneous actions (6) Degradation not found (6)

Person entered dangerous area (5) Incomplete installation (5)

Work not documented (5) Person contacted hazard (4)

System not reactivated or deactivated (4) Pin or tie left in place (2)

Unserviceable equipment used (4) Not properly tested (2)

Verbal warning not given (3) Access panel not closed (1)

Vehicle or equipment contacted aircraft (2) Wrong fluid type (1)

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Safety lock or warning removed (2) Panel installed incorrectly (1)

Warning sign or tag not used (2) Incorrect orientation (1)

Vehicle driving (not towing) (2) Contamination of open system (1)

Material left in aircraft or engine (1) Equipment not installed (1)

Wrong equipment or part installed (1) Unable to access part in stores (1)

Required servicing not performed (1) Miscellaneous (6)

Person did not obtain or use appropriate equipment (4)

According to Schreiber (2007), the most frequent errors in maintenance include

‘improper servicing’ (service not performed; system not reactivated/deactivated;

insufficient fluid), ‘improper fault isolation’ (system not properly tested; not

properly inspected) and ‘improper installation’ (incomplete installation; wrong

orientation). Among other types of errors which often occur are ‘general improper

aircraft maintenance due to economic pressure’, ‘incorrect interpretation of

maintenance task or technical manuals’, and ‘damage of aircraft’ (Schreiber,

2007). Other errors are violations.

According to Schreiber (2007), in the opinion of those surveyed, most of

them consider ‘not using the technical documentation’ (for example the Aircraft

Maintenance Manual (AMM) as a violation). This is followed by ‘performing a

maintenance task without a procedure’ and ‘servicing without a checklist’. The

non-compliant actions that have become normal performed necessarily in order to

get a job done. It can be concluded that maintenance person performs a time-

continuous task. Therefore rate of errors made by the maintenance person is

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constant and that errors occur independently. This study is to investigate how

repeatedly errors can be committed by electrical and electronic technicians in

Nigeria’s manufacturing industries

Effects of Maintenance Errors

The maintainers often do not directly see the consequences of their errors.

The effects of these maintenance errors or unsafe acts are significant, impacting

not only on economic performance but also more importantly on public safety as

illustrated by these high profile safety critical events (Pennie, Brook-Carter &

Gibson, 2007).

• 1988 Clapham Rail collision – signal failure caused by uncorrected poor

practices by a signalling technician leading to a wrong-side failure of the

signalling system (a disused wire was allowed to cause a short-circuit);

• 1988 Piper Alpha explosion – maintenance error led to the leak that caused

the explosion, due to a number of technical and organisational failures;

• 1984 Union Carbide Bhopal – a cloud of toxic chemical was released as a

result of operator error, poor maintenance and failed safety systems;

• 2000 Erika – a 25-year-old tanker which broke up and sank off the Brittany

coast, causing one of Europe's worst ever oil spills – contributing factors

included poor organisation of maintenance tasks and procedures, and rule

violations within maintenance tasks.

Effects of maintenance errors are or considered to include accidents and

equipment failures.

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Accidents

Accident is an unintended and unforeseen event, usually resulting in personal

injury or property damage. An accident means an unexpected, undesired, and

unlooked for mishap, or untoward event, connected with the industry in which it

occurs, and which can be reasonably located as to time when and place where it

occurred, causing injury (Kile, 2002). National Electric Power Authority (NEPA)

(1991) defined accident as an unplanned or undesired occurrence arising from

unsafe acts or unsafe conditions which may or may not result to bodily injuries or

damage to property. An accident is an unplanned, undesired event or chain of

events that could lead to personal physical harm, property damage or business

interruption. This physical harm may include traumatic injuries, disease, adverse

mental and neurological effects, resulting from long time exposure to work

environment (Nigerian Institute for Safety Professionals, 2007).

Accidents are not isolated or inevitable occurrences. Each accident appears at

a stage in a process by which some conditions or modes of behaviour lead to an

unplanned result; when suitable and timely adjustment are made, most accidents

can be prevented (NEPA, 1991). Official statistics has shown that no fewer than

3,000 industrial accidents take place in Nigeria annually. However, the unions put

the number at closer to 7000 due to gross under-reporting and under-recording by

2009 (Da Vinci, 2009). Da Vinci (2009) stressed that almost on a daily basis;

various degrees of industrial accidents are recorded, from minor to major injuries

to employees.

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Classes of incidents: Accidents may be classified under incidents. Incidents are

classified according to the degree of damage to personnel or property or none.

Nigerian Institute for Safety Professionals (2004) gave incident classification to

include: Nearmiss, minor accidents and fatal accidents.

According to Nigerian Institute for Safety Professionals (2004), nearmiss is

an incident which potentially could have caused injury or occupational illness

and/or damage (loss) to people, assets, the environment or reputation but which did

not. Minor accidents are accidents that occurred, that have no serious injury, no

loss of life and serious damage to property. Fatal accidents are accidents that

occurred that lead to injury or even death to human being and serious damage to

property.

Singapore Government through the commissioner for Manpower (2000)

classified accidents into three categories. They are:

• Fatal cases;

• Accidents which disable any person from working for more than three

days;

• Accidents causing injury to a person which require him to be

hospitalized for 24 hours and more.

The Federal Government of Nigeria (1990) recognizes the first two classes of

accidents. The Nigeria Factories Act (Cap 126) Section 51 contains the 1st and 2nd

categories of accidents. Section 51: sub-section 1, states that where any accident

occurs in a factory which either:

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• Causes loss of life to a person employed in that factory: or

• Disabled any such person for more than three days from performing

duties for which he may be employed.

• Another classification identified by Adebiyi and Charles-Owaba

includes four types of accidents namely, fatal, serious, minor and

trivial wounds.

The classification of the accidents defines or helps to explain the level of impact of

accidents. In addition, the classification of accidents facilitates process of

investigation which enables the electrical and electronics maintenance technicians

to learn more about causes and perhaps maintenance errors which lead to accidents

in manufacturing industry.

Causes of accidents: Accidents are the result of unplanned deviation in system

operation (Koorneef & Hale, 1997). These deviations initiate an undesired process

which, if not stopped, will lead to an accident (Hendrick & Benner, 1987). It has

been estimated that up to 90% of all workplace accidents have human error as a

cause (Parliamentary Office of Science and Technology, 2001). The Parliamentary

Office of Science and Technology (2001) explained that human error was a factor

in almost all the highly publicized accidents in recent memory, including the

Bhopal Pesticide Plant explosion, Hillsborough football stadium disaster,

Paddington and Southhall rail crashes, Capsizing of the Herald of Free Enterprise,

Chernobyl incident, Three Mile Island incidents and the Challenger Shuttle

disaster.

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Management of information can be source of error. The brains are easily

distracted and can overlook necessary tasks. Omission of steps in maintenance

tasks is cited as a substantial cause of nuclear power plant incident (Parliamentary

Office of Science and Technology, 2001).

According to NEPA (1991), accidents are caused by an unsafe conditions

and unsafe acts due to human failings. According to Root Cause Analysis Tool Kit

(2007), Reason (1993) defines two types of unsafe acts to include errors and

violations. The unsafe acts listed by NEPA (1991) include anxiety, use of wrong

tool, improper maintenance, perceptual difficulties, inadequate skills, improper

handling of work tools, unauthorized operations, disobedience, display of

manhood, worries, distractions/inattentiveness. The unsafe acts also include

inattention, forgetfulness, misperception, failure to follow procedures, inadequate

performance, assuming excessive risk etc (McCormick & Tiffin, 1979). According

to Reason (1990), skill based or unintended, unsafe acts take the form of slips and

lapses, whereas unsafe act involving intended actions can take the form of rule

based or knowledge based mistakes and violations. Violation of safety rules was

found to have resulted into six ocular accidents in Nigerian factories (Abiose &

Otache, 2000).

Accident requires both a hazard and behaviour. The behaviour is an unsafe

act. “Elements of hazardous situations include: 1, the worker 2, the equipment and

3, the environment” (National Electric Power Authority then, now Power Holding

of Nigeria (PHON), 1991). The environment covers occupational hazards such as

air pollution, lighting and noise. National Electric Power Authority then, now

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Power Holding of Nigeria (PHON), (1991) explained that hazards and accidents

may result from a worker’s physical or improper attitude. Workers should be

placed on jobs they can perform safely and supervision should be concerned with

safety and production. NEPA then now PHON (1991) also observed that defective,

improperly maintained or inappropriate equipment must be properly maintained

and made suitable for the job which they are meant. The equipment should meet

safety standards.

Accident may be caused by emotion: An accident may be occasioned by emotion

or worry about something quite remote from the place where the accidents occurs

and from the activity engaged in when the accidents happens. National Electric

Power Authority (NEPA) then, now Power Holding of Nigeria (PHON), (1991)

gave example that a truck driver may be as worried about personal problem as to

ignore a red light. Whether or not the truck collides with another vehicle, the driver

was unsafe. The state of mind was the cause of the unsafe behaviour. In addition,

accident prunes may be increased by tension and preoccupation that are set up in

one person after seeing another involved in an accident.

Dangerous habits may give rise to accidents: Dangerous personnel habits can

result in accident hence industrial losses are not only harmful to the perpetrator,

but also to others close to him. Very dangerous habits are: i, Smoking ii,

Alcoholism, and iii, Drug abuse

i. Smoking: An addicted smoker can extend his smoking habit to prohibited areas

such as offices and work centres. Smoking results in headache, loss of

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appetite, nausea, lung and heart diseases, cancer of the lungs and digestive

organs etc (Guyton & Hall, 1996).

ii. Alcohol: alcohol is a drug which if misused results in physical, psychological

or social damage to the worker or those close to him. The effect alcohol has

on the worker is it changes his sensation, perception, muscle control and

emotions. These changes predispose the worker to accidents as well as

violence. Guyton and Hall (1996) stressed that there are health problems

associated with alcoholism. They are heart problems, liver cirrhosis, mental

illness, loss of memory, brain damage, cancer of the mouth, throat, birth

defects etc.

iii. Drugs: Some drugs are commonly called hard drugs (NEPA then now PHON,

1991). They are, Indian hemp, cocaine, heroin and barbiturates. When they

are taken, they enhance workers performances, proneness to accidents and

lower productivity (NEPA then now PHON, 1991). Amphetamines and other

types of drugs are stimulants which may make one more alert for a short time

but often lead to headache, decreased ability to concentrate and even fatigue

(Okoro, 2000). When fatigue sets in it is likely that error will occur.

According to Dunn (2007) fatigue is a component of error proneness.

Accidents may be caused by person factor: Donnelly (1980) itemized carelessness,

ignorance and skylarking as causes of accidents. Carelessness: when a job is done

often enough, it tends to become boring; such boredom easily leads to careless

work. Ignorance-accidents often occur in industry due to ignorance or inexperience

of workers.

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Accidents may result from anxiety: Anxiety has been listed among the components

which cause accidents. Anxiety however, is brought about by stress which has

psychological consequences. Kahn and Byosiere (1992) expressed that the

psychological consequences of stress include anxiety, depression, burn out,

fatigue, job tension and dissatisfaction with ones job and life. This implies that

stress can lead to accidents and maintenance errors. Dunn (2007) explained that

maintenance error is caused by the impacts of fatigue which could be due to stress.

Accidents may be caused by physical environmental factors: The nature of

physical environment can control accidents rate. “Extremely hot or cold job sites

can result in accidents and low productivity; A work environment which is dusty,

noisy or subject to intense vibration can affect the efficiency of the worker”

(NEPA then now PHON, 1991).

Human decisions and actions play a fundamental role in nearly all accidents

contributing in two main ways, through active and latent failures (Root Cause

Analysis Tool Kit, 2007). Active failures are omissions committed by those at the

sharp end of the system and whose actions can have immediate adverse

consequences. Latent failures are created as a result of well intention but in

hindsight faulty decisions by senior management (Root Causes Analysis Tool Kit,

2007). These decisions may have damaging consequences which can lie dormant

in the system for a long time, only becoming evident when they combine with

local tasks and environmental conditions (that is the circumstances which apply

when maintenance is being carried out) to breach the system’s operations. Based

on the above illustration the causes of accidents are closely linked to sources of

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maintenance error in manufacturing industries. It is therefore necessary that the

electrical and electronics maintenance should study errors, in that ‘reducing

accidents is best achieved by learning from errors’ (Parliamentary Office of

Science and Technology, 2001).

Effects of accidents: Accidents may cause industrial losses. Ezenwa (2001)

reported that between 1987 and 1996, a total of 3,183 injuries as a result of

accidents were reported in Nigerian factories, of which 71 were fatal.

Parliamentary Office of Science and Technology (2001) reported that small scale

workplace accidents account for 200 deaths per year and over 180,000 injuries.

National Safety Council (1996) reported that in every working day there are 17

deaths at workplace. NEPA then now PHON (1991) listed the effects accidents as

follows: Damage to equipment/machines, Injuries to the worker/co-workers, Death

to the worker, reduced productivity and Damage to product etc.

Effects of accidents listed above have economic consequences. Cascio (1998)

in Landy and Conte (2004) observed that thirty-five million workdays are lost each

year as a result of accidents and injuries, resulting in the loss of $40 billion in

wages, as well as medical, administrative and other costs. Riggio (2000) expressed

that the economic costs of the workplace accidents and hazards cover productivity

losses, worker compensation, employee health insurance premiums and medical

treatment. The cost also covers cost of material, spare parts, labour, transportation

and other overhead costs. National Safety Council (1991) explained that Federal

agencies estimate that these combined costs total more than $100 billion annually.

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Kohn, Friend and Winterberger (2004) expressed that although no one can put a

monetary value on a life, each workplace death results in a cost of $780,000 to

United States Society in general. Goetsch (1996) disclosed that workplace deaths

and injuries results in costs of over $48 billion annually.

Accidents may have trans-boundary effects. A reactor at the Chernobyl

power station in Ukraine in the former Soviet Union Republic exploded on 26

April 1986. According to BBC News (2004) the disaster led to dramatic rise in the

number of cases of thyroid cancer, leukaemia and birth defects especially in

Belarus. Up to seven million people are believed to have been affected in what is

the World’s worst nuclear disaster. More than 800 people in Northern Sweden may

have developed cancer as a result of the fallout of the 1986 Chernobyl nuclear

accidents, a new study says”.

Accidents may result in psychological problems such as emotion and trauma.

Adeyemi-Doro (2000) observed that industrial mishaps also cause intentional and

unintentional trauma. Emotional experiences are so traumatic that to allow them to

enter consciousness many years later would cause one to be totally overwhelmed

with anxiety. Holmes in Hilgard, Atkinson and Akinson (1979) noted that anxiety

however does not directly cause memory failure rather it causes or is associated

with extraneous thoughts and these thoughts cause memory failures.

From the above review, accidents are caused by human failings- that is,

errors. Accidents have safety risks and economic consequences. This study will

investigate whether levels of accidents are caused by particular known type of

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maintenance errors committed by electrical and electronics maintenance

technicians in Nigeria’s manufacturing industries.

Equipment Failures

Equipment failure is used synonymously to mean equipment breakdown. It is

the state under working condition which equipment ceases to function due to a

fault or mistake or problem. Equipment is not supposed to fail after they have been

installed. Equipment start up is always a concern because maintenance and

operations spend long hours working to restore equipment availability as soon as

possible. Kirn, Noland and Hauber (2007) stressed that “many times during or

shortly after start-up equipment fails”. The author stressed when investigations are

completed a bearing was installed incorrectly, an impeller was installed

backwards, the wrong lapping compound was used, and list goes on.

Causes of Equipment Failures: Numerous research studies have shown that over

50% of all equipment fails prematurely after maintenance work has been

performed on it (Dunn, 2007). Health and safety executive of the UK in Mather

(2004) states that more than 60% of all maintenance failures had human error as

the root cause, with only 21% representing true engineering failures. Human error

in maintenance continues to be a common cause of asset failure, both in terms of

how an asset is maintained, as well as how it is operated (Mather, 2004). Kirn,

Noland and Hauber (2007) mentioned the following errors as causes of equipment

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failures. They include: Crew turnover, Skill based error, Rule based error and

Knowledge based error.

Crew turnover is the manner which personnel are changed over particular

jobs. The change of personnel can be in form of new employment, or hiring of

labour.

Skill based error may arise from distraction or time pressure. Distraction may

take the form of diverting attention to other taught and becoming doubtful of

certain actions on the job. There may be a kind of mix up. Dunlop (1990) stressed

that the work for every maintenance man is scheduled and conditions are such that

these schedules are met at high percentage of time. This is because production is

tied to time such as unit produced per second or minutes or hour.

Rule based error stems from feedback and reinforcement and communication

error. Dunn (2007) explained that most maintenance work is highly procedural and

consists of many rules. Typical rule based errors include: (i) Misapplying a good

rule or (ii) applying a bad rule (bad habits).

Good quality feedback allows users to judge how effective their actions have

been and what new state the system is in as a result of those actions. An example

of poor feedback occurred during the Three Mile Island incident, a poorly

designed temperature gauge was consistently misread by experienced operators.

They read 2850F as 2350F. This leads them to underestimate the severity of the

situation (Parliamentary Office of Science and Technology, 2001).

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Knowledge based errors; a situation whereby someone is performing an

unusual task for the first time. He is likely to commit error (Dunn, 2007).

Vigilance decrement: This arises from negligence on the part of inspector.

Dunn (2007) observed that it is more common for inspectors to miss obvious faults

the longer that they have been performing the inspection. This is particularly the

case when the number of ‘hits’ is few and far between.

Ignorance: Ignoring to follow the proper guidelines for maintenance services

gives rise to equipment failure. When equipment are left unattended to they may

become corrosive; grease may dry up and rotating part may get stuck, lubricating

oil may become too deteriorating and the degree of wear may increase. The

procedures for maintenance calibrations and testing are often ignored. Mather

(2004), Reason in Dunn (2007) observed that more than half of all identified

performance problems are associated with maintenance, calibration and testing

activities. This is probably because the procedures to follow are often ignored.

Equipment failure can result from design flaw, weak or faulty parts, or a break

accident (Finkelstein & Partners, 2000).

Effects of equipment failures: Stephenson (1999) observed that when breakdown

occurs in industry the following event may take place:

Production capacity is reduced and orders are delayed; there is no production but overhead continues increasing the cost per unit; there are quality issues, products may be damaged; there may be safety issues, employee or customers may be injured (p:758)

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Felton (2001) observed that equipment failure is the leading accident cause.

More than 2,100 workers died and at least 5,000 more were injured in process

industry accidents worldwide in 2000, according to a study by Ility Engineering, a

Finland-based consulting engineering Firm (Felton, 2001). Ninety percent of

accidents occurred during normal maintenance. The immediate cause of 16% of

the incidents was human error.

Equipment failures caused by maintenance errors have obvious safety risks

and economic consequences. The types of errors which cause the equipment

failures with obvious safety risks and economic consequences to make production

capacity unstable are to be investigated by this study.

Theoretical Framework of Maintenance Errors

Analysis of maintenance errors focuses on identifying causal factors in

order to improve the quality of maintenance provided by electrical and electronics

technicians and to prevent hazard and economic consequences in Nigeria’s

manufacturing industries. Mason (2009) noted that human performance can be

affected by many factors such as age, circadian rhythms, state of mind, physical

health, attitude, emotions, propensity for certain common mistakes, errors and

cognitive biases among others. Theories which facilitate or help to conceptualize

maintenance errors committed by electrical and electronics technicians would be

involved in this study. Kerlinger (1986) defined theory as a set of interrelated

constructs and propositions that specify relations among variables to explain and

predict phenomena. Motivation, forgetting and emotion theories involve concepts

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from which facts on human error causation can be inferred while accident and

equipment failure causation theory involve interrelated constructs and propositions

from which the causes of accident and equipment failure can be inferred. Theories

which involve concepts of motivation, forgetting, emotion, accidents/equipment

failures causation and repairs as shown in figure 2

Motivation theories

Accidents/Equipment failures Causation theories

Emotion theories

Human behaviour Maintenance Errors

Forgetting theories

Repair theory

Figure 2 Theoretical Framework of Maintenance Errors

Motivation, forgetting and emotion control human behaviour and are

responsible for errors in maintenance activities. Accident and equipment failure

causation are the results of human actions. Theories which facilitate or help to

conceptualize maintenance errors committed by electrical and electronics

technicians involved in this study include motivation, forgetting, emotion, accident

and equipment failure causation, and repair theories.

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Motivation Theories

Professionals receive a great deal of intrinsic satisfaction from their work.

According to Robbins (2000) professionals have a strong and long term

commitment to their field of expertise. Their loyalty is more often to their

profession than employer. They update their knowledge and show commitment to

their profession. The author explained that what motivates professionals is the job

challenge and support. Motivation theories which offer firm explanation on how to

secure and sustain attention of electrical and electronics technicians on the job

therefore focus on the job challenge and support. They include: Basic need theory,

Reinforcement theory, Goal setting theory, Expectancy Theory and Herzberg’s

theory. The theories of motivation explain how to energize and direct behaviour as

may be expected to maximize performance and reduce maintenance errors in

manufacturing industries.

Hierarchy of need theory: Two basic needs theories are proposed by Abraham

Maslow. Maslow’s theory is called the needs hierarchy theory. The needs theories

maintain that there are several different types of categories of needs that play a role

in human motivation. It proposes that there are five categories of needs, forming a

hierarchy, from basic human needs to more complex higher order needs. The needs

are (1) physiological needs - which include hunger, thirst, shelter, sex, and other

bodily needs; (2) Safety - which includes security and protection from physical and

emotional harm; (3) Social which involves affection belongingness acceptance,

and friendship; (4) Esteem – which covers internal esteem factors such as self

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respect, autonomy and achievement; and external esteem factors such as status,

recognition, and attention; (5) Self-actualization which entails growth, achieving

one’s potential, and self-fulfilment. Safety and social needs are what Maslow calls

“deficiency needs”, which must be satisfied step by step fashion before an

individual can move onto higher order needs, that is esteem and self-actualization

needs - referred to as growth needs. Lower order needs are satisfied externally for

example by pay, union contracts and tenure. Higher order needs are satisfied

internally, that is within the person (Robbins, 2000).

The hierarchy of needs theory emphasizes that although no need is ever

fully gratified, a substantially satisfied need no longer motivates; so if you want to

motivate someone according to Maslow, you need to understand what level of

hierarchy that person is currently on, focus on satisfying those needs at or that

level. This theory has implication on maintenance errors in that if management can

fulfil the needs by providing salaries and wages, good working conditions,

security, fringe benefits, allowing technicians partake in social interactions,

membership groups, have greater responsibilities and high job titles, encouraging

participation among employees and recognizing good performance technicians will

put in their best performance. On the other hand if the needs are not fulfilled or

attainment of needs is thwarted frustration will occur. Going by the theory there

should be no denial of physiological needs to allow technicians have the luxury of

worrying about their personal safety. Safety climate variables are seen as

impacting directly on violations (Fogarty, 2003).

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Reinforcement theory is one of the behaviour-based theories of motivation. The

reinforcement theory emphasizes that behaviour is motivated by its consequences

(Riggio, 2000). A consequence that follows a behaviour and serves to increase the

motivation to perform that behaviour again is a reinforcer. There are two types of

reinforcers -positive and negative reinforcers. Positive reinforcers referred to as

rewards, are events that are in and of themselves desirable to the person. The

reward to electrical and electronics technicians as professionals includes

educational opportunities such as training, attending workshops and conferences to

keep current in their fields. Riggio (2000) expressed that receiving praise, money

or a pat on the back as sign of recognition are all common positive reinforcers.

Negative reinforcers are events that lead to the avoidance of an exciting negative

state or condition. Negative reinforcement increases the motivation to perform the

desired behaviour again in an effort to keep the aversive negative reinforcement

situations from returning. Reinforcement in this context may imply that the

behaviour electrical and electronics technicians engage in at work and the amount

of effort they allocate to each task are affected by the consequences. The

consequences include success and recognition. Recognition can take forms such as

congratulation to employee in private for good job, hand written note, e-mail

message acknowledging something positive that the employee has done, or

publicly recognize accomplishments or celebrate team success. In this way

recognition can boost productivity and minimize errors on the job.

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Goal setting theory: This focuses on job challenge as a means to motivate

workers. The theory emphasizes the role of specific challenging performance goals

and workers’ commitment to those goals as key determinants of motivation

(Riggio, 2000). The theory states that for employees to be motivated goals must be

clear, specific, attainable, and whenever possible quantified. The theory has it that

specific and difficult goal with goal/feedback lead to higher performance

(Robbins, 2000). Specific hard goals produce a higher level of output than the

generalized goals. The specificity of the goal acts as internal stimulus. Also the

more difficult the goal is, the higher the level of performance. Again, people will

do better when they are progressing towards their goals because feedback helps to

identify discrepancies between what they have done and what they have to do; that

is feedback acts to guide behaviour. But all feedbacks are not equally potent. Self-

generated feedback where the employee is able to monitor his or her own progress

has been a more powerful motivator than externally generated feedback.

Robbins (2000) stressed that four other factors have been found to influence

goals-performance relationship namely: goal commitment, adequate self-efficacy,

tasks characteristics and national culture. The goal setting theory presupposes that

an individual is committed to the goal. He is determined not to lower or abandon

the goal. This is most likely to occur when the goals are made public, when an

individual has an internal locus of control and when the goals are self-set rather

than assigned. Self efficacy refers to an individual’s belief that he is capable of

performing a task. The higher the efficacy the more confidence one has in his

ability to succeed in a task. The evidence suggests that goals seem to have a more

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substantial effect on performance when tasks are simple-rather than complex; well

learned rather than novel, and independent rather than interdependent. Goal setting

is culture bound (Robbins, 2000). Riggio (2000) observed that in some countries

such as United States of America employees seek for more challenging goals.

Obviously this is due to better employment conditions which motivate employees

to seek for challenges hence high performance. Other countries such as Chile or

Portugal the employee’s performance is not as high as in United States of America

(USA) which has better employment conditions.

Specific goals facilitate making the structure of task to achieve set goals as

simple as possible. This is because the specific goals or goal-setting provide

direction for carrying out tasks for realizing the specific goals. In this way goal

setting theory can help us to avoid overloading the psychological processes-

attention, perception and memory and subsequent errors in maintenance. By this

theory, maintenance technicians take up appointment as goal commitment. This is

because they feel they are capable of doing the maintenance work well. The results

of their performance hence performance of industry, act as feedback to enable

technicians to improve their performance, thus, resulting to minimal errors.

Expectancy theory: This is a rational theory of motivation. Expectancy theory

states that the motivation to perform a particular behaviour depends on a number

of factors; whether the outcome of the behaviour is desirable (valence), whether

the individual has the ability, skills or energy to get the job done (expectancy), and

whether the performance of the behaviour will indeed lead to expected outcome

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(instrumentality). In other words workers weigh expected costs and benefits of

particular courses before they are motivated to take action. The three core

components of this theory therefore include: valence, instrumentality and

expectancy. Valence refers to the desirability of a particular outcome of an

individual; instrumentality is the perceived relationships between performance of

particular behaviour and the likelihood that a certain outcome will result. In other

words there is a link between one outcome (the worker’s behaviour) and another

outcome (obtaining recognition or a pay rise, for example); expectancy is the

perceived relationship between the individual’s effort and performance of the

behaviour.

Robbins (2000) expressed that the expectancy theory argues that the strength

of a tendency to act in a certain way depends on the strength of an expectation that

the act will be followed by a given outcome and on the attractiveness of that

outcome to the individual. This implies that an employee will be motivated to exert

a high level of effort when he believes that the effort will lead to good

performance appraisal; that a good appraisal will lead to organizational rewards

such as bonuses, salary increase or a promotion, and that the rewards will satisfy

the employees’ personal goals.

At maintenance work, expectancy theory may be applied using avoidance of

supervisors’ displeasure, termination of appointment or dismissal as potential

outcomes. A technician’s goal may be to do an error free job (positive valence) a

flawless job to avoid dismissal from job (expectancy); and avoid having the

organization being displeased with him (instrumentality). In the expectancy theory

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electrical and electronics technicians need to be given autonomy to follow their

interests; and be allowed to structure their work in ways that they find productive.

In this way errors can be minimized.

Herzberg’s two-Factor Theory (Job Design Theories of Motivation): This

deals with the role of job satisfaction in determining workers motivation.

According to the theory, intrinsic factors are related to job satisfaction, while

extrinsic factors are associated with dissatisfaction. Intrinsic factors such as the

work itself, responsibility and achievement seem to be related to job satisfaction. If

people are to be motivated on their job, Herzberg suggested emphasizing factors

associated with the work itself or to outcomes directly derived from it, such as

promotional opportunities, opportunities for personal growth, recognition,

responsibility and achievement should be provided. These are the characteristics

people find intrinsically rewarding (Robbins, 2000).

To motivate technicians intrinsically, jobs need should be set up such that

they are interesting and challenging so as to call forth worker’s creativity and

resourcefulness (Deci, 1992). According to the notion of intrinsic motivation,

workers are motivated by challenges at work, with the reward being the

satisfaction of meeting the challenge of a job well done – that is with little or no

errors.

Extrinsic factors such as supervision, pay, company policies and physical

working conditions, job security and relations with others are related to job

dissatisfaction and are characterized by Herzberg as hygiene factors. The hygiene

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factors are controlled by management of organization. The hygiene factors when

improperly manipulated may become sources of stress which may give rise to

maintenance errors. When the hygiene factors are inadequate they may trigger

industrial crises or psychological problems of anxiety or stress which cause errors

in maintenance work. It shows that to motivate technicians, managers should focus

on the motivators and at the same time try to maintain the hygiene factors at

appropriate level so as to prevent dissatisfaction which likely breeds errors.

Motivation is a process which accounts for an individual’s intensity,

direction, and effort toward attaining a goal. Intensity implies how hard a person

tries. Direction means channelling effort toward benefits. Motivation therefore

involves concentration on the job; that is to direct with exclusive attention upon

the job in the hand. With attention of technicians secured and maintained on the

job occurrence of errors may be minimized in manufacturing industries.

Theories of Forgetting

Traditionally, it is held that people learn by practice and forget because they

failed to practice. Technicians learn technology by practice because it is

embodiment of practical activities. They practice repetitively what they learnt that

is relevant to the work yet they forget to do the right thing and end up making

mistakes. Some theories of forgetting which are relevant to this study of human

error in maintenance activities provide insight as to why forgetting occurs.

According to Chauhan (1990), theories of forgetting are: Theory of decay, Theory

of Interference, Trace change theory and Consolidation theory.

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Theory of decay: This is spontaneous loss of information over time. According to

this theory, impressions created by learning or experience in the cortex fade away

as the time passes (Chauhan, 1990). Chauhan (1990) explained that in our daily

life we have wealth of experiences which fade way with passage of time. We can

meet a man and forget his name after sometime. For information to decay the

following events must take place:

The length of time that elapses between the learning of facts and the recalling them

produce some loss of memory (Chauhan, 1990). Though memories appear to be

resistant to loss with increasingly passage of time, forgetting is greatly influenced

by activities during the retention interval.

What happens between learning and recall? The quality and quantity of

memory however, largely depend on what the learner does while he is having the

experience and what kind of experiences which follow. Decay theory emphasizes

that when something new is learned, a neurochemical, physical "memory trace" is

formed in the brain and over time this trace tends to disintegrate, unless it is

occasionally used (Mcleod, 2008). Technicians learn a lot of information in school

and at work to utilize them when situation makes demands on them. Due to

intervening activities between experiences at school and work and recall,

technicians can not recall everything they learnt or experienced. The theory

implies that due to fading, information can not be recalled at the time the demand

is placed on it. But by rehearsal of tasks, technicians can prevent forgetting that

may result to errors.

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Theory of interference: This deals with intervening activities. This theory holds

forgetting occurs because other information learned earlier or later, interfere with

the memory. The interference may be two types: retroactive inhibition and

proactive inhibition. Retroactive inhibition means information that we learn later

causes a kind of memory barrier that interferes with our remembering previously

learned materials. In proactive inhibition previously learned material interferes

with the recall of present learned materials; that is information that is learned first

interferes with the ability to remember new materials. Financial problems such as

delayed salaries and denial of allowances affect family income and can interfere

with the recall, as one (the mind) pounders in search of solutions to these problems

while doing work. Theory of interference emphasizes that learned materials are

interfered with for example, by the factors mentioned, however by being

committed and anchoring attention on the maintenance jobs technicians can

minimize interference and thus corresponding errors.

Trace change theory: Trace change theory provides evidence that one’s memory

of what he has seen tends to change in a specific way. According to this theory, the

trace laid down by an original experience becomes more perfect and better

balanced figure, thereby losing some of its qualities. This change in the trace

causes us to forget the original figure. Forgetting according to this theory is

attributed to change in traces in the brain. “Bartlett has found that changes in

memory trace are largely influenced by naming or labeling the items to be

memorized” (Chauhan, 1990). Trace decay theory argues that forgetting occurs

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when a memory is not actively used the physical trace between neurons begins to

fade away and may be over-written by new memories. Therefore by actively

accessing a memory, technicians strengthen the trace and the memory should still

be available for any desired maintenance work

Consolidation theory: If the newly formed traces are disturbed and no time is

given for consolidation they will be wiped out. As a result of experience, certain

neural activities responsible for permanent memories are set into motion.

Disruption of these activities leads to poorly formed memories, and thus,

forgetting. Consolidation theory emphasizes the importance of undisturbed period

for maintenance employees –technicians for memory trace to become durable and

permanent so that forgetting does not occur to cause errors.

From the above illustration forgetting is a memory failure which may be

avoidable or unavoidable, and which has been responsible for errors to occur in

maintenance. Technicians should rehearse tasks before they are performed or learn

tasks at greater depth to avoid errors.

Emotion Theory

David Hartley (1705-1757) theory of emotion posits that developed or adult

emotions are the products of elementary feelings uniting, passing into new

connections, and giving rise to complex emotions, under the general law of

contiguity. When emotions are activated such as recalls of incident, they elicit an

adaptive reaction that is experienced by the individual as pleasant or unpleasant

(Papalia & Olds, 1985). Technicians should try to avoid emotion; because under

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emotional state, technicians can not properly reason, think and concentrate on a

problem. In this way error can occur in maintenance activities.

The Lazarus theory of emotion: The Lazarus theory builds on the Schacter-

Singer theory, taking it to another level. It proposes that when an event occurs, a

cognitive appraisal is made (either consciously or subconsciously), and based on

the result of that appraisal, an emotion and physiological response follow. The

Lazarus theory emphasizes that emotions arise based on the value assigned to

certain 'triggers', which are of course, based on personal experiences, and what

those experiences meant to us. Intense emotion, however, should not be allowed to

prolong as it affects decision making and may allow errors to occur in

maintenance.

Accident Causation Theories

Accident causation theories are used to explain how accidents happen. These

theories try to illustrate how potential safety threats referred to as hazards are

translated into injury, loss of life and/or destruction of property known as an

accident. Using these theories, can help to identify some relationships between

maintenance errors and safety, and how maintenance errors can impact plant

safety.

The Domino theory: In 1920, Heinrich studied 75,000 accidents. 88% of

accidents were caused by unsafe acts, 10% by unsafe conditions and 2% are

unavoidable. The Axioms of Domino Theory holds that: Injuries result from a

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completed series of factors, one of which is the accident itself; An accident can

occur only as the result of an unsafe act by a person and/or a physical or

mechanical hazard; Most accidents are the result of unsafe behaviour by people;

An unsafe act by a person or an unsafe condition does not always immediately

result in an accident/injury. However in maintenance activities, attention should

altogether focus on human errors as Heinrich apportioned 88% factor to unsafe

acts and 10% factor to unsafe place / conditions which may also be controlled by

unsafe acts.

Human factors theory: In 1959, Heinrich propounded Human Factors Theory of

Accident Causation. The theory attributes accidents to a chain of events ultimately

caused by human error: Overload, Inappropriate response and Inappropriate

activity; Overload -Environmental Factors (Noise, Distractions), Internal Factors

(Personal Problems, Emotional Stress); Situational Factors (Unclear instructions,

risk level; Inappropriate Response - Detecting a hazard, but not correcting it;

removing safeguards from machines and equipment; ignoring safety and

Inappropriate Activities - Performing tasks without the requisite training,

misjudging the degree of risk involved in a given task. The critical summation is

that technicians have the ability to choose between safe and unsafe acts or

behaviour; and management has the ability to identify the types of human

characteristics and developed work conditions to accommodate them so as to

reduce errors in all maintenance tasks.

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Epidemiological Theory: The key components are the pre-dispositional

characteristics of the worker and the situational characteristics of the job. These

work together to cause or prevent an accident. Maintenance may have a bigger

potential impact on the situational characteristics of the job, but through influence

on the worker, could modify a predisposition to violate operating procedures for

example, override and safeguards.

System Theory: This theory states that there are three main components that

interact in any job: the worker, the machine/equipment, and the environment. The

likelihood of an accident is determined by how these components interact.

However, the elements that interact in the manufacturing process go beyond the

workers and the machines as indicated in the system theory. In combination with

the workers and machines, the other elements that have a great impact on plant

safety are the material being handled in the production process and the method of

production. Four elements have been identified whose interaction in the plant

generates various outcomes. These four elements are referred to as man, material,

machine, and method. The four elements interact with each other in a given

manufacturing environment to give the various outcomes including error incidents.

Accident/Incident theory: It is an extension of Human Error Theory by adding

ergonomic traps and decision to err. This theory also includes system failure as a

cause of accident. Accident/Incident Theory (by Dan Petersen) Overload includes,

pressure, fatigue, motivation, drugs, alcohol and worry. Ergonomic Traps covers

incompatible workstation (i.e., size, force, reach, feel) and incompatible

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expectations. Decision to Err includes misjudgement of the risk, unconscious

desire to err, logical decision based on the situation. Human Error is responsible

for Accident Injury, Damage and Systems Failure associated factors such as

Policy, Responsibility, Training, Inspection, Correction and Standards

Two Central Points of this theory are clear. That injuries are caused by the

action of preceding factors; and removal of the central factor (unsafe act/unsafe

condition) negates the action of preceding factor and, in so doing, prevents

accidents and injuries which may result from maintenance errors.

Repair Theory of Human Error Prevention

The K. VanLehn Repair theory posits that when a procedure (for example in

maintenance tasks) cannot be performed an impasse occurs and the individual

applies various strategies to overcome the impasse. The strategies (meta-action)

are called repairs. Some repairs result in correct outcomes whereas others generate

incorrect results hence “buggy” procedures.

The repair theory is an attempt to explain how people learn procedural skills

with particular attention to how and why they make mistakes (that is bugs). The

repair theory assumes that people primarily learn procedural tasks by induction

and that bugs occur because of biases that are introduced in the examples provided

or the feedback received during practice (as opposed to mistakes in memorizing

formulas and instructions). Therefore the implication of repair theory is that

problem sets should be chosen to eliminate the bias likely to cause specific bugs.

Another implication is that bugs are often introduced when individuals try to

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extend procedures beyond the initial examples provided. According to Brown and

Vanlehn (1980), repair theory applies to any procedural knowledge. This includes

maintenance activities which are embodiment of procedures and rules and which

errors committed can be corrected on time.

From the illustration above theories of emotion, motivation, and forgetting

provide firm foundation for the explanation of the causes of maintenance errors

while human factors - accident causation theory offers explanation on effects of

maintenance errors. The repair theory provides firm foundation for explanation on

how errors may be averted. The explanation provided by these theories deepens

and widens the knowledge on errors which give rise to levels of accidents and

equipment failures, thereby facilitating analysis of errors committed by electrical

and electronics technicians in Nigeria’s manufacturing industries.

Empirical Studies Relevant to the Study of Maintenance Errors

The review of related empirical studies covers empirical studies relevant to

maintenance errors. The empirical studies are as follows:

Fogarty, Saunders and Collyer (1999) conducted a study to explore the role

of individual and organizational variables in maintenance in aviation industry. The

objectives of the study were to; (a) examine a number of organizational, job and

individual factors that were considered likely to impact on maintenance

performance; (b) explore the relations among these variables and (c) develops a

model for predicting important work outcome variables such as turnover

intentions, psychological health and self-reported maintenance errors. A total of

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240 maintenance engineers (232 males) working at the two main helicopter repair

bases for Australia Army responded to the study. Structural equation modelling

was used to develop and test a model linking organizational and individual

variables with self-reported maintenance errors and turnover intentions. The main

features of this model are that; fit indices were accepted; workplace variables

accounted for 40% of variance in health; workplace variables accounted for 58%

of variance in morale; health was the major predictor of maintenance errors,

morale a lesser contributor. Neither job intentions nor work place variables exerted

a direct influence on errors, although workplace variables had a significant indirect

effect through morale and health. This research study is relevant to this study in

the sense that workplace variables as causes of maintenance errors are being

investigated by this study.

Fogarty, Saunders and Collyer (2001) modified slightly the study on

maintenance environment Survey (MES) above and administered to 104

maintenance Army Aviation bases. Four hypotheses were formulated. Structural

equation modelling was sued to develop and test a model linking organizational

and individual variables with self-reported maintenance errors and turnover

intentions. The main features of this model include: fit statistics were within

acceptable limits; the model showed that although workplace variables have a

strong influence on health and morale of employees, the influence of these

variables on errors is entirely indirect. The findings of the study reveal that social

and organizational factors support human error. It is also established that many

errors result from interacting causes involving physical, cognitive, social and

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organizational factors. These factors are considered to be associated with

maintenance errors and subject to investigation by this study.

Fogarty, Saunders and Collyer (2005) conducted a study on the Role of

Individual and Organizational Factors in Aviation Maintenance. A total of 106

maintenance engineers (mostly males) working at one of two main helicopter

repair bases for the Australian Army responded to the survey, representing a

response rate of over 90%. Of the 106 respondents, 48% were tradespersons and

52% trainees. The average age of the respondents was 28.5 years and most (84%)

had been working as a maintenance engineer for at least one year but less than four

years. The statistical tools used were reliability estimates, Pearson Product

Moment correlation coefficient, Structural equation modelling (SEM), using

Arbuckle's (1999) AMOS program (Ver 4.01), and Chi Square of fit. Results

indicated that the findings support the claims of other researchers who point to the

role that social and organizational factors can have on human error (Reason, 1990).

As these researchers assert, many errors result from interacting causes involving

physical, cognitive, social, and organizational factors. The relevance of this

research is due to the fact that the factors mentioned are to be investigated by this

study to find out they are contributors of errors

Fogarty and Neal (2002) conducted a study on the link between safety

climate, stress, maintenance errors and workplace violations. They hypothesized

that management attitudes would exert an indirect influence on violation behaviour

via own attitudes, group norms and perceived control and that group norms would

have a direct effect on own attitudes. Factorial validity and reliability estimates

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were checked using SPSS. Participants in the study included 312 aircraft

maintenance personnel from Australian Army 105, Navy 86, Air Force 116 and 6

civilian maintainers. Survey questionnaire was distributed by staff working for the

Directorate of Flying Safety and returned for analysis. Amos 4.01 (Arbuckle,

1999) was used to test the fit of the path model to the covariance matrix generated

from the safety climate variables. The findings from the study include:

management attitudes have effect either directly or indirectly on all other variables

in the model (the other variables include own attitude, group norms, work

pressure, intention to violate and violation); Group norms affect individual

attitudes, workplace stressors, intention to violate and actual violation; Workplace

stress in not strongly associated with intention to violate and is not linked at all

with actual violations when these other variables are included in the model. This

study is also to investigate whether management or organizational factors

contribute to errors in maintenance.

Fogarty and Neal (2001) conducted a study on violations, errors and

willingness to report. A revised safety climate scale was developed and

administered to 178 maintenance personnel responsible for servicing the Army

Aviation helicopter fleet. The organizational factor was measured by five scales:

Supervision, commitment, communication, management support and training.

Workplace was a much narrower variable than in previous studies, comprising

documentation (manuals, work cards, among others) and adequacy of resources.

The stressors variable was measured by a range of items covering such issues as

time pressures and workload. The model shows that the organizational factors

143

measured by the survey have a direct effect on workplace environment and

violations. Workplace environment, in turn has a direct effect on the stressors

experienced by individual workers. Violations and individual health (which

translates to strain) also have an effect on errors. The organizational factors affect

tendency to report, confirming that employees were more likely to report mistakes

in situations where management is communicative, open and committed to safety

values. This study also is to find out management or organizational factors that are

responsible for errors in maintenance.

Hobbs (2005) conducted a study on the links between errors and errors-

producing conditions in aircraft maintenance. A safety questionnaire was mailed to

all Australian licensed aircraft maintenance engineers, 1359 questionnaire were

returned. 619 usable occurrence reports were received and analyzed to determine

the types of errors that preceded them, and the contributing factors that were

associated with each error form. 96% of occurrences resulted in a whole or in part

from human actions. The occurrences were analyzed using a cognitive error model

and a simple taxonomy of contributing factors. It became apparent that different

cognitive error forms were associated with different contributing factors. Clearly,

safety interventions must take into account the links between errors and their

contexts. The association of errors with their contexts is to be investigated by this

study.

The empirical studies demonstrate that human errors have causal factors

being investigated in maintenance activities. In addition the empirical studies do

not only act as feedback necessary to stimulate actions to avoid errors or serve as

144

proof for occurrence of errors but also help to enrich the literature in study on

maintenance errors in Nigeria’s manufacturing industries.

Summary of Review of Related Literature

In the above review of related literature firm foundations for explanations of

how errors are caused in the maintenance activities are provided by theories of

emotion, motivation and forgetting. Theory of human error effects, and repair

theory provide concrete description of human error as accident/equipment failure

causation and human error prevention respectively.

Errors committed in maintenance activities are differentiated in relation to

three general types of work activities in industry: The work involving discrete acts,

continuous action and monitoring. Monitoring may be referred to as intensive care

of operating equipment for twenty-four hours in manufacturing industry.

Monitoring is akin to inspection which involves comparison of the standard with

the current condition of the equipment to arrive at decisions for choice of any of

the maintenance actions such as calibration, repairs and services. Errors committed

in maintenance activities are classified into types. They include recognition

failures, memory failures, skill-based slips, rule-based mistakes, knowledge-based

errors and violations.

Errors are committed in maintenance via two paths in industry namely,

situational and individual variables. Individual variables operate as human error

causal factors which include vigilance decrement, Failure to follow rules and

procedures, Impact of fatigue, Level of arousal and Bias in thinking and decision-

145

making, Work written instructions, Lack of knowledge of equipment operations

and frequent removal and replacement. Errors which occur in manufacturing

industries give rise to levels of accidents and equipment failures which have

obvious safety risks and economics consequences that affect the stable production

capacity of any manufacturing industries.

The empirical studies related to the study of maintenance errors were

conducted in aviation maintenance. The result from the studies revealed that errors

are caused by human, social, managerial and cognitive factors.

The review of related literature covers causes and effects of human error in

maintenance activities in high risk industries such as aviation, rail, process,

petrochemical and nuclear industries in other countries for example, United States

of America, Norway, United Kingdom and Australia but none in Nigeria including

Nigeria’s manufacturing industries. How often maintenance errors are committed

is also not determined. This study enriches literature on the nature of maintenance

errors by providing on wider scope, information which borders on how often errors

in maintenance are committed, so as to help develop consciousness about the

oftenness of error occurrences in given time. In addition, the study provides

information on causes and effects of errors, and error management in

manufacturing industries with particular reference to electrical and electronics

equipment maintenance in Nigeria situation.

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CHAPTER III

METHODOLOGY

In this chapter the researcher presents the procedure used in carrying out the

study under the following subheadings: Research Design, Area of the Study,

Population for the Study, Sample and Sampling Technique, Instrument for Data

Collection, Validation of the Instrument, Reliability of the Instrument, Method of

Data Collection and Method of Data Analysis.

Design of the Study

The research design adopted for this study is cross - sectional survey.

Electrical and electronic technicians commit errors during maintenance activities

and the supervisors fail to prevent the errors committed at material time resulting

in safety risk and a threat to productive economy. Therefore, a design which would

cut across the different professionals in the maintenance services had to be

established. Thus, cross-sectional design was used as the study involves categories

of maintenance staff such as the electrical and electronics technicians, and

sectional engineers and foremen in their own specific categories referred to as

supervisors; and because data was to be collected from electrical and electronics

technicians and supervisors at one point in time. The collection of data at one point

in time is in line with the observation made by Fraenkel and Wallen (2003) that in

cross-sectional survey

147

design, the information is collected at just one point in time, although the time it

takes to collect all the data desired may take anywhere from a day to a few weeks

or more.

The cross-sectional survey was employed to provide appropriate

investigative information on causes of maintenance errors and levels of accidents

and equipment failures which result from known types of maintenance errors

committed by electrical and electronics technicians in Nigeria’s manufacturing

industries. Understanding the causes of maintenance errors and levels of accidents

and equipment failures which result from known types of maintenance errors

would help identify the type of actions needed to prevent maintenance errors in

Nigeria’s manufacturing industries.

Area of the Study

The area of study is all the thirty-six states of the federation including the

Federal Capital Territory Abuja. Nigeria has Abuja as administrative capital and

Lagos the former capital as commercial seat. Each state of the federation has a

capital with Federal and State Ministries of Commerce and Industry, and

Corporate Affairs Division where manufacturing industries are registered.

Each state capital has a number of large manufacturing industries. However,

the highest concentration of manufacturing industries namely textiles, breweries,

vehicle assembly plants, plastic products, metal processing and fabrics among

others are found in Lagos, Kano, Aba, Port-Harcourt and Kaduna areas. This is

due partly to availability of electricity supply and partly to the market for the

148

products. Revenue mining and availability of raw materials found in rural areas

have resulted into a few major manufacturing industries such as pulp and paper

mills at Oku Iboku and Iwopin, steel mills at Aladja and Ajaokuta, aluminium

smelter at Ikot Obasi, palm oil mills, cement and petrochemical plants. Analysis of

maintenance errors committed by electrical and electronics technicians was carried

out in manufacturing industries located in the thirty-six states.

Population of the Study

The population of the study is 1,163 comprising 745 electrical and

electronics technicians and 418 management representatives which include

electrical and electronics sectional engineers, foremen and electrical and

electronics supervisors, working in manufacturing industries registered with

Industrial Training Fund (ITF) as counterpart trainers. The population of electrical

and electronics technicians and supervisors working in the manufacturing

industries as made available by Federal Ministry of Labour, Employment and

Productivity (2008) in the thirty-six states. The breakdown of the population is

shown in Appendix C on page 233. The electrical and electronics technicians are

the performers of the maintenance tasks with resulting errors while management

representatives referred to by the researcher as supervisors are the immediate key

persons to identify and correct errors committed by electrical and electronics

technicians before they become major problem or stop electrical and electronics

technicians from deviating from the appropriate work procedures. All electrical

and electronics technicians, and supervisors were used for the study of analysis of

149

maintenance errors committed by electrical and electronics technicians in

Nigeria’s manufacturing industries.

Sample and Sampling Technique

A multi-stage cluster sampling procedure was employed to draw a sample

size of 422 respondents (comprising 240 electrical and electronics technicians, and

182 supervisors working in Nigeria’s manufacturing industries). The sample size

was determined using the table for sample size by Research Advisors (2006)

shown in Appendix E on page 236. Clusters or groups of electrical and electronics

technicians, supervisors working in Nigeria’s manufacturing industries were

formed according to the thirty-six states and Abuja, the federal capital. This is in

line with Hubert’s (1980) claim that in cluster sampling, elements are not sampled

directly; instead they are sampled in clusters or groups. However, manufacturing

industries in the Federal Capital were just established and therefore had little or no

information relevant for the study.

Thirty-six clusters of electrical and electronics technicians, supervisors in

manufacturing industries were too large to handle for the study. Random sampling

was employed to select thirty percent of thirty-six states or clusters. Thirty percent

of thirty-six states or clusters with an average of 47 electrical and electronics

technicians, and supervisors per state or cluster is eleven states or clusters. The use

of thirty percent to select sample size is in consonant with Gay’s and Airasian’s

(2003) suggested generalities of table for determining sample size for research

studies: Educational and Psychological Measurement, 30608. To compose a

150

random sample, balloting with replacement procedure was employed to select

eleven states using paper balls. Each paper ball was formed from a paper with a

name of a state written on it and rolled into a shape (of a ball). Balloting with

replacement procedure ensures that each paper ball has equal chances of being

selected; as each paper ball that was picked after thorough mixing of all the paper

balls in a container was dropped back before any other was picked after a thorough

mixing.

Each selected state or cluster has a number of manufacturing industries. Each

manufacturing industry has a number of electrical and electronics technicians and

supervisors employed. Manufacturing industries in states namely, Bauchi and

Plateau among the eleven states selected were rendered unsafe for the study due to

security threat by Boko Haram and crises respectively. In view of the dwindling

number of manufacturing industries due to economic meltdown, management’s

preference for contracting maintenance and the usual lean number of electrical and

electronics technicians and supervisors employed to work on electrical and control

equipment in manufacturing industries, all the electrical and electronics

technicians and supervisors working in the manufacturing industries located in the

selected states constituted the sample of the study. The sample of the study is

shown in Appendix D on page 235.

Instrument for Data Collection

The instrument for data collection is the questionnaire. The questionnaire is

named CHORSLALES after the title of each section of the questionnaire, namely,

151

Causes of maintenance errors, How often errors occur in Repairs and Servicing,

Levels of accidents caused by known types of maintenance errors, Levels of

equipment failure caused by known types of maintenance errors and Strategies for

reducing maintenance errors, using one or two letter(s) of the first word of the

subheading of each section. The questionnaire instrument was used to provide a

quick means of eliciting useful descriptive information or experiences of electrical

and electronics technicians and supervisors on maintenance errors committed by

electrical and electronics technicians in Nigeria’s manufacturing industries.

The questionnaire contained in Appendix B on page 224 was developed after

a thorough review of literature on maintenance error committed in maintenance

activities in industries worldwide. Questionnaire has one hundred and five (105)

items grouped into five sections, A, B, C, D and E.

Section A: This is arranged to evoke information on likely causes of

maintenance errors committed, observed or/and recorded. The

information elicited was used to answer research question 1.

Section B: This is to elicit information on maintenance errors on how often

errors occur in services and repairs. The information collected was

used to answer research questions 2 and 3.

Section C: This is meant to elicit information on level of accident caused by

known types of maintenance errors. The information obtained was

used to answer research question 4.

152

Section D: This is meant to elicit information on level of equipment failure

caused by known types of maintenance errors. The information

obtained was used to answer research question 5.

Section E: This covers strategies adopted to minimize or eliminate maintenance

errors. The information collected was used to answer research

question 6.

Sections A, B and E contain items which were structured using five-point

Likert type scale. The agreement and disagreement response options are separated

by neutral point. The response options are “strongly agree”, “agree”, “undecided”,

“disagree”, and “strongly disagree”. Section B has frequency options “always”,

“most of the time”, “sometimes”, “seldom” and “never”. Sections C and D contain

items which were structured using four-point scale. Its response modes with

respect to condition of equipment and employees include fatal/very serious,

serious, minor and negligible. Subjects (electrical and electronics technicians and

supervisors) were asked to respond to each statement with respect to condition of

employee and equipment, agreement or disagreement on causes and strategies

against maintenance errors, and frequency of recurrences of maintenance errors.

Validation of the Instrument

In order that the questionnaire items measure what it should measure, it was

subjected to face validation by two experts in the Department of Vocational

Teacher Education of the University of Nigeria, Nsukka and one expert from

Benue Breweries, Makurdi. Comment on the clarity, adequacy and appropriateness

153

of the questionnaire items were made in Appendix G on page 238, in response to

request for assistance to validate the questionnaire in Appendix F on page 237.

Based on the comments modification were made in order to produce a final form

of the instrument.

Reliability of the Instrument

To determine the reliability of the instrument, Benue and Gombe States were

chosen for pilot testing. The choice for these States was based on the fact that most

of the manufacturing industries located in these States have unbroken production

and records of events since their inception. The questionnaire forms were then

administered on 20 electrical and electronics maintenance technicians and

supervisors in Benue and Gombe States’ manufacturing industries.

The internal consistency of the instrument was determined using Cronbach

Alpha reliability coefficient formula on the completed questionnaire copies

returned. The computed Cronbach Alpha reliability coefficient σ for sections A, B

and D were as follows: Section A (Causes), 0.90; Section B (How often errors

occur) Repairs, 0.93 and Services, 0.93; and Section E (Enabling strategies), 0.90;

the Reliability coefficient σ for all the completed questionnaire was 0.96 as shown

in Appendix I on page 244. The reliability coefficient σ 0.93 lies between 0.7 and

+1.00. Garson (2008) stated that the common rule of thumb is that to judge the set

of questionnaire items reliable they (indicators) should have a Cronbach alpha

reliability coefficient of 0.7 and above.

154

Method of Data Collection

The researcher with the management of each manufacturing industries that

granted the request contained in Appendix A page 223, administered the

questionnaire to electrical and electronics technicians and supervisors in nine

sample states. In states like Kano, Lagos and Kaduna which have high number of

manufacturing industries the researcher employed the services of industry based

workers/employees in administering copies of the questionnaire. In all a number of

422 copies of the questionnaire were administered in nine states to the respective

technicians and supervisors as shown in detail in Appendix H on page 240.

A total of 375 completed copies of the questionnaire representing 88.86%

were collected by the researcher and industry based workers/employees after two

or three days, from the date the copies of the questionnaire were administered. A

total of 47, that is 11.14% of administered copies were not returned. Certain

factors were responsible for non return of the questionnaire copies. They included

misplacement of the questionnaire copies by respondents and inability of some

respondents on shift duties or assignment elsewhere to send the copies of the

questionnaire in their possession through appropriate persons to either researcher

or respective industry based workers/employees.

Method of Data Analysis

Raw scores from completed questionnaire were generated using primarily

frequency count of responses to each item of completed questionnaire. Data

155

generated were analyzed using mean, standard deviation and t-test of statistical

package for the Social Sciences (SPSS batch system).

Research questions were answered using mean and standard deviation. To

interpret the answer involving mean statistics, each calculated mean value was

compared with the scale values and respective real limits, the lower and upper

limits as shown below

Choice Scaling statement Nominal value Lower limit Upper limit

Agreement Strongly agree 5 4.50 5.00

Agree 4 3.50 4.49

Undecided 3 2.50 3.49

Disagree 2 1.50 2.49

Strongly disagree 1 0.50 1.49

Frequency Always 5 4.50 5.00

Most of the time 4 3.50 4.49

Sometimes 3 2.50 3.49

Seldom 2 1.50 2.49

Never 1 0.50 1.49

Condition Fatal/Very serious 4 3.50 4.00

Serious 3 2.50 3.49

Minor 2 1.50 2.49

Negligible 1 0.50 1.49

Any mean value that lies on or between the lower and upper limit of the scale

values was easily interpreted. For instance a range from 3.50 to 4.49 is meant

156

‘agree’ or most of the time. Cut-off point for mean in five-point Likert scale is

3.00 (aligned with undecided or sometimes). The cut off point is meant to put a

dividing line between agree and disagree or often (always or/and most of the time)

and not often (seldom or/and never). The cut-off point for mean in four- point

scale is 2.00. The four- point cut-off point divides the condition into serious and

not serious

All null hypotheses 1, 2, 3 and 4 were tested at 0.05 levels of significance

using t-test of difference between two means. Mean, standard deviation and t-test

values were presented in appropriate tables to the research questions and

hypotheses. Statistical calculations are contained in Appendix J on page 254.

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CHAPTER IV

PRESENTATION AND ANALYSES OF DATA

This chapter deals with the presentation and analysis of data of the study. The

data collected were analyzed using the procedures described in chapter three. In

analysis the statistics were fully computed and examined as they influenced the

study. The analyzed data were presented in order of the research questions and

hypotheses and where necessary in tabular form. Detailed calculations of statistics

are contained in the appendices.

Research Question 1

What are the likely causes of maintenance errors committed by electrical

and electronics technicians in Nigeria’s manufacturing industries?

Answer to Research Question 1 is presented in Table 1 containing

computed values of mean responses and standard deviation on likely causes of

maintenance errors

158

Table 1

Mean and standard deviation of responses on likely causes of maintenance errors

S/No Causes of maintenance errors c SDc Decision

Human Characteristics

4 Attention paid to a number of tasks at the same time or at once 3.97 1.15 Agree

5 Mind wandered off while performing a routine component change 3.79 1.21 Agree

6 Past experiences nullified the common sense required to make component

change

3.32 1.35 Undecided

7 Items to be remembered were forgotten 3.63 1.24 Agree

8 Difficulties in interpreting signals 3.91 1.16 Agree

9 Necessary tasks were overlooked in routine service or repair process 3.65 1.21 Agree

10 Overconfidence in the information which confirmed the initial and often

incorrect diagnosis of a problem

3.69

1.35

Agree

11 Frustrations at work interfered with judgment required in performing a task 3.69 1.27 Agree

Working Environment

12 Distractions from immediate environment 3.75 1.20 Agree

13 High environmental temperature (heat) suppressed creativity 3.43 1.41 Undecided

14 Darkness affected viewing ability required for efficient performance 3.90 1.34 Agree

15 Noise from immediate environment upset attentiveness 3.63 1.33 Agree

16 Glare affected viewing ability required for efficient performance 3.45 1.31 Undecided

17 Dust polluted environment caused discomfort that affected performance 3.89 1.29 Agree

Management failures

18 Lack of clear work responsibility in order to get job done or achieve targets 4.06 1.14 Agree

19 Excessive provision of incentives and bonuses for meeting targets or

achieving personal goals

2.73

1.54

Undecided

20 Work written instructions without appropriate pictures and graphics provided

for the job

3.29

1.30

Undecided

21 Work written instructions without appropriate conspicuous reminder in order

that critical steps are not omitted were provided for work

3.40

1.29

Undecided

22 Deficient uses of safety analyses 3.86 1.54 Agree

23 Unnecessary burden on employee due to overtime 3.57 1.31 Agree

24 Inadequate implementation of the corrective action plan for identified

problem

3.69 1.25 Agree

(Table continues)

159

S/No Causes of maintenance errors c SDc Decision

Vigilance decrement

25 Sensitivity decreased with extended searching time when defects being

searched for were relatively rare to be seen

3.27

1.27

Undecided

26 Vigilance decreased with time as the number of hits was few and far between

or as faults did not occur after long intervals of time

3.09

1.23

Undecided

Fatigue

27 Excessive work shift hours broken by few hours of sleeps 3.94 1.78 Agree

28 Effects of alcohol taken (previously) on actions 3.88 1.32 Agree

29 Effects of drugs meant to be alert or active on action 3.61 1.29 Agree

30 Influence of social problem (family, money and health) on initiatives 3.91 1.18 Agree

31 Effects of anxiety on actions and intellectual initiatives 3.65 1.17 Agree

32 Stress due to competitive drive to be ahead of others 3.50 1.30 Agree

33 Effects of emotionally charged situations 3.56 1.19 Agree

34 Working hard setting impossible deadlines to finish physical activity while

sleeping very little

3.93

1.27

Agree

Violation of procedures and rules

35 Opportunities presented themselves for short-cut or to do things better 3.41 1.28 Undecided

36 Over demonstration of unnecessary skills to win praise 3.62 1.25 Agree

37 Working on the fly and solving problems as they arise as a result of

inadequate planning and advance preparation

3.46

1.24

Undecided

38 Avoiding what seems to be unnecessary laborious procedure 3.52 1.30 Agree

39 Avoiding what seems to be unnecessary effort to get job done quickly 3.33 1.34 Undecided

40 Expectations that rules have to be bent to get the work done 3.45 1.37 Undecided

41 Well-intended attempts to complete a task in the face of time pressures or

other challenges

3.52

1.26

Agree

Inadequate knowledge and skill

42 Deficient prior knowledge or experience of equipment operations 4.19 1.11 Agree

43 Deficient rehearsal of activities 3.54 1.22 Agree

44 Deficient acquaintance with the job or equipment operations 3.84 1.24 Agree

45 Skills used too often or habitual actions required less attention 3.33 1.34 Undecided

46 Deficient communications and practice for conducting simultaneous

operations in team work

3.93

1.15

Agree

Total 3.58 1.28 Agree

160

Note. c = mean responses on causes of types of maintenance errors.

SDc = Standard deviation of causes of types of maintenance errors

Table 1 shows mean values of items of measure of causes of maintenance errors

which range from 2.73 to 4.19 with standard deviation values ranging from 1.11 to

1.54. The low values of standard deviation indicate that data points in how subjects

responded are variable (hence 1.54-1.11=0.43 about the mean) and tend to be close

to mean responses. Some mean values of items 6, 13, 16, 19, 20, 21, 25, 26, 37, 35,

39, 40 and 45 with standard deviation values ranging from 1.23 to 1.41 lie within

the range from 2.50 to 3.49 for undecided. This might be interpreted to mean that

respondents were not certain whether vigilance decrement and violation of

procedures and rules contributed in causing maintenance errors. However both

electrical and electronics technicians and supervisors shared same experiences that

human characteristics, working environment, management failures, fatigue, and

inadequate knowledge and skills contained in table 1 are the causes of maintenance

errors.

Research Question 2

How often do maintenance errors occur in repair processes in Nigeria’s

manufacturing industries?

Answer to Research Question 2 is presented in Table 2 containing

computed values of mean responses and standard deviation on frequency of

recurrences of errors in repair processes.

161

Table 2

Mean and standard deviation of responses on frequency of recurrences of errors in

repair processes

S/No How often error occurs re SDre Decision

47 Misidentification of objects, signals and messages at material time 3.12 1.20 Sometimes

48 State of problem not detected and equipment started 3.12 1.10 Sometimes

49 Terminating a job before all actions are complete 2.62 1.32 Sometimes

50 Following a specific procedure and deviating to one more familiar when

the intention was not to follow the familiar procedure as was done

2.88

1.17

Sometimes

51 Leaving screws or bolts at ‘finger tight’ rather than properly secured 2.78 1.34 Sometimes

52 Misapplying a good rule where appropriate 2.85 1.44 Sometimes

53 Applying a bad rule to get job done in certain situations 2.78 1.32 Sometimes

54 Removing parts of equipment incorrectly 2.75 1.30 Sometimes

55 Making an untested assumptions as failing to check system before acting 2.76 1.33 Sometimes

56 Forgetting and extending actions beyond the procedure 2.49 1.26 Seldom

57 Driving a screw excessively which cause wear or damage 2.83 1.22 Sometimes

58 Forgetting to tag and/or lock-out unsafe equipment. 2.77 1.08 Sometimes

59 Wounding cable insulations 2.78 1.31 Sometimes

60 Failing to inspect completed tasks physically 2.71 1.31 Sometimes

61 Accepting an unacceptable condition of equipment 2.70 1.40 Sometimes

62 Replacing parts of equipment incorrectly 2.76 1.47 Sometimes

63 Not inspecting during repairs affected components associated with

damaged one

2.77

1.24

Sometimes

64 Not clearing foreign objects which cause short circuit when the job is

completed and equipment energized.

2.76

1.42

Sometimes

65 Not communicating to others when team work is completed and

equipment energized

2.63

1.39

Sometimes

66 Omitting what should be done 2.91 1.42 Sometimes

67 Taking unlikely and inaccurate decisions 2.77 1.37 Sometimes

68 Information, signals and message misinterpreted 3.01 1.36 Sometimes

69 Taking inaccurate measurement or reading 2.85 1.27 Sometimes

70 Forgetting to replace worn and frayed belts on equipment 2.77 1.43 Sometimes

71 Over-oiling motor bearings, resulting in oil being thrown onto insulation

(fire hazard) and onto the floor (fall hazard)

2.80

1.33

Sometimes

Note. re= mean responses of technicians for repair processes

162

SDre = Standard deviation of how often errors occur during repair processes

Table 2 shows values of mean responses ranging from 1.50 to 2.49 for

seldom and from 2.50 to 3.49 for sometimes, and standard deviation from 1.08 to

1.47 on how often errors occur during repair processes. The low values of standard

deviation indicate that data points in how electrical and electronics technicians and

supervisors responded tend to be close to mean responses and as well variable

(1.47-1.08=0.39) about the mean. Item 56 - Forgetting and extending actions

beyond the procedures in repair processes was rarely committed, hence the mean

value of 2.49 for seldom. The span of mean values 2.50 to 3.49 for the rest of the

items may be interpreted to means that at times electrical and electronics

technicians commit errors and supervisors fail to prevent the errors during repair

activities. Interestingly, electrical and electronics technicians rarely forget and

extend their actions beyond procedure, and consequently, supervisors rarely have

the opportunity to prevent extended actions beyond procedure which result in

errors in Nigeria’s manufacturing industries.

Research Question 3

How often do maintenance errors occur in servicing processes in Nigeria’s

manufacturing industries?

Answer to Research Question 3 is presented in Table 3 containing

computed values of mean responses and standard deviation on frequency of

recurrences of errors in servicing processes.

163

Table 3

Mean and standard deviation of responses on frequency of recurrences of errors in

servicing processes

S/No How often error occurs sv SDsv Decision

47 Misidentification of objects, signals and messages at material time 2.87 1.25 Sometimes

48 State of problem not detected and equipment started 2.83 1.18 Sometimes

49 Terminating a job before all actions are complete 2.56 1.37 Sometimes

50 Following a specific procedure and deviating to one more familiar when

the intention was not to follow the familiar procedure as was done

2.73

1.24

Sometimes

51 Leaving screws or bolts at ‘finger tight’ rather than properly secured 2.62 1.36 Sometimes

52 Misapplying a good rule where appropriate 2.66 1.45 Sometimes

53 Applying a bad rule to get job done in certain situations 2.63 1.36 Sometimes

54 Removing parts of equipment incorrectly 2.60 1.30 Sometimes

55 Making an untested assumptions as failing to check system before acting 2.64 1.33 Sometimes

56 Forgetting and extending actions beyond the procedure 2.44 1.29 Seldom

57 Driving a screw excessively which cause wear or damage 2.56 1.23 Sometimes

58 Forgetting to tag and/or lock-out unsafe equipment. 2.66 1.28 Sometimes

59 Wounding cable insulations 2.52 1.28 Sometimes

60 Failing to inspect completed tasks physically 2.54 1.29 Sometimes

61 Accepting an unacceptable condition of equipment 2.58 1.36 Sometimes

62 Replacing parts of equipment incorrectly 2.62 1.46 Sometimes

63 Not inspecting during repairs affected components associated with

damaged one

2.69 1.33 Sometimes

64 Not clearing foreign objects which cause short circuit when the job is

completed and equipment energized.

2.64 1.45 Sometimes

65 Not communicating to others when team work is completed and equipment

energized

2.58 1.34 Sometimes

66 Omitting what should be done 2.70 1.35 Sometimes

67 Taking unlikely and inaccurate decisions 2.59 1.30 Sometimes

68 Information, signals and message misinterpreted 2.78 1.36 Sometimes

69 Taking inaccurate measurement or reading 2.71 1.31 Sometimes

70 Forgetting to replace worn and frayed belts on equipment 2.65 1.39 Sometimes

71 Over-oiling motor bearings, resulting in oil being thrown onto insulation

(fire hazard) and onto the floor (fall hazard)

2.60 1.35 Sometimes

Note. sv= mean responses of technicians for repair processes,

164

SDsv = Standard deviation of how often errors occur in servicing processes

Table 3 shows values of mean responses on how often errors occur in

servicing processes in Nigeria’s manufacturing industries to lie between 2.44 and

2.87 inclusive, and standard deviation values ranging from 1.18 to 1.46. The low

values of standard deviation might mean that data points in how items were

responded not only tend to be close to mean responses but are also variable about

the mean. The range of the mean values falls within the span of seldom from 1.50

to 2.49 and sometimes from 2.50 to 3.49. Item 56-Forgetting and extending

actions beyond the procedure has mean value of 2.44 for seldom. The span of

mean responses values from 2.50 to 3.49 on how often errors occur during

servicing is interpreted to mean that electrical and electronics technicians and

supervisors sometimes are involved in error phenomena during servicing.

Nevertheless electrical and electronics technicians rarely forget and extend actions

beyond procedure in Nigeria’s manufacturing industries.

Research Question 4

What levels of accidents are caused by known types of maintenance errors

committed by electrical and electronics technicians in Nigeria’s manufacturing

industries?

Answer to Research Question 4 is presented in Table 4 containing

computed values of mean responses and standard deviation on levels of accidents

caused by known types of maintenance errors.

165

Table 4

Mean and standard deviation of responses on levels of accidents caused by known

types of maintenance errors

Note. Vsa/fa = Very serious/fatal accident

Sa= Serious accident

S/No Type of Maintenance Errors aaaa SDa Decision

72

Recognition failures committed include errors of

misidentification of objects, signals and messages/non

detection of problem states at material time cause

2.63

1.07

Serious accident

73 Memory failures committed cover errors of failing to

remember items, inability to recall or retrieve items

from memory at material time, omitting certain steps of

sequence following interruptions in sequence of actions

or terminating the job before all actions are complete

lead to

2.50

1.08

Serious accident

74 Skill-based slips committed include branching errors –

following specific procedure but ending up with very

familiar procedure/overshoot errors– following

procedure, forgetting to conclude and making additional

steps to complete the tasks cause

2.38

1.02

Minor accident

75 Rule based mistakes committed cover errors of

misapplying a good rule/applying a bad rule to get the

job done cause

2.73

0.94

Serious accident

76 Knowledge based error committed cover errors of

performing an unusual task for the first time cause

2.75

0.99

Serious accident

77 Violation errors committed cover errors of not

understanding how to apply procedures/acting as not

being aware of procedure/feeling that procedures are

irrelevant/impossible to get job done if procedures are

followed strictly/not adhering to rules to get job done

faster in order to have thrill/failing to follow good

practice when solving problem(s) for the first time cause

2.90

1.00

Serious accident

166

Ma = Minor accident

Na = Negligible accident

Table 4 shows mean values of levels of accidents are caused by known

types of maintenance errors ranging from 2.38 to 2.90 with span of standard

deviation values from 0.94 to 1.08 that cluster around the mean. The mean values

of levels of accidents are caused by known types of maintenance errors committed

by electrical and electronics technicians and their supervisors working in Nigeria’s

manufacturing industries revealed that serious accidents were caused by

recognition failures, memory failures, knowledge based errors, rule-based errors

and violation errors while minor accidents were caused by skill based slips This

is interpreted to mean that technicians and supervisors who perform maintenance

tasks on a daily basis are involved in errors and they are also aware of the errors

that can contribute to various levels of accidents.

Research Question 5

What levels of equipment failures are caused by known types of

maintenance errors committed by electrical and electronics technicians in

Nigeria’s manufacturing industries?

Answer to Research Question 5 is presented in Table 5 containing

computed values of mean responses and standard deviation on levels of equipment

breakdowns caused by known types of maintenance errors

167

Table 5

Mean and standard deviation of responses on levels of equipment breakdowns

caused by known types of maintenance errors

Note. Vsb = Very serious breakdown

Sb = Serious breakdown

Mb = Minor breakdown

S/No Type of Maintenance Errors bbbb SDb Decision

78

Recognition failures committed include errors of

misidentification of objects, signals and messages/non

detection of problem states at material time cause

2.85

0.96

Serious breakdown

79 Memory failures committed cover errors failing to

remember items or inability to recall or retrieve items

from memory at material time or omitting certain steps of

sequence following interruptions in sequence of actions

or terminating the job before all actions are complete

lead to

2.80

0.94

Serious breakdown

80 Skill-based slips committed include branching errors –

following specific procedure but ending up with very

familiar procedure/overshoot errors – following

procedure, forgetting to conclude and making additional

steps to complete the tasks cause

2.58

0.91

Serious breakdown

81 Rule based mistakes committed cover errors of

misapplying a good rule/applying a bad rule to get the job

done cause

2.58

1.07

Serious breakdown

83

Violation errors: committed cover errors of not

understanding how to apply procedures/acting as not

being aware of procedure/feeling that procedures are

irrelevant/impossible to get job done if procedures are

followed strictly/not adhering to rules to get job done

faster in order to have thrill/failing to follow good

practice when solving problem(s) for the first time cause

2.75

1.07

Serious breakdown

168

Nb = Negligible breakdown

Table 5 contains mean values lying between 2.58 and 2.80 with standard

deviation values ranging from 0.91 to 1.07 that cluster closely to the mean on the

responses of electrical and electronics technicians and their supervisors on the

levels of equipment breakdowns caused by known types of maintenance errors.

The data in the table 5 show serious equipment breakdowns to have been caused

by all the known types of maintenance errors, namely recognition failures, skill-

based slips, memory failures, rule-based errors, and knowledge-based errors and

violation errors. The serious equipment breakdowns caused by respective known

types of maintenance errors committed by electrical and electronics technicians

working in Nigeria’s manufacturing industries are interpreted to mean that

technicians and supervisors who perform maintenance tasks on daily basis are

aware of errors which they fail to manage properly, resulting to serious equipment

breakdowns.

Research Question 6

What strategies may be employed in reducing or eliminating maintenance

errors in Nigeria’s manufacturing industries?

Answer to Research Question 6 is presented in Table 6 containing

computed values of mean responses and standard deviation on strategies for

reducing or eliminating maintenance error

169

Table 6

Mean and standard deviation on strategies for reducing or eliminating

maintenance errors

S/No Strategies for reducing or eliminating maintenance errors s SDs Decision

84 Training in error-provoking factors should be provided to maintenance

personnel in order to give them an understanding and awareness of

factors and situations that may lead them to be more error provoking

4.10

1.20

Agree

85 Distractions that are most likely to occur should be controlled 4.33 0.71 Agree

86 Mental rehearsal of tasks before they are performed should be encouraged 4.05 0.99 Agree

87 Measures such as punishment or rehearsal of corrected tasks

to reduce the number of deliberate violations should be implemented

3.70

1.17

Agree

88 Place-markers should be inserted at appropriate points in the procedure to

avoid place-losing errors

3.99

0.99

Agree

89 Teamwork training should be provided to prevent accidents which may

likely occur as a result of poorly functioning teams

4.50

0.73

Strongly

agree

90 Personnel only should perform task when they are properly trained,

skilled and qualified

4.41

0.90

Agree

91 Well designed shift roster should be in place to minimize the impact of

fatigue

4.35

0.86

Agree

92 Adequate control should be put in place for managing over time work 4.29 0.77 Agree

93 Good housekeeping standards should be ensured as housekeeping

practices are good indicator of attitudes and culture relating to quality.

4.39

0.90

Agree

94 Effective maintenance work instructions should be written and use 4.38 0.81 Agree

95 Appropriate use of picture and graphics should be made in work

instructions

4.24

0.93

Agree

96 Appropriate conspicuous reminders in order to ensure that critical steps

are not omitted should be incorporated in works instructions

4.29

0.79

Agree

97 Adequate inspections at key points should be incorporated in the work

instruction

3.96

1.00

Agree

98 Work instruction should be written in clear simple, consistent language

and with the person who is going to use the instruction in mind

4.51

0.71

Strongly

agree

99 Tasks should be assigned appropriately 4.04 1.02 Agree

Table continues

170

Note. s= mean responses of electrical and electronics technicians and their

supervisors on strategies for reducing maintenance errors

SDs = Standard deviation for the strategies for reducing maintenance errors

Table 6 shows mean values of the strategies for reducing maintenance errors

in respect of responses of technicians and supervisors to lie between 3.70 and 4.51

and corresponding standard deviation values ranging from 0.71 to 1.20. The low

standard deviation values indicate that the data points in how subjects responded

are not only variable about the mean but also tend to cluster closely to respective

mean responses. The mean values lie within the span of 3.5 to 4.49 for agreed and

4.5 to 5.00 for strongly agreed. Item 89-Teamwork training should be provided to

prevent accidents which may likely occur as a result of poorly functioning teams

S/No Strategies for reducing or eliminating maintenance errors s SDs Decision

100 Proactive processes for accessing the risk of future maintenance should

be put in place

4.36

0.87

Agree

101 Complex instructions should be grouped into phases, with each phase

consisting of many related tasks

3.89

1.07

Agree

102 Good quality feedback should be provided to allow users to judge how

effective their actions have been and what new state the system is in as a

result of those actions

4.34

0.74

Agree

103 Key risks that may prevent the job from being performed safely and to the

required quality standard should be focused on in the work instructions

4.25

0.85

Agree

104 Hand-held computer with an interactive maintenance checklist which

specifically required the technician to acknowledge that certain stages on

the job had been completed should be employed for work

3.90

1.09

Agree

105 Lessons which may be learned-and remembered from incidents should be

pooled into computerized databases and be searched by key words as part of

risk assessment

4.32

0.76

Agree

Grand total 4.21 0.81 Agree

171

and Item 98 - Work instruction should be written in clear simple, consistent

language and with the person who is going to use the instruction in mind were

strongly agreed upon. In all items, electrical and electronics technicians and

supervisors share the same view and agreed as it is reflected from the very short

range of values of standard deviation.

Test of Hypotheses

All the stated null hypotheses were tested at the P<0.05 level of significance

as follows:

Hypothesis 1

H01: There is no significant difference in mean responses of supervisors and of

electrical and electronics technicians on the likely causes of maintenance errors in

Nigeria’s manufacturing industries

t-test to hypothesis 1 is presented in Table 7 for comparison of mean

responses of electrical and electronics technicians, and of supervisors on causes of

maintenance errors

172

Table 7

t-test comparison of mean responses of electrical and electronics technicians and

of supervisors on causes of maintenance errors

S/No Causes of maintenance errors tc sc t-cal Decision

Human Characteristics

4 Attention paid to a number of tasks at the same time or at once 3.94 4.00 0.53 Not sig

5 Mind wandered off while performing a routine component change 3.78 3.81 0.22 Not sig

6 Past experiences nullified the common sense required to make component

change

3.42

3.20

1.56

Not sig

7 Items to be remembered were forgotten 3.64 3.63 0.04 Not sig

8 Difficulties in interpreting signals 3.91 3.90 0.09 Not sig

9 Necessary tasks were overlooked in routine service or repair process 3.71 3.59 0.92 Not sig

10 Overconfidence in the information which confirmed the initial and often

incorrect diagnosis of a problem

3.69

3.70

0.04

Not sig

11 Persistent frustrating situations at work interfered with judgment required in

performing a task

3.57

3.82

1.95

Not sig

Working Environment:

12 Distractions (signals) from immediate environment 3.78 3.71 0.61 Not sig

13 High environmental temperature (heat) suppressed creativity 3.44 3.42 0.18 Not sig

14 Darkness affected viewing ability required for efficient performance 3.97 3.81 1.18 Not sig

15 Noise from immediate environment upset attentiveness 3.78 3.44 2.49 Sig

16 Glare affected viewing ability required for efficient performance 3.51 3.37 1.08 Not sig

17 Dust and gas polluted the environment and caused discomfort which

affected performance

3.78

4.02

1.75

Not sig

Management failures

18 Lack of clear work responsibility in order to get job done or achieve targets 4.07 4.04 0.28 Not sig

19 Excessive provision of incentives and bonuses for meeting targets or

achieving personal goals

2.81

2.63

1.18

Not sig

20 Work written instructions without appropriate pictures and graphics

provided for the job

3.32

3.25

0.52

Not sig

21 Work written instructions without appropriate conspicuous reminder in

order that critical steps are not omitted were provided for work

3.50

3.28

1.68

Not sig

22 Deficient uses of safety analyses 3.78 3.95 1.41 Not sig

Table continues

173

S/No Causes of maintenance errors tc sc t-cal Decision

23 Unnecessary burden on employee due to overtime 3.61 3.51 0.72 Not sig

24 Inadequate implementation of the corrective action plan for identified

problem

3.66

3.73

0.57

Not sig

Vigilant decrement

25 Sensitivity decreased with extended searching time when defects being

searched for were relatively rare to be seen

3.25

3.29

0.29

Not sig

26 Vigilance decreased with time as the number of hits was few and far

between or as faults did not occur after long intervals of time

3.12

3.06

0.50

Not sig

Fatigue

27 Excessive work shift hours broken by few hours of sleeps 3.95 3.93 0.17 Not sig

28 Effects of alcohol taken (previously) on actions 3.85 3.91 0.39 Not sig

29 Effects of drugs meant to be alert or active on action 3.61 3.62 0.09 Not sig

30 Influence of social problem (family, money and health) on initiatives 3.96 3.86 0.73 Not sig

31 Effects of anxiety on actions and intellectual initiatives 3.56 3.75 1.57 Not sig

32 Stress due to competitive drive to be ahead of others 3.52 3.48 0.33 Not sig

33 Effects of emotionally charged situations 3.54 3.57 0.24 Not sig

34 Working hard setting impossible deadlines to finish physical activity while

sleeping very little

3.92

3.94

0.19

Not sig

Violation of procedures and rules

35 Opportunities presented themselves for short-cut or to do things better 3.35 3.47 0.87 Not sig

36 Over demonstration of unnecessary skills to win praise 3.65 3.60 0.39 Not sig

37 Working on the fly and solving problems as they arise as a result of

inadequate planning and advance preparation

3.41

3.51

0.80

Not sig

38 Avoiding what seems to be unnecessary laborious procedure 3.34 3.44 0.75 Not sig

39 Avoiding what seems to be unnecessary effort to get job done quickly 3.28 3.89 0.77 Not sig

40 Expectations that rules have to be bent to get the work done 3.44 3.46 0.15 Not sig

41 Well-intended attempts to complete a task in the face of time pressures or

other challenges

3.54 3.49 0.36 Not sig

Inadequate knowledge and skills

42 Deficient prior knowledge or experience of equipment operations 4.22 4.15 0.55 Not sig

43 Deficient rehearsal of activities 3.62 3.44 1.41 Not sig

44 Deficient acquaintance with the job or equipment operations 3.74 4.00 1.75 Not sig

45 Skills used too often or habitual actions required less attention 3.24 3.43 1.35 Not sig

46 Deficient communications and practice for conducting simultaneous

operations in team work

3.92

3.94

0.17

Not sig

174

Note. tc= mean responses of electrical and electronics technicians on causes of

maintenance errors

Sig = significant

sc= mean responses of supervisors on causes of maintenance errors

n1= 204,

n2= 171,

df= 373,

t- critical = 1.96

Decision rule:

Reject the null hypothesis where the t-calculated exceeds the t-critical

value; otherwise accept the null hypothesis

Table 7 contains items from number 4 to 46 on causes of maintenance

errors which mean responses were compared using t-test at probability of 0.05

level of significance and 373 degree of freedoms. Item 15 concerning noise from

immediate environment which upset attentiveness showed significant difference in

expressions of electrical and electronics technicians and supervisors hence t-

calculated value was greater than t-critical, and mean difference of 0.34 in favour

of electrical and electronics technicians. The rest of the items had t-ratio calculated

less than the t-critical or table tcal < tcr). This implies that there were no significant

differences in the individual items of measure of causes with respect to expressions

of electrical and electronics technicians and supervisors. Based on the less t-

calculated values, it is good reason to assert that the null hypothesis which states

175

that there is no significant difference between mean responses of electrical and

electronics technicians and supervisors is accepted; and that no differences in

mean ratings had been found significant under causes of maintenance errors except

item 15 which technicians appear to feel more strongly about acceptability than the

supervisors.

Hypothesis 2

H02: There is no significant difference in the mean responses of supervisors and

of electrical and electronics technicians on how often errors occur during

repair processes in Nigeria’s manufacturing industries

t-test to hypothesis 2 is presented in Table 8 for comparison of mean

responses of electrical and electronics technicians, and of supervisors on how often

errors occur in repair processes

176

Table 8

t-test comparison of mean responses of electrical and electronics technicians and

of supervisors on how often errors occur in repair processes

S/No How often error occurs tr sr t-cal Decision

47 Misidentification of objects, signals, messages at right time 3.05 3.20 1.16 Not sig

48 State of problem not detected and equipment started 3.04 3.20 1.41 Not sig

49 Terminating a job before all actions are complete 2.52 2.74 1.56 Not sig

50 Following a specific procedure and deviating to one more familiar when

the intention was not to follow the one more familiar as was done

2.85

2.92

0.26

Not sig

51 Leaving screws or bolts at ‘finger tight’ rather than properly secured 2.61 2.98 2.67 Sig

52 Misapplying a good rule where appropriate 2.73 2.98 1.69 Not sig

53 Applying a bad rule to get job done in certain situations 2.70 2.88 1.29 Not sig

54 Removing parts of equipment incorrectly 2.68 2.83 1.10 Not sig

55 Making an untested assumptions as failing to check system before acting 2.72 2.82 0.75 Not sig

56 Forgetting and extending actions beyond the procedure 2.40 2.61 1.62 Not sig

57 Driving a screw excessively which cause wear or damage 2.74 2.95 1.64 Not sig

58 Forgetting to tag and/or lock-out unsafe equipment. 2.65 2.91 2.28 Sig

59 Wounding cable insulations 2.75 2.81 0.38 Not sig

60 Failing to inspect completed tasks physically 2.72 2.71 0.06 Not sig

61 Accepting an unacceptable condition of equipment 2.72 2.68 0.26 Not sig

62 Replacing parts of equipment incorrectly 2.70 2.83 0.85 Not sig

63 Not inspecting during repairs affected components associated with

damaged one

2.71

2.84

1.43

Not sig

64 Not clearing foreign objects which cause short circuit when the job is

completed and equipment energized.

2.75

2.77

0.18

Not sig

65 Not communicating to others when team work is completed and

equipment energized

2.46

2.84

2.66

Sig

66 Omitting what should be done 2.88 2.94 0.44 Not sig

67 Taking unlikely and inaccurate decisions 2.75 2.78 0.16 Not sig

68 Information, signals and message misinterpreted 2.98 3.04 0.43 Not sig

69 Taking inaccurate measurement or reading 2.76 2.96 1.56 Not sig

70 Forgetting to replace worn and frayed belts on equipment 2.80 2.73 0.50 Not sig

71 Over-oiling motor bearings, resulting in oil being thrown onto insulation

(fire hazard) and onto the floor (fall hazard)

2.74 2.88 1.07 Not sig

177

Note. Sig = Significant

tr= mean responses of electrical and electronics technicians on repair processes

sr= mean responses of supervisors for repair processes

n1= 204, n2= 171, df= 373, t- critical = 1.96

Decision rule:

Reject the null hypothesis where the t-calculated exceeds the t-critical

value, otherwise accept the null hypothesis

In Table 8 differences in mean responses of electrical and electronics

technicians and of supervisors on how often errors occurred during repair

processes were significant only for items 51- Leaving screws or bolts at ‘finger

tight’ rather than properly secured, 58- Forgetting to tag and/or lock-out unsafe

equipment and 65-Not communicating to others when team work is completed and

equipment energized. Supervisors seem to have taken more notice of recurrences

of maintenance errors during repairs than electrical and electronics technicians.

Hypothesis 3

H03: There is no significant difference in mean responses of supervisors and of

electrical and electronics technicians on how often errors occur in servicing

processes Nigeria’s manufacturing industries

t-test to hypothesis 3 is presented in Table 9 for comparison of mean

responses of electrical and electronics technicians, and of supervisors on how often

errors occur in servicing processes

178

Table 9

t-test comparison of mean responses of electrical and electronics technicians and

of supervisors on how often errors occur in servicing processes

S/No How often error occurs rs ss t-cal Decision

47 Misidentification of objects, signals and messages at the right time 2.73 3.04 2.40 Sig

48 State of not detected problem and equipment started 2.75 2.94 1.56 Not sig

49 Terminating a job before all actions are complete 2.50 2.63 0.96 Not sig

50 Following a specific procedure and deviating to one more familiar when

the intention was not to follow the one more familiar as was done

2.69

2.78

0.71

Not sig

51 Leaving screws or bolts at ‘finger tight’ rather than properly secured 2.42 2.86 3.18 Sig

52 Misapplying a good rule where appropriate 2.56 2.78 1.46 Not sig

53 Applying a bad rule to get job done in certain situations 2.59 2.67 0.56 Not sig

54 Removing parts of equipment incorrectly 2.54 2.67 0.99 Not sig

55 Making an untested assumptions as failing to check system before acting 2.59 2.70 0.78 Not sig

56 Forgetting and extending actions beyond the procedure 2.38 2.51 0.99 Not sig

57 Driving a screw excessively which cause wear or damage 2.46 2.69 1.84 Not sig

58 Forgetting to tag and/or lock-out unsafe equipment 2.56 2.69 2.19 Sig

59 Wounding cable insulations 2.43 2.63 1.51 Not sig

60 Failing to inspect completed tasks physically 2.45 2.65 1.52 Not sig

61 Accepting an unacceptable condition of equipment 2.46 2.73 1.88 Not sig

62 Replacing parts of equipment incorrectly 2.52 2.73 1.33 Not sig

63 Not inspecting during repairs affected components associated with

damaged one

2.65 2.73 0.61 Not sig

64 Not clearing foreign objects which cause short circuit when the job is

completed and equipment energized

2.57 2.73 1.04 Not sig

65 Not communicating to others when team work is completed and

equipment energized

2.46 2.73 1.95 Not Sig

66 Omitting what should be done 2.62 2.81 1.36 Not sig

67 Taking unlikely and inaccurate decisions 2.51 2.68 1.30 Not sig

68 Information, signals and message misinterpreted 2.69 2.89 1.44 Not sig

69 Taking inaccurate measurement or reading 2.59 2.87 2.05 Sig

70 Forgetting to replace worn and frayed belts on equipment 2.58 2.73 0.98 Not sig

71 Over-oiling motor bearings, resulting in oil being thrown onto insulation

(fire hazard) and onto the floor (fall hazard)

2.48 2.74 1.92 Not sig

179

Note. Sig = Significant

ts= mean responses of electrical and electronics technicians on frequency of

recurrences of errors in servicing

ss= mean responses of supervisors frequency of recurrences of errors in servicing

n1= 204 technicians, n2= 171 supervisors, df= (n1+n2-2) = 373 and t- critical = 1.96

Decision rule:

Reject the null hypothesis where the t-calculated exceeds the t-critical

value, otherwise accept the null hypothesis

In Table 9 the t-ratio calculated values of items 47- Misidentification of

objects, signals and messages, 51- Leaving screws or bolts at ‘finger tight’ rather

than properly secured, 58- Forgetting to tag and/or lock-out unsafe equipment and

69- Taking inaccurate measurement or reading were greater than t-table value of

1.96. Based on the calculated t-ratio values the mean responses on how often

errors occur during servicing processes errors mentioned are interpreted to be

significant. Supervisors seem to recall more highly about the recurrences of errors

than electrical and electronics technicians. Differences in mean values were found

not significant with the remaining items of Table 9.

Hypothesis 4

HO4: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on levels of accidents caused by known

types of maintenance errors in Nigeria’s manufacturing industries

180

t-test to hypothesis 4 is presented in Table 10 for comparison of mean

responses of electrical and electronics technicians, and of supervisors on levels of

accidents caused by known types of maintenance errors

Table 10

t-test comparison of mean responses on levels of accidents caused by known types

of maintenance errors

Note. at = mean responses of technicians on levels of accidents caused by

known types of maintenance errors

S/No Type of Maintenance Errors atatatat as t-cal Decision

72

Recognition failures committed include errors of misidentification

of objects, signals and messages/non detection of problem states at

material time cause

2.65

2.62

0.28

Not

significant

73 Memory failures committed cover errors of failing to remember

items, inability to recall or retrieve items from memory at material

time, omitting certain steps of sequence following interruptions in

sequence of actions or terminating the job before all actions are

complete lead to

2.62

2.48

0.26

Not

significant

74 Skill-based slips committed include branching errors – following

specific procedure but ending up with very familiar

procedure/overshoot errors– following procedure, forgetting to

conclude and making additional steps to complete the tasks cause

2.38

2.38

0.05

Not

significant

75 Rule based mistakes committed cover errors of misapplying a

good rule/applying a bad rule to get the job done cause

2.70

2.79

0.94

Not

significant

76 Knowledge based error committed cover errors of performing

an unusual task for the first time cause

2.81

2.67

1.42

Not

significant

77 Violation errors committed cover errors of not understanding

how to apply procedures/acting as not being aware of

procedure/feeling that procedures are irrelevant/impossible to get

job done if procedures are followed strictly/not adhering to rules to

get job done faster in order to have thrill/failing to follow good

practice when solving problem(s) for the first time cause

2.88

2.92

0.42

Not

significant

181

as = mean responses of supervisors on levels of accidents caused by known

types of maintenance errors

n1= 204 technicians, n2= 171 supervisors, df= (n1+n2-2)= 373 and t- critical = 1.96

Decision rule:

Reject the null hypothesis where the t-calculated exceeds the t-critical value,

otherwise accept the null hypothesis

Table 10 contains t-test calculated values 0.28, 0.26, 0.05, 0.94, 1.42 and

0.42 lower than the t- critical or table value of 1.96. This can be interpreted to

mean that there is no significant difference in mean responses between electrical

and electronics technicians and supervisors on known types of maintenance errors

being causes of levels of accidents in Nigeria’s manufacturing industries.

Hypothesis 5

HO5: There is no significant difference in the mean responses of supervisors and of

electrical and electronics technicians on levels of equipment breakdowns

caused by known types of maintenance errors in Nigeria’s manufacturing

industries

t-test to hypothesis 5 is presented in Table 11 for comparison of mean

responses of electrical and electronics technicians, and of supervisors on levels of

equipment breakdowns caused by known types of maintenance errors in Nigeria’s

manufacturing industries.

182

Table 11

t-test comparison of mean responses on levels of equipment breakdowns caused by

known types of maintenance errors

S/No Type of Maintenance Errors atatatat as t-cal Decision

78

Recognition failures committed include errors of

misidentification of objects, signals and messages/non

detection of problem states at material time cause

2.86

2.83

0.26

Not

significant

79 Memory failures committed cover errors of failing to

remember items, inability to recall or retrieve items from

memory at material time, omitting certain steps of

sequence following interruptions in sequence of actions

or terminating the job before all actions are complete

lead to

2.83

2.76

0.78

Not

significant

80 Skill-based slips committed include branching errors –

following specific procedure but ending up with very

familiar procedure/overshoot errors– following

procedure, forgetting to conclude and making additional

steps to complete the tasks cause

2.52

2.66

1.44

Not

significant

81 Rule based mistakes committed cover errors of

misapplying a good rule/applying a bad rule to get the

job done cause

2.53

2.65

1.13

Not

significant

82 Knowledge based error committed cover errors of

performing an unusual task for the first time cause

2.81

2.59

1.97

Not

significant

83 Violation errors committed cover errors of not

understanding how to apply procedures/acting as not

being aware of procedure/feeling that procedures are

irrelevant/impossible to get job done if procedures are

followed strictly/not adhering to rules to get job done

faster in order to have thrill/failing to follow good

practice when solving problem(s) for the first time cause

2.75

2.74

0.10

Not

significant

183

Note. bt = mean responses of electrical and electronics technicians on levels of

equipment breakdowns caused by known types of maintenance errors

bs = mean responses of supervisors on levels of equipment breakdowns

caused by known types of maintenance errors

n1= 204 technicians, n2= 171 supervisors, df = 373 and t- critical = 1.96

Decision rule:

Reject the null hypothesis where the t-calculated exceeds the t-critical value,

otherwise accept the null hypothesis

Table 11 contains t-test calculated values 0.26, 0.78, 1.44, 1.13, 1.97 and

0.10 lower than the t- critical or table value of 1.96. This can be interpreted to

mean that there is no significant difference in mean responses between electrical

and electronics technicians and supervisors on known types of maintenance errors

being responsible for levels of equipment breakdowns in Nigeria’s manufacturing

industries.

Hypothesis 6

H06: There is no significant difference between mean responses of electrical and

electronics technicians, and of supervisors on the strategies to reduce or to

eliminate maintenance errors in Nigeria’s manufacturing industries.

t-test to hypothesis 6 is presented in Table 12 for comparison of mean

responses of electrical and electronics technicians, and of supervisors on strategies

to reduce or eliminate maintenance errors.

184

Table 12

t-test comparison of mean responses on strategies to reduce/eliminate

maintenance errors

S/No Strategies for reducing or eliminating errors tttt s t-cal Decision

84 Training in error-provoking factors should be provided to maintenance

personnel in order to give them an understanding and awareness of factors and

situations that may lead them to be more error provoking

4.14 4.04 0.81 Not Sig

85 Distractions that are most likely to occur should be controlled 4.25 4.42 2.19 Sig

86 Mental rehearsal of tasks before they are performed should be encouraged 4.02 4.08 0.56 Not sig

87 Measures such as punishment or rehearsal of corrected tasks

to reduce the number of deliberate violations should be implemented

3.73 3.67 0.56 Not sig

88 Place-markers should be inserted at appropriate points in the procedure to

avoid place-losing errors

3.97 4.02 0.56 Not sig

89 Teamwork training should be provided to prevent accidents which may likely

occur as a result of poorly functioning teams

4.52 4.47 0.67 Not sig

90 Personnel only should perform task when they are properly trained, skilled and

qualified

4.40 4.43 0.27 Not sig

91 Well designed shift roster should be in place to minimize the impact of fatigue 4.28 4.44 1.79 Not sig

92 Adequate control should be put in place for managing over time work 4.30 4.27 0.37 Not sig

93 Good housekeeping standards should be ensured as housekeeping practices are

good indicator of attitudes and culture relating to quality.

4.38 4.40 0.16 Not sig

94 Effective maintenance work instructions should be written and use 4.34 4.44 1.19 Not sig

95 Appropriate use of picture and graphics should be made in work instructions 4.25 4.23 0.22 Not sig

96 Appropriate conspicuous reminders in order to ensure that critical steps are not

omitted should be incorporated in works instructions

4.32 4.26 0.68 Not sig

97 Adequate independent inspections at key points should be incorporated in the

work instruction

3.98 3.94 0.33 Not sig

98 Work instruction should be written in clear simple, consistent language and

with the person who is going to use the instruction in mind

4.40 4.64 3.31 Sig

99 Tasks should be assigned appropriately 4.01 4.07 0.52 Not sig

100 Proactive processes for accessing the risk of future maintenance should be put

in place

4.24 4.51 3.08 Sig

101 Complex instructions should be grouped into phases, with each phase

consisting of many related tasks

3.82 3.98 1.42 Not sig

Table continues

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S/No Strategies for reducing or eliminating errors tttt s t-cal Decision

102 Good quality feedback should be provided to allow users to judge how

effective their actions have been and what new state the system is in as a result

of those actions

4.29 4.40 1.35 Not sig

103 Key risks that may prevent the job from being performed safely and to the

required quality standard should be focused on in the work instructions

4.23 4.27 0.44 Not sig

104 Hand-held computer with an interactive maintenance checklist which

specifically required the technician to acknowledge that certain stages on the

job had been completed should be employed for work

3.80 4.01 1.88 Not sig

105 Lessons which may be learned-and remembered from incidents or equipment

failures should be pooled into computerized databases and be searched by key

words as part of risk assessment

4.24 4.43 2.44 Sig

Note. t= mean responses for electrical and electronics technicians on strategies.

s= mean responses for supervisors on strategies.

Sig = Significant

n1= 204,

n2= 171,

df= 373 (n1+n2-2),

t- critical = 1.960

Decision rule:

Reject the null hypothesis where the t-calculated exceeds the t-critical

value; otherwise accept the null hypothesis

Items 85, 98, 100 and 105 shown on Table 12 have t-calculated values of -

2.19, -3.31, -3.08 and -2.44 in order of items. Each of these t-calculated values is

greater than t-table 1.96. It therefore means that there is significant difference in

the mean responses for the items 85- Distractions that are most likely to occur

should be controlled, 98- Work instruction should be written in clear simple,

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consistent language and with the person who is going to use the instruction in

mind, 100- Proactive processes for accessing the risk of future maintenance should

be put in place, and 105- Lessons which may be learned-and remembered from

incidents or equipment failures should be pooled into computerized databases and

be searched by key words as part of risk assessment of the strategies to reduce or

eliminate maintenance errors in Nigeria’s manufacturing industries. Differences

exist because supervisors appear to feel more strongly about the acceptability of

the suitability of the items than the technicians. Difference in mean responses was

found not significant with the rest of the items of the enabling strategies to reduce

or eliminate maintenance errors as the table reflects t-calculated values in each

case less than t-critical.

Major Findings

The following are summaries of major findings of the study:

1. Electrical and electronics technicians and supervisors were statistically

undecided on items of measure of causes 6, 13, 19, 20, 21, 25, 26, 34, 35,

39, and 45 of Table 1 on maintenance errors in Nigeria’s manufacturing

industries

2. Electrical and electronics technicians and supervisors quite agree on the rest

of the items of measure of causes of maintenance errors not mentioned in

number 1 above; that indices of Human characteristics, working

environments, management failures, fatigue, inadequate knowledge and

skills, and violations of procedures and rules are responsible for the known

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types of maintenance errors committed by electrical and electronics

technicians in Nigeria’s manufacturing industries.

3. Vigilance decrement was statistically undecided upon by electrical and

electronics technicians and supervisors to contribute to causes of

maintenance errors in Nigeria’s manufacturing industries

4. All other items of maintenance errors apart from item 56 Forgetting and

extending actions beyond the procedure of Table 2 occur at times in repair

processes in Nigeria’s manufacturing industries.

5. All other items except item 56 Forgetting and extending actions beyond the

procedure of Table 3, occur at times in servicing processes in Nigeria’s

manufacturing industries

6. Maintenance error of (item 56 -) Forgetting and extending actions beyond

the procedure rarely occur during servicing processes in Nigeria’s

manufacturing industries

7. Maintenance error of (item 56 -) Forgetting and extending actions beyond

the procedure rarely occur during repair processes in Nigeria’s

manufacturing industries

8. Serious accidents are caused by recognition failures, memory failures, skill

based mistakes, rule based errors, knowledge based errors and violation

errors in Nigeria’s manufacturing industries

9. Minor accidents are caused by skill-based mistakes in Nigeria’s

manufacturing industries

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10. Serious equipment breakdowns are caused by all the known types of

maintenance errors in Nigeria’s manufacturing industries

11. Electrical and electronics technicians and supervisors quite strongly agree

on items of measure 89 and 98 of Table 6 of strategies to be useful in

reducing or eliminating maintenance errors in Nigeria’s manufacturing

industries.

12. Electrical and electronics technicians and supervisors do not statistically

differ significantly in their responses on levels accidents and equipment

breakdowns errors in Nigeria’s manufacturing industries

13. Electrical and electronics technicians and supervisors quite agree on the rest

of the items of measure on Table 6 for strategies to be useful in reducing or

eliminating maintenance errors in Nigeria’s manufacturing industries.

14. Electrical and electronics technicians and supervisors do not statistically

differ significantly in their experiences on causes of maintenance errors,

except item 15- Noise from immediate environment upset temperament and

attentiveness of Table 7

15. Electrical and electronics technicians and supervisors do statistically differ

significant in their experiences on item 15 of causes of maintenance errors

on Table 7 which technicians appear to feel more strongly about

acceptability than the supervisors.

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16. Electrical and electronics technicians and supervisors do not differ

significantly in their experiences on how often errors occur during repair

processes except items 51, 58 and 65 of Table 8.

17. Electrical and electronics technicians and supervisors differ significantly in

their experiences with respect to item 51- Leaving screws or bolts at ‘finger

tight’ rather than properly secured of Table 8 concerning how often errors

occur during repair processes in Nigeria’s manufacturing industries.

18. Electrical and electronics technicians and supervisors differ significantly in

their experiences with respect to item 58- Forgetting to tag and/or lock-out

unsafe equipment on how often errors occur during repair processes in

Nigeria’s manufacturing industries.

19. Electrical and electronics technicians and supervisors differ significantly in

their experiences with respect to item 65- Not communicating to others

when team work is completed and equipment energized on how often errors

occur during repair processes in Nigeria’s manufacturing industries.

20. Electrical and electronics technicians and supervisors do not differ

significantly in their experiences in twenty-one of the twenty-five items on

how often errors occur servicing processes in Nigeria’s manufacturing

industries.

21. Electrical and electronics technicians and supervisors differ statistically

significant in their experiences on item 47- Misidentification of objects,

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signals and messages at material time of Table 9 concerning how often

errors occur in servicing processes.

22. Electrical and electronics technicians and supervisors differ statistically

significant in their experiences on item 51- Leaving screws or bolts at

‘finger tight’ rather than properly secured of Table 9 concerning how often

errors occur in servicing processes

23. Electrical and electronics technicians and supervisors differ statistically

significant in their experiences on item 58- Forgetting to tag and/or lock-out

unsafe equipment of Table 9 concerning how often errors occur in servicing

processes

24. Electrical and electronics technicians and supervisors differ statistically

significant in their experiences on item 69- Taking inaccurate measurement

or reading of Table 9 concerning how often errors occur in servicing

processes

25. Differences in opinions of electrical and electronics technicians and

supervisors on strategies for reducing or eliminating maintenance errors

with respect to item 85-Distractions that are most likely to occur should be

controlled of Table 12 were significant

26. Differences in opinions of electrical and electronics technicians and

supervisors on strategies for reducing or eliminating maintenance errors

with respect to item 98-Work instruction should be written in clear simple,

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consistent language and with the person who is going to use the instruction

in mind of Table 12 were significant

27. Differences in opinions of electrical and electronics technicians and

supervisors on strategies for reducing or eliminating maintenance errors

with respect to item 100-Proactive processes for accessing the risk of future

maintenance should be put in place of Table 12 were significant

28. Differences in opinions of electrical and electronics technicians and

supervisors on strategies for reducing or eliminating maintenance errors

with respect to item 105-Lessons which may be learned-and remembered

from incidents or equipment failures should be pooled into computerized

databases and be searched by key words as part of risk assessment of Table

12 were significant

29. The opinions of technicians and supervisors do not differ significantly on

the 18 items of Table 12 for strategies for reducing or eliminating

maintenance errors in Nigeria’s manufacturing industries.

Discussion of the Findings

The discussion of the findings of this study is discussed under sub-headings based

on the six specific objectives of the purpose of the study. The specific objectives

are phrased as follows: Causes of maintenance errors, Oftenness of recurrences of

maintenance errors during repairs, Oftenness of recurrences of maintenance errors

in servicing processes, Levels of accidents caused by known types of maintenance

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errors, Levels of equipment failures caused by known types of maintenance errors

and Strategies for reducing or eliminating maintenance errors

Causes of maintenance errors: The first point raised under the purpose of the

study is the causes of maintenance errors in Nigeria’s manufacturing industries.

The findings of the study indicate that human characteristics, working

environment, management failures, fatigue, inadequate knowledge and skills and

violations of procedures and rules are contributing factors to maintenance errors

committed by the electrical and electronics technicians in Nigeria’s manufacturing

industries (see Table 1). Human characteristics are characterized by attention,

perception, memory and reasoning or decision making and were measured by

items 4 - 46 of Table 1. The findings of the study derived from the items 4 - 46 are

in consonant with the assertion made by parliamentary office of Science and

Technology (2001) that there are a number of reasons why attention system is

responsible for errors, the claims made by the Parliamentary Office of Science and

Technology (2001) regarding perception that the interpretation of senses can be in

error, also the claim by Kasin (2006) that one reason individuals make mistake is

reliance on mental short-cut or cognitive heuristic that allows them to make

judgments that are quick but often incorrect, furthermore, the notice taken by Dunn

(2007) that the most common in maintenance is the problem of forgetting the

intention to do something. Items 12 to 17 measured the working environment. The

items of measure cover distraction, ambient temperature, lighting system and air

pollution. The findings of this study find working environment to be responsible

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for the maintenance errors committed by the electrical and electronics technicians.

Specifically the findings of the study in relation to noise distraction support

Cohen’s (1972) findings on the noise level involving 500 workers that distractions

heighten the psychological stress responsible for errors. The findings of this study

regarding lighting system support the claim that the level and spectral

characteristics of lighting affect the perception of fault indications (Kara & Colin,

1992). Furthermore the findings of this study confirm environment as a situational

variable mentioned by Reason and Hobbs (2003) as one of the paths which cause

maintenance errors in factories.

Management failure is measured by six items. Each of the items constitutes

the findings of the study in relation to management failures. The findings of the

study in relation to management failures support the claims of other researchers

who point to the role organizational factors can have on human error ( Reason,

1990). According to Reason (1990), these researchers assert, many errors result

from interacting causes involving physical, cognitive, social, and organizational

factors. The findings of the study in relation to management failures also support

the claim made by Ghosh and Apostolakis (2005) that organizational factors play

an important role in creating context for human error in maintenance –maintenance

errors.

The findings of this study on vigilance decrement reveal that vigilance

decrement was statistically undecided on to be responsible for the maintenance

errors in Nigeria’s manufacturing industries. However Dunn (2007) observed that

vigilance decrement takes place particularly in the case when the number of hits is

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few and far between. The findings of the study on sensitivity decrement also reveal

that sensitivity decrement was also statistically undecided on to be responsible for

the known types of maintenance errors in Nigeria’s manufacturing industries

though Good, Nichols, Subbaram, Nakagawara and Montegomery (2003) observed

that sensitivity decrement is found with extended searching time especially when

finding defects are relatively rare event. Vigilance decrement therefore is relatively

least known to contribute to maintenance errors in Nigeria’s manufacturing

industries

The finding of this study with respect to fatigue measured by 8 items reveal

that fatigue contributes immensely in causing maintenance errors in Nigeria’s

manufacturing industries. Items 27 to 34 focus on time of the day effects and stress

induced variously. Based on the items of measure, the findings of the study

support the claim made by Dunn (2007) that our daily rhythms ensure that people

are more likely to commit errors in the small hours of the morning. The findings of

the study regarding physical, social, drugs, pace of work and personnel factors are

supported by observation made by Dunn (2007) that they are the sources of

maintenance errors The findings of the study (items 30 and 35) is in consonant

with the assertion by Fogarty (2003) that the employees resources influence the

psychological strain they feel which is directly responsible for the number of errors

they make. The findings of the study also is a confirmation of claims made by

Dunn (2007) and Reason (2003) that stress is a source of error in maintenance. The

findings of this study on these particular indicators are in support to the assertion

195

that work place has a direct effect on the stressors experienced by individual

worker (Fogarty & Neal, 2002).

The findings of this study in relation to violations of procedures and rules

that procedures are violated (see items 35 to 41 of Table 1) is in line with claims

made by Fogarty (2003) that there is a link between violations and errors in

maintenance. The findings of the study regarding inadequate knowledge and skills

structured on items 42 to 46 of Table 1 support the confirmatory remarks made by

Root cause Analysis (2007) that there are mistakes in which individual encounters

a novel situation for which his/her training does not provide some pre-learned rule

based solutions.

Electrical and electronics technicians and supervisors are completely

satisfied with the causes of maintenance errors and do not differ significantly in

their acceptability of items of measure of causes of errors except item 15 of the

items of measure. Electrical and electronics technicians and supervisor differ

significantly in their experiences of causes of maintenance errors as measured by

item 28 on noise distraction. The significant difference is because electrical and

electronics technicians appear to feel more strongly about the acceptability of the

item 15 of Table 7.

Frequency of recurrences of maintenance errors during repairs: Second issue

raised under the purpose is how often maintenance errors occur during repair

processes measured by items 47 to 71 of Table 2. All maintenance errors except

error item 69 occur at times in Nigeria’s manufacturing industries during the repair

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processes. The findings of the study support the assertion made by Dunn (2007)

that more than half of errors in maintenance are recognized as having happened

before – often many times. The findings of the study support Civil Aviation

Authority (CAA) Safety Regulation Group (2002) on frequency of occurrences of

errors during repairs regarding Fail to act correctly after 1 minute in an emergency

situation of 9 errors in 10. The findings of the study agrees with the claim made by

Schreiber (2007) that the most frequent errors in maintenance include ‘improper

fault isolation’ (system not properly tested; not properly inspected) following by

‘improper installation’ (incomplete installation; wrong orientation). Among other

types of errors which often occur are ‘general improper aircraft maintenance due to

economic pressure’, ‘incorrect interpretation of maintenance task or technical

manuals’, and ‘damage of aircraft’ (Schreiber, 2007). Other errors are violations.

All the respondents’ experiences were pooled together to make comparison

on how often errors occur during repair processes. Differences in mean responses

of technicians and supervisors were significant for item 64- Leaving screws or

bolts at ‘finger tight’ rather than properly secured, 71- Forgetting to tag and/or

lock-out unsafe equipment and item 78- Not communicating to others when team

work is completed and equipment energized. Supervisors seem to be more

assertive about commonness of recurrences errors during repair processes than the

electrical and electronics technicians for the above item. Supervisor being more

assertive is based on the fact that the rate of errors made by the maintenance

person is constant and that errors occur independently.

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Frequency of recurrences of maintenance errors in servicing processes: The

third point raised under the purpose is how often maintenance errors occur during

servicing processes in Nigeria’s manufacturing industries. The findings of the

study are in consonance with the claims by Civil Aviation Authority (CAA) Safety

Regulation Group (2002) in Pennie, Brook-Carter and Gibson (2007) concerning

the rates error occurs. According to Civil Aviation Authority (CAA) Safety

Regulation Group (2002) in Pennie, Brook-Carter and Gibson (2007), the rates, for

example in complicated non-routine task is 1 error in 10, in routine task with care

needed is 1 error in 100, in routine simple task is 1 error in 1000, and in simplest

possible task is 1 error in 10,000. The findings of the study is supported by the

observation made by Civil Aviation Authority (CAA) Safety Regulation Group

(2002) in Pennie, Brook-Carter and Gibson (2007) that maintenance and

inspection procedures are largely dependent on humans and although no one

intends for errors to happen, psychology informs that humans by nature are prone

to error and it is inevitable that mistakes will be made from time to time. The fact

is that maintenance and inspection work is also commonly performed in difficult

working conditions, and often under time pressure. To this end, Pennie et al (2007)

noted that James Reason, a leading authority on human error, commented that if an

evil genius was given the job of creating an activity guaranteed to produce an

abundance of errors they would devise something akin to maintenance work.

The findings of the study further upholds the claim made by Schreiber

(2007), that the most frequent errors in maintenance include ‘improper servicing’

(service not performed; system not reactivated/deactivated; insufficient fluid),

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According to Schreiber (2007), in the opinion of those surveyed most of them

consider ‘not using the technical documentation’ (for example the Aircraft

Maintenance Manual - AMM) as a violation). This is followed by ‘performing a

maintenance task without a procedure’ and ‘servicing without a checklist’. The

non-compliant actions that have become normal performed necessarily in order to

get a job done.

Information gathered from personnel managers and sectional engineers of

various Nigeria’s manufacturing industries by researcher tend to support the

findings of the study. According to the personnel managers and sectional

engineers, maintenance errors actually occur often in inspection in factories as an

aspect of human error but are managed or controlled.

Differences in mean responses between electrical and electronics technicians,

and supervisors on how often errors occur during servicing processes are found to

be significant with the following items 60-Misidentification of objects, signals and

messages at material time, 64-Leaving screws or bolts at ‘finger tight’ rather than

properly secured, 71-Forgetting to tag and/or lock-out unsafe equipment and 69-

Taking inaccurate measurement or reading Supervisors seem to have noticed more

recurrences of mentioned errors than electrical and electronics technicians.

Levels of accidents caused by known types of maintenance errors: The fourth

point raised is the levels of accidents caused by the known types of maintenance

errors in Nigeria’s manufacturing industries. The findings of the study with respect

to the levels of accidents caused by the known types of maintenance errors reveal

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that recognition failure, memory failures, rule based mistakes, and knowledge

based errors and violation errors caused accidents at serious level while skill based

slips caused minor accidents. The findings of the study that maintenance errors

lead to accidents is reminiscent of the claim made by Health and Safety Executive

(HSE) (2008) concerning accidents caused by maintenance errors that even

experienced, highly-trained, well-motivated technicians can make simple slips and

omissions, and such errors can initiate major accidents, as well as result in

personal injury to maintenance personnel. The findings of this study are in

consonant with the assertion accredited to Health and Safety Executive (HSE)

(2008) that many accidents and incidents have maintenance error as root cause or

major contributory cause. Furthermore, the findings of this study are the

confirmations of the accident causation theory that accidents are caused by human

error; hence maintenance error is a discrete form of human error. The findings of

this study stand as proof that types of maintenance errors cause various degrees of

accidents in Nigeria’s manufacturing industries as elsewhere in the world. The

findings of this study support the claims by many authors that four types of

accidents, namely, fatal, serious, minor and trivial wounds are identified in

Nigeria’s manufacturing industries by Charles-Owaba and Adebiyi, (2009), and

two types of accidents, for example loss of lives and injuries in Nigerian factories

as reported by Ezenwa (2001). Almost on a daily basis, various degrees of

industrial accidents are recorded, from minor to major injuries to employees (Da

Vinci, 2009). Violation of safety rules was found to have resulted into six ocular

accidents in Nigerian factories (Abiose & Otache, 2000). Also statistics has shown

200

that the most common cause of all workplace accidents (minor or major) is

employee error (OSHA, 2010). Employee error in this context implies

maintenance error in relation to equipment reliability.

No accident, no matter how obvious its causal factors seem to be, ever occurs

in isolation. Human error which is responsible for accidents in manufacturing

industries has been managed; lessons learned from past errors have had impact on

maintenance system, however, there is still room for improvement.

Levels of equipment failures caused by known types of maintenance errors:

The fifth issue reacted upon is the levels of equipment breakdown caused by the

known types of maintenance errors committed by electrical and electronics

technicians in Nigeria’s manufacturing industries. The findings of this study

indicate that equipment failures caused by the known types of maintenance errors

were at serious level. The findings of the study are analogous to the assertions

made by Kirn, Noland and Hamber (2007) that skill based error, rule based error

and knowledge based errors cause equipment failures. The findings of this study in

relation to equipment failures caused by the known types of maintenance errors in

Nigeria’s manufacturing industries is confirmatory to assertion made by Matter

(2004) concerning the cause of equipment failures that maintenance error (human

error in maintenance) continues to be a common cause of asset failures both in

terms of how an asset is maintained as well as how it is operated and also

reminiscent of equipment failure causation theory that equipment failures are

caused by human errors.

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Strategies for reducing or eliminating maintenance errors: The last issue raised

focuses on the strategies for reducing or eliminating maintenance errors. Items of

measure included items 84 to 105 of Table 6. All the respondents registered their

agreement for the strategies as means for reducing or eliminating maintenance

errors in Nigeria’s manufacturing industries. There is no significant difference in

the mean responses of electrical and electronics technicians and of supervisors

concerning most of the items of the strategies for reducing or eliminating

maintenance errors in Nigeria’s manufacturing industries. Four items including

items 85-Distractions that are most likely to occur should be controlled, 98-Work

instruction should be written in clear simple, consistent language and with the

person who is going to use the instruction in mind, 100-Proactive processes for

accessing the risk of future maintenance should be put in place, and 105-Lessons

which may be learned-and remembered from incidents or equipment failures

should be pooled into computerized databases and be searched by key words as

part of risk assessment show that electrical/electronic technicians and supervisors

differ significantly in their opinions on the enabling strategies. Supervisors appear

to feel more strongly about the acceptability.

Errors are inevitable. Errors in maintenance which resulted into accidents and

equipment failures were caused by human characteristics, working environment,

management failures, fatigue, vigilance decrement, inadequate knowledge and

skills and violations of procedures. Errors in maintenance are committed by well

motivated, well experienced maintenance electrical and electronics technicians.

Most errors occur or are committed at times in services and in repairs in Nigeria’s

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manufacturing industries. Error reduction strategies to manage maintenance errors

are completely acceptable by the electrical and electronics technicians and

supervisors. In some instances supervisors and technicians differ significantly in

their agreed levels, because supervisors appear to feel more strongly about the

acceptability.

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CHAPTER V

SUMMARY, CONCLUSION AND RECOMMENDATIONS

This chapter is used to describe the summary and conclusions together with

the recommendations which are based on the findings of the study. The

implications of the study resulting from non implementation of the

recommendations are clearly stated along side with the recommendations for

further study as conclusion of the study.

Restatement of the Problem

Managers consider their maintenance operations to be high standard; quality

performance and safety incidents frequently reveal causes for concern; many of

these failures are associated with human aspects of maintenance (Dhillon, 2002).

There are various reasons why maintenance error involving particularly electrical

electronics technicians occur during maintenance repair and service actions. Some

locations of factory equipment expose the electrical and electronics technicians to

heat, grease and noise on the factory floor; some have to work in cramp spaces

(Fulterton Jr. 1996). Some technicians perform varied tasks in the environment

with time pressure, minimal feedback and sometimes under difficult ambient

conditions (Dhillon & Liu, 2006). According to Dhillon et al (2006) these

situational characteristics in combination with generic human erring tendencies

result in varied forms of errors specifically maintenance

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errors. Even experienced, highly trained, well-motivated technicians can make

simple slips and omissions and as such errors can initiate major accidents as well

as result in personal injury to maintenance personnel (Health and Safety Executive

(HSE) 2003). Mason (2009) explained that maintenance errors can impact on

safety and performance in a number of ways. He stressed that poor repairs for

example can increase the amount of breakdowns which in turn can increase the

risk associated with equipment failures and personal accidents.

Equipment failures as a result of maintenance errors have been a worrisome

problem in recent times in Nigeria’s manufacturing industries. Anyanwu (1997)

observed that ‘frequent machine breakdowns’ is among the factors responsible for

poor performance of manufacturing share in Gross Domestic Product between

1992 and 1995. In a study on fatal injuries in Nigerian factories, Ezenwa (2001)

reported loss of lives and injuries. These accidents might not be unconnected to

maintenance errors. Maintenance errors committed by electrical and electronics

technicians have causes which render them to occur with the obvious safety risk

and economic consequences. There are chances that maintenance errors will occur

and these could lead to catastrophic accidents or equipment failures if not

identified and managed.

Summary of Procedures

Human error in maintenance is responsible for levels of accidents and

equipment failures in process industries worldwide. To find out known types of

maintenance errors which cause levels of accidents and equipment failures in

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Nigeria’s manufacturing industries, a study of maintenance errors committed by

electrical and electronics technicians was conducted. Six research questions were

framed; four hypotheses were formulated to provide the desired information on

maintenance errors and their consequences. A cross sectional survey design was

adopted to provide means to obtain desired information from the population of all

electrical and electronics technicians and their supervisors working in Nigeria’s

manufacturing industries. Being a very large population, a sample size of 422

electrical and electronics technicians and their supervisors was drawn from it using

cluster sampling techniques. Questionnaire to elicit information from electrical and

electronics technicians and their supervisors was used to collect data. The

questionnaire comprises five sections with 105 measuring items including the bio

data. The five sections of the questionnaire were structured based on the

breakdown of maintenance errors namely types, causes, oftenness of recurrences

of maintenance errors occur, and some corresponding error reduction strategies.

Section A focuses on causes of maintenance errors; Section B deals with how

often errors occur in repairs and services; Section C contains items to elicit

information on commonly caused levels of accidents by known types of

maintenance errors; Section D contains items to elicit information on commonly

caused levels of equipment failures by known types of maintenance errors; while

section E concentrates on strategies for reducing maintenance errors. The

questionnaire items of sections A, B and E were structured on a five point likert

scale while questionnaire items of sections C and D were structured on four point

response modes. Three experts validated the questionnaire instrument. Cronbach

206

reliability coefficient of 0.94 was found to confirm the extent to which the items

belong together. The instrument was trial tested using four manufacturing

industries in Benue and Gombe States.

A total number of 422 copies of questionnaire forms were administered in

nine out of the twelve states on the respective technicians and supervisors. 375

completed copies of the questionnaire forms representing 88.86% were collected.

Data collected were analyzed, using mean, frequency, and t-test for comparison of

two means (for technicians and supervisors).

Summary of Major Findings

A summary of the major findings of the study include:

1, Working environment, management failures, fatigue, human characteristics,

violation of procedures and rules, inadequate knowledge and skills were

responsible for maintenance errors; while vigilance decrement appears not

to be the cause of maintenance errors in Nigeria’s manufacturing industries.

2 Apart from the error of forgetting and extending actions beyond the

procedures all other maintenance errors occur at times in repair and

servicing processes in Nigeria’s manufacturing industries

3 Maintenance error of forgetting and extending actions beyond the

procedures

rarely occurs during repair and servicing processes in Nigeria’s

manufacturing industries

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4 Serious accidents are caused by the recognition failures, memory failures,

rule-based mistakes, knowledge-based errors and violation errors

5 Serious equipment breakdowns or failures are caused by the recognition

failures,

6 memory failures, skill-based slips, rule-based mistakes, knowledge-based

errors and violation errors

7 Electrical and electronics technicians and supervisors do not differ

significantly in their experiences on how often errors occur during repair

processes except items 64, 71 and 78 of table 8

8 Electrical and electronics technicians and supervisors do not differ

significantly in their experiences in twenty-one of the twenty-five items on

how often errors occur during servicing processes in Nigeria’s

manufacturing industries.

9 Electrical and electronics technicians and supervisors differ significantly in

their experiences in four items namely 47, 51, 58 and 69 on how often

errors occur during servicing processes in Nigeria’s manufacturing

industries

10 Respondents were generally satisfied with the strategies for reducing or

eliminating maintenance errors in Nigeria’s manufacturing industries

11 Apart from items 84, 98, 100, and 105, which supervisors appear to feel

more strongly about the acceptability than the technicians, the opinions of

technicians and supervisors do not differ significantly on strategies for

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reducing or eliminating maintenance errors in Nigeria’s manufacturing

industries.

Implications of the Study

The findings of this study have implications for maintenance personnel,

manufacturers and institutions of learning. If the effects of maintenance errors

namely accidents and equipment failures must be understood by those concerned,

maintenance errors must be studied in institutions and manufacturing industries so

that manufacturers, management and maintenance personnel understand the effects

of maintenance errors and be able to control the risk they pose.

An implication of this study is the challenge that the finding pose to

industrial psychologists. Certain human characteristics which cause errors such as

distractions, forgetfulness (and preoccupations) which cannot be eliminated will

undoubtedly require counselling of maintenance personnel to recognize their

limitations. However, other identified multiple contributing factors will provide

the organization with specific focus to prevent future event.

Another implication of the findings of this study is that certain human

characteristics such as distractions, forgetfulness (and preoccupations) which cause

errors and cannot be eliminated make errors inevitable. Manufacturers or

organizations must realize that errors in maintenance can only be managed.

Further implication of the study is that errors occur at times, explicitly at

random; and therefore they are unpredictable. Manufacturers or organizations must

realize that every maintenance error has history and chain of events that led to

209

eventual outcome, and therefore intensify workforce awareness of maintenance

errors to ensure that maintenance errors are understood.

If the findings of the study are to be meaningful institutions of learning

have to partnership with industries, to introduce maintenance error reduction

strategies or maintenance error management course to ensure competence in

maintenance field of endeavour relative to production.

Conclusion

The study identified maintenance errors to be responsible for the levels of

accidents and equipment failures which can be controlled and prevented using the

strategies provided. The study has contributed to knowledge of maintenance errors

committed in Nigeria’s manufacturing industries in a number of ways.

1, The findings of the study ascertained that maintenance errors are caused by

multiple contributing factors including distractions and forgetfulness which

are difficult to eliminate. This makes maintenance errors inevitable.

2, The findings of the study ascertained that maintenance errors occur at times

in services and repairs in Nigeria’s manufacturing industries. In this way

they occur randomly.

3, The findings of the study established that serious accidents and serious

equipment failures were most commonly caused by recognition failures.

Accidents and equipment breakdowns however are functions of

maintenance errors. They also occur at random.

210

4, Finally, the study established that strategies for reducing or eliminating

maintenance errors are useful in Nigeria’s manufacturing industries.

Conclusively it is expected that sincere and objective implementation of the

identified strategies for reducing or eliminating maintenance errors in relevant

educational institutions and manufacturing industries will boost the economic

stability and reduce health hazards associated with maintenance errors.

Recommendations

The following recommendations are based on the findings of this study:

1. The effects of maintenance errors should be studied to enable maintenance

personnel to understand the risk maintenance pose.

2. Maintenance errors should be investigated to determine the root cause in

order to avoid a repeat

3. Good quality feedback should be provided to allow users to judge how

effective their actions have been and the state of equipment or individual as a

result of such actions

4. Management should ensure the maintenance personnel are trained or

retrained. Training can promote awareness and affect attitude. It reduces cost

associated with human performance

5. Management should ensure that a well design roster which minimizes fatigue

is in place

6. Management should undertake impact-assessment of maintenance errors.

211

7. Maintenance error is a form of human error therefore it is inevitable but it

should be managed

8. Each manufacturing industry should have an industrial psychology unit to

provide counselling services to maintenance personnel to enable them

recognise their limitations and realize their potentials

9. Institutions of learning should review technology programmes to include

human factors training to impart knowledge to learners to understand

important principles and procedures of maintenance errors and to integrate

them into the work environment.

Limitations of the Study

This research was subject to the limitations of data collection. It was found

some personnel managers did not return the questionnaire. Some managers after

receiving the questionnaires refused to complete them due to administrative and

security restrictions. In some instances some shift turnover affected the collection

of questionnaire.

There were also issues of leave, shift duties and change of jobs which serious

undermined the collection of questionnaire. Boko Haram and Jos intermittent

crises put obstacles to coverage of area of study which eventually resulted into non

collection of data in some parts of North Central zone and the whole of North East

geopolitical zone.

212

Suggestions for Further Study

The following areas were suggested for further study.

1 An investigation into relationship between maintenance errors and process

errors

2 Impact assessment of safety violations on maintenance quality in

manufacturing industries

3 Cause analysis and prevention against maintenance error occurrences in

industries.

4 Assessment of effects of human error on manufacturing industry

maintenance

5 Perceived role of individual and organizational factors in maintenance

performance

213

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Appendix A

LETTER TO MANAGEMENT

Department of Vocational Teacher Edu.,

University of Nigeria,

Nsukka

20-10-2008

Dear Sir/Madam

...................................

...................................

...................................

Request for Completion of Questionnaire

I am a student of University of Nigeria, Nsukka undertaking post graduate

doctoral programme in Industrial Technical Education. The attached is a

questionnaire required for the needed data from electrical and electronics

technicians and supervisors of your organization.

I therefore which your cooperation and hope you will allow electrical and

electronics technicians and their supervisors to complete the questionnaire as

indicated ininstructions to enable me answer the research questions raised in the

study. The information provided will be treated confidentially and will only be

used for the purpose of the study.

Thank you

Nande, Boniface Kwaghkar

225

Appendix B

ANALYSIS OF MAINTENANCE ERRORS COMMITTED BY ELECTRICAL

AND ELECTRONICS TECHNICIANS IN NIGERIA’S

MANUFACTURING INDUSTRIES

Questionnaire

This questionnaire is designed to analyze maintenance errors committed by electrical and

electronics technicians in Nigeria’s manufacturing industries. You are hereby requested to

respond to all items independently and honestly. The information you provide will be

used strictly for academic purpose

Personal Data: Tick right (√) the options that apply to you

1 Position

I Electrical and electronics technician [ ]

ii Sectional engineer or supervisor [ ]

2 Sex: Male [ ] Female [ ]

3 Ownership of industry

i Public (Government) [ ]

ii Private [ ]

SECTION A: Causes of maintenance errors

Tick right(√) one option which suits your observations or

experiences

Key:

SA Strongly agree A Agree

UN Undecided D Disagree

SD Strongly disagree

S/No. Causes of types of errors SA A UN D SD

Human characteristics

4 Attention paid to a number of tasks at the same time or at

once

5 Mind wandered off while performing a routine

component change

6 Past experiences nullified the common sense required to

make component change

7 Items to be remembered were forgotten

8 Difficulties in interpreting signals

9 Necessary tasks were overlooked in routine service or

repair process

10 Overconfidence in the information which confirmed the

initial and often incorrect diagnosis of a problem

226

S/No. Causes of types of errors SA A UN D SD

11 Persistent frustrating situations interfered with judgment

required while performing a task

Working environment

12 Distractions from immediate environment

13 High environmental temperature (heat) suppressed

creativity

14 Darkness affected viewing ability required for efficient

performance

15 Noise from immediate environment upset attentiveness

16 Glare affected viewing ability required for efficient

performance

17

Dust and gas polluted the environment and caused

discomfort which affected performance

Management Failures

18 Lack of clear work responsibility in order to get job done

or achieve targets

19 Excessive provision of incentives and bonuses for

meeting targets or achieving personal goals

20 Work written instructions without appropriate pictures

and graphics provided for the job

21 Work written instructions without appropriate

conspicuous reminder in order that critical steps are not

omitted were provided for work

22 Deficient uses of safety analyses

23 Unnecessary burden on employee due to overtime

24 Inadequate implementation of the corrective action plan

for identified problem

Vigilance decrement

25 Sensitivity decreased with extended searching time when

defects being searched for were relatively rare to be seen

26 Vigilance decreased with time as the number of hits was

few and far between or as faults did not occur after long

intervals of time

Fatigue

27 Excessive work shift hours broken by few hours of sleeps

28 Effects of alcohol taken (previously) on actions

29 Effects of drugs meant to be alert or active on act

227

S/No. Causes of types of errors SA A UN D SD

30 Influence of social problem (eg family, money) on

initiatives

31 Effects of anxiety on actions and intellectual initiatives

32 Stress due to competitive drive to be ahead of others

34 Working hard setting impossible deadlines to finish

physical activity while sleeping very little

Violations of procedures and rules

35 Opportunities presented themselves for short-cut or to do

things better

36 Over demonstration of unnecessary skills to win praise

37 Solving problems as they arise with inadequate planning

and advance preparation

38 Avoiding what seems to be unnecessary laborious

procedure

39 Avoiding what seems to be unnecessary effort to get job

done quickly

40 Expectations that rules have to be bent to get the work

done

41 Well-intended attempts to complete a task in the face of

time pressures or other challenges

Inadequate knowledge and skill

42 Deficient prior knowledge or experience of equipment

operations

43 Deficient rehearsal of activities

44 Deficient acquaintance with the job or equipment

operations

45 Skills used too often or habitual actions required less

attention

46 Deficient communications and practice for conducting

simultaneous operations in team work

228

Section B: How often errors occur in repairs and services

Tick right (√) one option, each from repairs and services which

corresponds to your own experiences

Key

Alw Always Mot Most of the time Stm Sometimes

Sel Seldom Nev Never

S/No Errors How often error recur

in repairs?

How often error recur

in services?

Alw Mot Stm Sel Nev Alw Mot Stm Sel Nev

47 Misidentification of objects,

signals and messages at material

time

48 State of problem not detected

and equipment started

49 Terminating a job before all

actions are complete

50 Following a specific procedure

and deviating to one more

familiar when the intention was

not to follow the familiar

procedure as was done

51 Leaving screws or bolts at

‘fingertight’ rather than

properly secured

52 Misapplying a good rule where

appropriate

53

Applying a bad rule to get job

done in certain situations

54 Removing parts of equipment

incorrectly

55

Making an untested

assumptions for example,

failing to check system before

acting

56 Forgetting and extending

actions beyond the procedure

57 Driving a screw excessively

which cause wear or damage

58

Forgetting to tag and/or lock-out unsafe equipment.

229

S/No Errors How often error recur

in repairs?

How often error recur

in services?

Alw Mot Stm Sel Nev Alw Mot Stm Sel Nev

59 Wounding cable insulations

60 Failing to inspect completed

tasks physically

61 Accepting an unacceptable

condition of equipment

62 Replacing parts of equipment

incorrectly

63 Not inspecting during repairs

affected components associated

with damaged one

64 Not clearing foreign objects

which cause short circuit when

the job is completed and

equipment energized.

65

Not communicating to others

when team work is completed

and equipment energized

66 Omitting what should be done

67 Taking unlikely and inaccurate

decisions

68 Information, signals and

message misinterpreted

69 Taking inaccurate measurement

or reading

70 Forgetting to replace worn and

frayed belts on equipment

71 Over-oiling motor bearings,

resulting in oil being thrown

onto insulation (fire hazard) and

onto the floor (fall hazard)

230

SECTION C: Types of Maintenance errors which cause accidents

(Types of Maintenance errors listed in the table when

committed give rise to accidents. Tick right (√) one option of

the accidents which corresponds to your experiences or

observations)

Key

Vsa Very serious/fatal accident Sa Serious accident

Ma Minor accident Na Negligible accident

S/No Type of maintenance errors Vsa/

Fa

Sa Ma Na

72 Recognition failures: e.g Misidentification of objects,

signals and messages/Non detection of problem states at the

right time cause

73 Memory failures: e.g Failing to remember items or

inability to recall or retrieve items from memory at material

time or omitting certain steps of sequence following

interruptions in sequence of actions or terminating the job

before all actions are complete lead to

74 Rule based mistakes: e.g, Misapplying a good

rule/Applying a bad rule to get the job done cause

75 Knowledge based errors: Performing an unusual task for

the first time cause

76 Skill-based slips: e.g, Branching errors – following specific

procedure but ending up with very familiar

procedure/Overshoot errors – following procedure,

forgetting to conclude and making additional steps to

complete the tasks cause

77 Violation errors: e.g, Not understanding how to apply

procedures/Acting as not being aware of procedure/Feeling

that procedures are irrelevant/Impossible to get job done if

procedures are followed strictly/Not adhering to rules to get

job done faster in order to have thrill/Failing to follow good

practice when solving problem(s) for the first time cause

231

Section D: Types of Maintenance errors which cause equipment failures

(Types of Maintenance errors listed in the table when committed give

rise equipment failures. Tick right (√) one option of the equipment

failures which corresponds to your experiences or observations)

Key:

Vsb Very serious breakdown Sb Serious breakdown

Mb Minor breakdown Nb Negligible

breakdown

S/No Type of maintenance errors Vsb Sb Mb Nb

78

Recognition failures: e.g Misidentification of objects,

signals and messages/Non detection of problem states at the

right time cause

79 Memory failures: e.g Failing to remember items or

inability to recall or retrieve items from memory at material

time or omitting certain steps of sequence following

interruptions in sequence of actions or terminating the job

before all actions are complete lead to

80 Rule based mistakes: e.g, Misapplying a good

rule/Applying a bad rule to get the job done cause

81 Knowledge based errors: e.g, Performing an unusual task

for the first time cause

82 Skill-based slips: e.g, Branching errors – following

specific procedure but ending up with very familiar

procedure/Overshoot errors – following procedure,

forgetting to conclude and making additional steps to

complete the tasks cause

83 Violation errors: e.g, Not understanding how to apply

procedures/Acting as not being aware of procedure/Feeling

that procedures are irrelevant/Impossible to get job done if

procedures are followed strictly/Not adhering to rules to get

job done faster in order to have thrill/Failing to follow good

practice when solving problem(s) for the first time cause

232

Section E: Strategies for reducing maintenance errors:

Tick right (√) one option which matches your opinion

S/No Strategies for reducing maintenance errors SA A UN D SD

84 Training in error-provoking factors should be provided to

maintenance personnel in order to give them an understanding and

awareness of factors and situations that may lead them to be more

error provoking

85 Distractions that are most likely to occur should be controlled

86 Mental rehearsal of tasks before they are performed should be

encouraged

87 Measures such as punishment or rehearsal of corrected tasks

to reduce the number of deliberate violations should be implemented

88 Place-markers should be inserted at appropriate points in the

procedure to avoid place-losing errors

89 Teamwork training should be provided to prevent accidents which

may likely occur as a result of poorly functioning teams

90

Personnel only should perform task when they are properly trained,

skilled and qualified

91 Well designed shift roster should be in place to minimize the impact

of fatigue

92 Adequate control should be put in place for managing over time work

93 Good housekeeping standards should be ensured as housekeeping

practices are good indicator of attitudes and culture relating to

quality.

94 Effective maintenance work instructions should be written and use

95 Appropriate use of picture and graphics should be made in work

instructions

96 Appropriate conspicuous reminders in order to ensure that critical

steps are not omitted should be incorporated in works instructions

97 Adequate independent inspections at key points should be

incorporated in the work instruction

98 Work instruction should be written in clear simple, consistent

language and with the person who is going to use the instruction in

mind

99 Tasks should be assigned appropriately: (infrequently and frequently

performed task tend to be those at greatest risk of human error due to

inexperienced of person performing the task and skilled based slips

and lapses of the person performing the tasks as he operates on ‘auto-

pilot’)

233

S/No Strategies for reducing maintenance errors SA A UN D SD

100 Proactive processes for accessing the risk of future maintenance

should be put in place (assessment areas include: the knowledge,

skills and experience; employee morale, availability of tools,

equipment and spare parts, workforce fatigue, stress time pressure,

shift rosters, adequacy of maintenance procedures and work

instructions)

101 Complex instructions should be grouped into phases, with each phase

consisting of many related tasks

102 Good quality feedback should be provided to allow users to judge

how effective their actions have been and what new state the system

is in as a result of those actions

103 Key risks that may prevent the job from being performed safely and

to the required quality standard should be focused on in the work

instructions

104 Hand-held computer with an interactive maintenance checklist which

specifically required the technician to acknowledge that certain stages

on the job had been completed should be employed for work

105 Lessons which may be learned-and remembered from incidents or

equipment failures should be pooled into computerized databases and

be searched by key words as part of risk assessment

234

Appendix C

Population of electrical and electronics technicians, supervisors in each State

State Types of manufacturing industries No of of

Techn

No of

supv

Sokoto, Kebbi, Kano, Katsina, Zamfara, Jigawa

Cement and food and drink fertilizer, food and drink, ceramics, metal processing, textiles, and vehicle assembly steel textiles,and food and drink

37 - 60 12 20 -

10 - 15 5 10 -

Borno, Yobe, Adamawa Taraba, Gombe Bauchi

food and drink, food and drink,(Numan and Yola) Cement, food and drink metal processing and vehicle assembly

15 - 27 - 20 15

4 - 9 - 12 8

Benue, Niger, Kwara, Kogi, Kaduna, Plateau, Nasarawa

Cement, food and drink pulp and paper, electricity power generation food and drink, textiles, soap and detergent, plastics and steel and iron food and cement food and drink, metal processing, oil refinery, pharmaceuticals, petro-chemicals, textiles and vehicle assembly Ceramics, food and drink, chemicals, plastics, steel and metal processing and Plastic Food

29 25 34 16 36 27 8

14 12 13 6 25 15 4

Lagos, Oyo, Ondo, Osun, Ekitti Ogun

food and drink, pulp and paper, metal processing, cement, plastic, paint, chemical, engineering, textiles, vehicle assembly, electrical equipment and appliances, rubber and foam, soap and detergent, footwear, furniture and pharmaceuticals food and drink, electrical equipment and appliances, plastic, pharmaceuticals, pulp and paper, metal processing, metal processing, wood processing, glass, oil palm processing, rubber and foam, food and drink and ceramics machine tools and steel Glass, oil palm processing, food and drink, food and drink, pulp and paper, metal processing, rubber and foam, cement, plastic, textiles

48 20 15 25 40

34 17 9 15 30

235

State Types of manufacturing industries No of of

Techn

No of

supv

Delta, Edo, Rivers, Bayelsa, Akwa Ibom Cross River

food and drink, wood processing, fertilizer, footwear, oil refinery, petrochemicals, steel, glass and textiles, wood processing, oil palm processing, pharmaceuticals, rubber and foam textiles, oil refinery, fertilizer, glass, petrochemicals, plastics, engineering, chemical and metal processing, aluminum smelter, pulp and paper, food and drink, chemicals and ceramics oil palm processing and rubber and foam, cement, food, palm oil processing, rubber processing

32 22 35 12 18

27 18 22 10 11

Enugu, Imo, Abia, Anambra Ebonye

Textiles, food and drink, oil palm processing, vehicle assembly, pharmaceuticals, metal processing and petrochemicals, glass, engineering, textiles, ceramics, food and drink, soap and detergent and oil palm processing metal processing, plastics, food and drink ,rubber and foam, ceramics, pulp and paper, soap and detergent

25 20 32 35 34

15 16 18 25 23

Total 745 418

Grand total 1,163

236

Appendix D

Sample of technicians, supervisors and sectional engineers

State Industries Population sample

Techn. Supv.

Kano Katsina

fertilizer, food and drink, ceramics, metal processing, textiles and vehicle assembly Steel

34 10

26 06

Kaduna Plateau

food and drink, fertilizer, ceramics, metal processing, textiles and vehicle assembly Ceramics, food and drink, chemicals, plastics, steel and metal processing,

56 -

47 -

Enugu Anambra

Textiles, food and drink, oil palm processing, vehicle assembly, metal processing, plastics, food and drink, rubber and foam, ceramics, pulp and paper, soap and detergent

26 40

16 32

Lagos Oyo

food and drink, pulp and paper, metal processing, cement, plastic, paint, chemical, engineering, textiles, vehicle assembly, electrical equipment and appliances, rubber and foam, soap and detergent, footwear, furniture and pharmaceuticals food and drink, electrical equipment and appliances, plastic, pharmaceuticals, pulp and paper, metal processing,.

27 15

21 10

Akwa Ibom Cross River

textiles, oil refinery, fertilizer, glass, petrochemicals plastics, engineering, chemical and metal processing, oil palm processing and rubber and foam

14 18

10 14

Sub-total 240 182

Grand total 422

237

Appendix E

Confidence = 95.0% 3.841459 Confidence = 99.0% 6.634897

Population

Size

P

r

o

0.05 0.035 0.025 0.01 0.05 0.035 0.025 0.01 The re

10 10 10 10 10 10 10 10 10 and m

20 19 20 20 20 19 20 20 20

30 28 29 29 30 29 29 30 30 For ex

50 44 47 48 50 47 48 49 50 of 99%

75 63 69 72 74 67 71 73 75

100 80 89 94 99 87 93 96 99

150 108 126 137 148 122 135 142 149

200 132 160 177 196 154 174 186 198

250 152 190 215 244 182 211 229 246

300 169 217 251 291 207 246 270 295

400 196 265 318 384 250 309 348 391

500 217 306 377 475 285 365 421 485

600 234 340 432 565 315 416 490 579

700 248 370 481 653 341 462 554 672

800 260 396 526 739 363 503 615 763 †

900 269 419 568 823 382 541 672 854

1,000 278 440 606 906 399 575 727 943

1,200 291 474 674 1067 427 636 827 1119

1,500 306 515 759 1297 460 712 959 1376

2,000 322 563 869 1655 498 808 1141 1785

2,500 333 597 952 1984 524 879 1288 2173

3,500 346 641 1068 2565 558 977 1510 2890

5,000 357 678 1176 3288 586 1066 1734 3842

7,500 365 710 1275 4211 610 1147 1960 5165

10,000 370 727 1332 4899 622 1193 2098 6239

25,000 378 760 1448 6939 646 1285 2399 9972

50,000 381 772 1491 8056 655 1318 2520 12455

75,000 382 776 1506 8514 658 1330 2563 13583

100,000 383 778 1513 8762 659 1336 2585 14227

250,000 384 782 1527 9248 662 1347 2626 15555

500,000 384 783 1532 9423 663 1350 2640 16055

1,000,000 384 783 1534 9512 663 1352 2647 16317

2,500,000 384 784 1536 9567 663 1353 2651 16478

10,000,000 384 784 1536 9594 663 1354 2653 16560

100,000,000 384 784 1537 9603 663 1354 2654 16584

264,000,000 384 784 1537 9603 663 1354 2654 16586

† Copyright, The Research Advisors (2006). All rights reserved.

Degree of Accuracy/Margin of Error Degree of Accuracy/Margin of Error

Required Sample Size†

from: The Research Advisors

238

Appendix F

Department of Vocational Teacher Edu.,

University of Nigeria,

Nsukka

20-10-2008

Dear Sir/Madam

Request for Assistance to Validate Questionnaire

I am undertaking a research for a post graduate programme at the University of Nigeria,

Nsukka. The title of the research is “Maintenance Errors Committed by Electrical and

Electronics technicians in Nigeria’s Manufacturing Industries”. The attached is a

questionnaire designed to collect part of the data needed for analysis. You are pleased

requested to:

1 examine the language and clarity of the questionnaire items

2 assess the appropriateness of the questionnaire to collect the needed information

from electrical and electronics technicians and their supervisors and make

suggestions

3 assess the extent to which questionnaire items cover the subject matter and make

suggestions

Please write yes or no in the margin against each item to indicate your agreement or

disagreement with the appropriateness of the item. You are also requested to point out

mistakes in the grammar and framing of the language. Any other suggestions that will

enable the subject to respond intelligently will be accepted

Thank you

Nande, Boniface Kwaghkar.

239

Appendix G

Suggestions made by the validators and corrections effected in the final draft of the

questionnaire

S/No. Item Suggestions made Corrections effected

1` Section A insert the interpretations interpretations effected

5 -10 of types of errors as the final draft

2 Section B insert the interpretations interpretations effected

11 -16 of types of errors as the final draft

Section C

3 19 remove “in a process” “in a process” removed

4 23 replace “bias” with over- overconfidence used

confidence

5 38 replace “event” with to be event replaced with“to

seen be seen”

6 39 make simpler by adding “ as faults did not

as faults did not occur occur after a long

after a long interval of time” interval of time was

effected

7 49 Overly be replaced with “over” over was used

8 51 change avoidance to avoiding avoiding effected

9 52 change avoidance to avoiding avoiding used

Section D

10 make headings to repairs and corrections effectd

services clearer

11 63 make clear by adding when when intention was not

intention was not to follow to follow the familiar

the familiar procedure as procedure as was done

was done effected

12 64 replace the whole item the item was replaced

with leaving screws or

240

S/No. Item Suggestions made Corrections effected

bolts at “finger tight”

rather than properly

secured

13 68 reframe as follows- the item was replaced

making an untested assum- as was suggested

ptions or failing to check

system before acting

Section E

14 88 “should” omitted be inserted corrections of“should”

made

15 give title to each section corrected

241

Appendix H

DISTRIBUTION AND RETURN OF COMPLETED QUESTIONNAIRE FORMS

FROM MANUFACTURING INDUSTRIES IN SAMPLE STATES

Manufacturing Industries No. of No.of

copies copies

issued ret’ned

ANAMBRA STATE

Onitsha 1 Zubee industries Co. nr. Toll gate, Nkpor Expressway 1 1 2 Geolies cable limited, Nkpor-Umuonji Road 3 3 3 Markson chemicals industries limited, Nkpor- Umuoji Rd. 2 2 4 Dueman chemicals industries limited, Nkpor- Umuoji Rd. 2 1 5 LIMCA (Nig. Mineral waters ind. Ltd.) Borromeo/Nkpor 7 5 6 Golden Oil industries limited, Atani road 4 4 7 Pokobros Group of industries (W/A) Ltd. Atani road 3 3 8 A N Ejeagwu and sons, Atani road 2 2 9 Brollo Industries Limited, Atani road 2 1 10 General Cotton Mills Ltd. Atani road/Bridge head 16 12

Nnewi 11 Jimex Ind. Ltd., Otolo 4 2 12 Ibeto Group of Industries limited, Umudim 5 3 13 Chicason Group of Industries Ltd., Umudim 8 8 14 Louis Carter Industries Limited 10 10 15 Nat. Engineering Design and Development Institute 2 2 Sub total 72 65

ENUGU STATE

Enugu Township 16 Nigerian Bottling Company Plc., 9th Mile 5 5 17 Seven – Up Bottling Company Plc., 9th Mile 6 6 18 Alo Aluminium Ltd., Emene Ind. Layout 5 2 19 ANAMMCO, Emene Ind. Layout 15 15 20 Emenite, Emene Ind. Layout 5 3 21 Juhel Pharmaceuticals, Emene Ind. Layout 6 6 22 Intecil Products Limited, Emene Ind. Layout 1 1 Sub total 42 38

CROSS RIVER STATE

Calabar 23 Niger Mills Company, Calabar 8 5 24 Dangote Flour Mills, Calabar 3 3 25 Calabar Free Trade Zone (CFTZ) 10 9

242

Manufacturing Industries No. of No.of

copies copies

issued ret’ned 26 System Metal, Calabar 2 1 27 Unicem Calabar 5 5 28 Real Oil Ltd., Odukpani 4 3

Sub total 32 26 AKWA IBOM STATE

Uyo 29 Plasto Crown Nig. Plc., 3 3 30 Otuku Nig. Ltd., 4 4 31 Peacock Paint Ind. Ekot-Etin, Etinan LGA 2 2 32 Aluminium Smelter Co. of Nig., (ALASCON) Ikot Obasi 15 13

Sub total 24 22

KATSINA STATE

Katsina

33 Steel rolling mill, Katsina 5 3 34 Saulawa Dana metal construction, Katsina 1 1 35 Katsina Neem Processing Co. Ltd., Katsina 1 1 36 Industrial Mineral Ltd., Katsina 9 7 Sub total 16 12

KADUNA STATE

Kaduna 37 IBBI limited, 1A Kudenda Industrial Estate 5 3 38 Sunglass Nig. Ltd., 4/8, Kudenda Industrial Estate 5 4 39 Kaduna Refinery and Petrochemical Company (KRPC) 30 27 40 Crittal – Hope, 2 Kachia Road 4 4 41 Mmab Cable, 10 Kachia Road 1 1 42 Turners Building products, Maichibi Rd. Kakuri Ind. Estate 5 5 43 Defence Industrial Corporation, Ahm Bello Way/Kakuri 21 21 44 7 – Up Bottling Company, Inuwa Abdulkadir Road 6 6 45 PAN limited, 114 Mallam Kulbi/ Inuwa Abdulkadir Road 6 4 46 RH Plastic, No. 2, Tanko Jafaru Close (behind DIC) 5 5 47 New Nigerian Newspapers 3 3 48 Dabo Motors, Constitution Road 2 1

Zaria 49 Rigid Park Containers Limited, No. 123 Dakace Ind. Layout 5 4 50 Zaria Industres Limited, Dakace Ind. Layout 5 5

103 93

243

Manufacturing Industries No. of No.of

copies copies

issued ret’ned

PLATEAU STATE Jos Security risk zone

OYO STATE

Ibadan

51 Zartech Nigeria Limited, Oluyole Industrial Estate 15 15 52 Wytak Limited, Oluyole Industrial Estate 5 5 53 Amir Plast Nig. Limited, Oluyole Industrial Estate 2 1 54 Black Horse Plastic Limited, Old Lagos Road 2 2 55 Assia Plastic Limited, Old Lagos Road 1 1 Sub total 25 24

KANO STATE

Kano

56 Royal Foam, Sharada Phase II 2 2 57 African Energy 6-A Nig. Ltd. 5 4 58 Mu’azu Inland Transport Ltd., Phase II 2 2 60 Dala Foods Nig. Ltd., Sharada Phase II 5 4 61 Kenson Electrical (Engr.) Work, 2 2 62 Agad Nig. Ltd., Phase II, Sharada Industrial estate 2 2 63 Bagco Sacks and Motors, Phase II, Sharada 5 3 64 Mamuda Industry, Chalana 5 3 65 Cello Paric, Sharada, Phase III 2 2 66 Dansa Food Nig. Ltd., Sharada, 4 3 67 Dangote Flour Mills Nig. Ltd., Sharada 4 4 Fatatan Nigeria Limited, Chalana 3 3 69 United Gases Nigeria Limited Chalana 3 2 70 Bua Flour Mills, Bompai 5 5 71 Unifoam Nigeria Limited 5 3 72 Vitafoam Manufacturing 2 2 73 Viva Polybag Nigeria Limited 4 2 Sub total 60 48

LAGOS STATE

Lagos

74 Jawa Pharmaceutical, Abimbola Industrial Estate 3 2 75 Afrotech Industries, Abimbola Industrial Estate 2 2 76 Afrab Chemicals Limited, Abimbola Industrial Estate 3 3 77 Limca Bottling Company, Abimbola Industrial Estate 7 7 78 Celplas industries, Ajao 3 3 79 Nuplas industries, Ajao Estate 3 3 80 Milenium 6 6 81 Capetex Ikeja 1 1

244

Manufacturing Industries No. of No.of

copies copies

issued ret’ned 82 E and O Power and Equipment Leasing Ltd Ikeja 4 4 83 Ipwa Plc 2 2 84 Mouka Ltd Ikeja Lagos 6 6 85 Primlaks 4 4 86 Maltex Plc 4 4 Sub total 48 47

Grand total 422 375

245

APPENDIX I

RELIABILITY COEFFICIENTS OF THE INSTRUMENT - MODEL=ALPHA SCALE - ALL VARIABLES SECTION A Causes of Maintenance Errors VARIABLES=V4 V5 V6 V7 V8 V9 V10 V11 V12 V13 V14 V15 V16 V17 V18 V19 V20 V21 V22 V23 V24 V25 V26 V27 V28 V29 V30 V31 V32 V33 V34 V35 V36 V37 V38 V39 V40 V41 V42 V43 V44 V45 V46

Reliability Statistics

Cronbach's

Alpha N of Items

.900 43

Item-Total Statistics

Scale Mean if

Item Deleted

Scale

Variance if

Item Deleted

Corrected

Item-Total

Correlation

Cronbach's

Alpha if Item

Deleted

V4 158.3500 459.818 -.026 .903

V5 158.6000 418.147 .678 .893

V6 158.7500 439.355 .319 .899

V7 158.5500 443.313 .280 .899

V8 158.7500 433.461 .387 .898

V9 158.6000 453.200 .080 .903

V10 158.2500 427.355 .599 .894

V11 158.8500 427.503 .465 .896

V12 159.1500 444.345 .189 .902

V13 157.8500 436.450 .551 .896

V14 157.6000 442.147 .492 .897

V15 158.1000 436.832 .602 .895

V16 158.2500 428.303 .580 .895

V17 157.8500 448.239 .405 .898

V18 157.9000 456.200 .105 .900

V19 158.7000 443.168 .281 .899

V20 158.5500 438.576 .556 .896

V21 158.6500 431.503 .524 .896

V22 158.6500 433.292 .488 .896

246

V23 158.0500 432.261 .521 .896

V24 158.5000 426.789 .581 .895

V25 158.4500 436.261 .498 .896

V26 158.6500 440.345 .363 .898

V27 158.1500 445.082 .319 .898

V28 157.7000 435.063 .608 .895

V29 159.0000 439.158 .375 .898

V30 158.2000 429.642 .523 .895

V31 158.6000 448.989 .412 .898

V32 158.4000 429.200 .792 .893

V33 158.6000 437.516 .545 .896

V34 158.4000 421.937 .766 .892

V35 158.6500 444.871 .260 .899

V36 158.6500 445.503 .480 .897

V37 158.2000 440.589 .498 .896

V38 158.2000 462.379 -.079 .903

V39 158.0500 455.524 .084 .901

V40 158.6500 443.082 .307 .899

V41 158.6000 470.147 -.209 .907

V42 157.9500 427.839 .747 .893

V43 158.4500 434.261 .496 .896

V44 157.7500 438.197 .567 .896

V45 158.4500 457.418 .042 .901

V46 158.0500 429.418 .661 .894

SECTION B How Often Maintenance Errors Occur In Repairs (Re) VARIABLES=Re47 Re48 Re49 Re50 Re51 Re52 Re53 Re54 Re55 Re56 Re57 Re58 Re59 Re60 Re61 Re62 Re63 Re64 Re65 Re66 Re67 Re68 Re69 Re70 Re71

Reliability Statistics

Cronbach's

Alpha N of Items

.932 25

247

Item-Total Statistics

Scale Mean if

Item Deleted

Scale

Variance if

Item Deleted

Corrected

Item-Total

Correlation

Cronbach's

Alpha if Item

Deleted

Re47 55.4000 447.726 .734 .927

Re48 55.5500 480.261 .431 .931

Re49 56.1000 457.989 .592 .929

Re50 55.4500 440.892 .819 .925

Re51 56.2000 491.221 .065 .934

Re52 56.2000 428.379 .852 .924

Re53 56.4000 465.726 .432 .931

Re54 56.0500 437.839 .833 .925

Re55 56.2000 451.116 .602 .929

Re56 56.7000 481.063 .300 .932

Re57 56.2500 487.671 .105 .935

Re58 56.3500 489.292 .112 .934

Re59 56.4000 433.621 .832 .925

Re60 55.8500 463.608 .294 .936

Re61 56.5000 445.947 .710 .927

Re62 56.1000 434.516 .852 .924

Re63 56.1000 468.305 .476 .930

Re64 56.2500 435.145 .839 .925

Re65 56.5000 479.632 .286 .933

Re66 55.6000 443.621 .836 .925

Re67 56.3000 461.695 .548 .929

Re68 55.4000 433.937 .903 .924

Re69 55.5500 429.945 .921 .923

Re70 56.2500 459.355 .481 .931

Re71 55.9500 486.050 .128 .935

In Servicing (Sv) VARIABLES=Sv47 Sv48 Sv49 Sv50 Sv51 Sv52 Sv53 Sv54 Sv55 Sv56 Sv57 Sv58 Sv59 Sv60 Sv61 Sv62 Sv63 Sv64 Sv65 Sv66 Sv67 Sv68 Sv69 Sv70 Sv71

Reliability Statistics

248

Cronbach's

Alpha N of Items

.933 25

Item-Total Statistics

Scale Mean if

Item Deleted

Scale

Variance if

Item Deleted

Corrected

Item-Total

Correlation

Cronbach's

Alpha if Item

Deleted

Sv47 52.2000 463.221 .443 .932

Sv48 52.3000 467.274 .514 .931

Sv49 52.4000 456.147 .541 .931

Sv50 52.4500 434.261 .856 .926

Sv51 52.9000 489.147 .104 .935

Sv52 52.5500 436.471 .718 .928

Sv53 53.0000 458.526 .549 .931

Sv54 52.8500 434.661 .858 .926

Sv55 52.5500 448.892 .631 .930

Sv56 53.1500 486.239 .185 .935

Sv57 52.7500 484.934 .151 .936

Sv58 52.6000 481.200 .249 .934

Sv59 52.9000 446.937 .688 .929

Sv60 52.5500 456.682 .478 .932

Sv61 52.8500 446.029 .694 .929

Sv62 52.4000 430.779 .873 .925

Sv63 52.8000 462.379 .616 .930

Sv64 52.5500 434.997 .850 .926

Sv65 53.0000 474.842 .399 .933

Sv66 52.7500 458.092 .531 .931

Sv67 52.8000 446.168 .757 .928

Sv68 52.2500 422.197 .917 .924

Sv69 52.3500 432.239 .832 .926

Sv70 52.8000 464.063 .453 .932

Sv71 52.7000 497.800 -.116 .937

249

SECTION C Leveis of accidents Reliability - /VARIABLES=V72 V73 V74 V75 V76 V77

/SCALE('ALL VARIABLES') ALL /MODEL=ALPHA /STATISTICS=DESCRIPTIVE

Reliability Statistics

Cronbach's

Alpha N of Items

.429 6

Item Statistics

Mean Std. Deviation N

Recognition failures 2.6413 1.06294 368

Memory failures 2.5027 1.08494 368

Skill-based slips 2.3832 1.02153 368

Rule-based mistakes 2.7364 .93877 368

Knowledge-based errors 2.7446 .99589 368

Violation errors 2.8940 1.00525 368

SECTION D Levels of equipment breakdown

Reliability - /VARIABLES=V78 V79 V80 V81 V82 V83 /SCALE('ALL VARIABLES') ALL /MODEL=ALPHA /STATISTICS=DESCRIPTIVE.

Reliability Statistics

Cronbach's

Alpha N of Items

.590 6

Item Statistics

Mean Std. Deviation N

Recognition failures 2.8482 .96332 369

Memory failures 2.8022 .93912 369

Skill-based slips 2.5799 .91469 369

Rule-based mistakes 2.5718 1.01396 369

Knowledge-based err 2.7127 1.07029 369

Violation errors 2.7507 1.06202 369

250

SECTION E Strategies for Reducing or Eliminating Maintenance Errors VARIABLES=V84 V85 V86 V87 V88 V89 V90 V91 V92 V93 V94 V95 V96 V97 V98 V99 V100 V101 V102 V103 V104 V105

Reliability Statistics

Cronbach's

Alpha N of Items

.903 22

Item-Total Statistics

Scale Mean if

Item Deleted

Scale

Variance if

Item Deleted

Corrected

Item-Total

Correlation

Cronbach's

Alpha if Item

Deleted

V84 91.5500 121.734 .050 .919

V85 90.9500 121.839 .220 .904

V86 91.3500 121.924 .134 .908

V87 91.1500 113.397 .625 .896

V88 90.8000 116.905 .545 .899

V89 90.7000 116.011 .607 .897

V90 90.8000 111.326 .664 .895

V91 90.8000 114.589 .411 .902

V92 90.6000 121.516 .343 .902

V93 90.4500 120.261 .559 .900

V94 90.9000 116.937 .353 .903

V95 90.8000 109.853 .743 .893

V96 90.9000 107.779 .867 .890

V97 90.9000 109.568 .769 .892

V98 90.5000 119.632 .579 .900

V99 91.1000 107.884 .809 .891

V100 90.7000 120.642 .406 .901

V101 91.6500 101.713 .831 .889

V102 90.9500 115.313 .469 .900

V103 90.8000 120.695 .402 .901

V104 91.0500 106.050 .889 .888

V105 90.8500 110.976 .686 .894

251

OVERALL RELIABILTY COEFFICIENT VARIABLES=V4 V5 V6 V7 V8 V9 V10 V11 V12 V13 V14 V15 V16 V17 V18 V19 V20 V21 V22 V23 V24 V25 V26 V27 V28 V29 V30 V31 V32 V33 V34 V35 V36 V37 V38 V39 V40 V41 V42 V43 V44 V45 V46 Re47 Re48 Re49 Re50 Re53 Re51 Re52 Re54 Re55 Re56 Re57 Re58 Re59 Re60 Re61 Re62 Re63 Re64 Re65 Re66 Re67 Re68 Re69 Re70 Re71 Sv47 Sv48 Sv49 Sv50 Sv51 Sv52 Sv53 Sv54 Sv55 Sv56 Sv57 Sv58 Sv59 Sv60 Sv61 Sv62 Sv63 Sv64 Sv65 Sv66 Sv67 Sv68 Sv69 Sv70 Sv71 V84 V85 V86 V87 V88 V89 V90 V91 V92 V93 V94 V95 V96 V97 V98 V99 V100 V101 V102 V103 V104 V105

Reliability Statistics

Cronbach's

Alpha N of Items

.959 115

Item-Total Statistics

Scale Mean if

Item Deleted

Scale

Variance if

Item Deleted

Corrected

Item-Total

Correlation

Cronbach's

Alpha if Item

Deleted

V4 366.4500 3543.629 .283 .959

V5 366.7000 3505.063 .462 .958

V6 366.8500 3521.187 .377 .959

V7 366.6500 3591.187 -.049 .959

V8 366.8500 3565.397 .099 .959

V9 366.7000 3593.274 -.059 .960

V10 366.3500 3522.134 .415 .958

V11 366.9500 3557.418 .137 .959

V12 367.2500 3483.461 .518 .958

V13 365.9500 3529.313 .474 .958

V14 365.7000 3558.432 .266 .959

V15 366.2000 3544.484 .380 .959

V16 366.3500 3508.661 .506 .958

V17 365.9500 3598.787 -.176 .959

V18 366.0000 3553.368 .369 .959

V19 366.8000 3558.063 .169 .959

V20 366.6500 3524.976 .569 .958

V21 366.7500 3519.145 .441 .958

252

V22 366.7500 3533.461 .343 .959

V23 366.1500 3513.713 .489 .958

V24 366.6000 3550.568 .212 .959

V25 366.5500 3553.945 .235 .959

V26 366.7500 3569.145 .104 .959

V27 366.2500 3556.513 .227 .959

V28 365.8000 3544.063 .359 .959

V29 367.1000 3538.200 .313 .959

V30 366.3000 3549.274 .219 .959

V31 366.7000 3564.853 .279 .959

V32 366.5000 3496.053 .822 .958

V33 366.7000 3550.958 .298 .959

V34 366.5000 3488.053 .698 .958

V35 366.7500 3528.197 .379 .959

V36 366.7500 3565.776 .232 .959

V37 366.3000 3531.063 .508 .958

V38 366.3000 3578.958 .042 .959

V39 366.1500 3568.871 .134 .959

V40 366.7500 3547.355 .258 .959

V41 366.7000 3565.274 .117 .959

V42 366.0500 3524.997 .497 .958

V43 366.5500 3540.576 .311 .959

V44 365.8500 3539.503 .429 .958

V45 366.5500 3580.682 .035 .959

V46 366.1500 3528.239 .440 .958

Re47 367.2500 3495.145 .514 .958

Re48 367.4000 3548.358 .410 .959

Re49 367.9500 3486.050 .598 .958

Re50 367.3000 3454.116 .730 .958

Re53 368.2500 3508.513 .435 .958

Re51 368.0500 3566.366 .159 .959

Re52 368.0500 3412.471 .809 .957

Re54 367.9000 3451.463 .715 .958

Re55 368.0500 3490.050 .488 .958

Re56 368.5500 3552.050 .277 .959

253

Re57 368.1000 3569.674 .097 .959

Re58 368.2000 3574.168 .091 .959

Re59 368.2500 3424.303 .802 .957

Re60 367.7000 3512.537 .273 .959

Re61 368.3500 3463.292 .655 .958

Re62 367.9500 3429.945 .802 .957

Re63 367.9500 3531.418 .362 .959

Re64 368.1000 3435.463 .770 .957

Re65 368.3500 3553.503 .229 .959

Re66 367.4500 3478.997 .632 .958

Re67 368.1500 3494.134 .567 .958

Re68 367.2500 3446.829 .745 .958

Re69 367.4000 3423.095 .836 .957

Re70 368.1000 3491.989 .481 .958

Re71 367.8000 3553.221 .200 .959

Sv47 367.6000 3529.516 .301 .959

Sv48 367.7000 3525.589 .430 .958

Sv49 367.8000 3481.958 .557 .958

Sv50 367.8500 3428.871 .820 .957

Sv51 368.3000 3565.695 .178 .959

Sv52 367.9500 3415.839 .786 .957

Sv53 368.4000 3496.779 .514 .958

Sv54 368.2500 3428.303 .830 .957

Sv55 367.9500 3487.734 .505 .958

Sv56 368.5500 3561.313 .226 .959

Sv57 368.1500 3586.029 -.015 .959

Sv58 368.0000 3566.421 .139 .959

Sv59 368.3000 3449.589 .738 .958

Sv60 367.9500 3491.208 .457 .958

Sv61 368.2500 3457.671 .685 .958

Sv62 367.8000 3436.905 .744 .958

Sv63 368.2000 3520.589 .467 .958

Sv64 367.9500 3437.524 .778 .957

Sv65 368.4000 3545.305 .315 .959

Sv66 368.1500 3484.029 .566 .958

254

Sv67 368.2000 3439.853 .854 .957

Sv68 367.6500 3410.555 .808 .957

Sv69 367.7500 3443.039 .698 .958

Sv70 368.2000 3517.537 .387 .959

Sv71 368.1000 3595.884 -.108 .959

V84 366.5500 3540.366 .248 .959

V85 365.9500 3567.313 .224 .959

V86 366.3500 3632.029 -.432 .960

V87 366.1500 3516.871 .670 .958

V88 365.8000 3557.853 .330 .959

V89 365.7000 3572.958 .145 .959

V90 365.8000 3585.011 -.005 .959

V91 365.8000 3597.116 -.098 .959

V92 365.6000 3558.779 .451 .959

V93 365.4500 3563.629 .440 .959

V94 365.9000 3565.779 .158 .959

V95 365.8000 3530.800 .478 .958

V96 365.9000 3542.832 .375 .959

V97 365.9000 3526.832 .520 .958

V98 365.5000 3572.895 .231 .959

V99 366.1000 3545.568 .330 .959

V100 365.7000 3564.326 .341 .959

V101 366.6500 3558.450 .161 .959

V103 365.8000 3572.905 .200 .959

V104 366.0500 3535.208 .411 .958

V105 365.8500 3555.924 .255 .959

255

APPENDIX J

STATISTICS COMPUTATION OF COLLECTED DATA Research Question 1

DESCRIPTIVES VARIABLES=V4 V5 V6 V7 V8 V9 V10 V11 V12 V13 V14 V15 V16 V17 V18 V19 V20 V21 V22 V23 V24 V25 V26 V27 V28 V29 V30 V31 V32 V33 V34 V35 V36 V37 V38 V39 V40 V41 V42 V43 V44 V45 V46/ STATISTICS=MEAN STDDEV MIN MAX.

Descriptive Statistics

N Range Minimum Maximum Sum Mean

Std.

Deviation

V4 375 4.00 1.00 5.00 1487.00 3.9653 1.14992

V5 374 4.00 1.00 5.00 1418.00 3.7914 1.21401

V6 375 4.00 1.00 5.00 1246.00 3.3227 1.34637

V7 375 4.00 1.00 5.00 1363.00 3.6347 1.23772

V8 375 4.00 1.00 5.00 1465.00 3.9067 1.16285

V9 375 4.00 1.00 5.00 1370.00 3.6533 1.21150

V10 375 4.00 1.00 5.00 1385.00 3.6933 1.24717

V11 375 4.00 1.00 5.00 1382.00 3.6853 1.26963

V12 375 4.00 1.00 5.00 1406.00 3.7493 1.20431

V13 375 4.00 1.00 5.00 1286.00 3.4293 1.40651

V14 375 4.00 1.00 5.00 1461.00 3.8960 1.34139

V15 375 4.00 1.00 5.00 1361.00 3.6293 1.32588

V16 375 5.00 .00 5.00 1293.00 3.4480 1.30889

V17 375 4.00 1.00 5.00 1459.00 3.8907 1.28808

V18 375 4.00 1.00 5.00 1522.00 4.0587 1.13843

V19 375 5.00 .00 5.00 1023.00 2.7280 1.54457

V20 374 4.00 1.00 5.00 1231.00 3.2914 1.29676

V21 375 5.00 .00 5.00 1276.00 3.4027 1.28774

V22 375 5.00 .00 5.00 1446.00 3.8560 1.15419

V23 375 4.00 1.00 5.00 1338.00 3.5680 1.31427

V24 375 4.00 1.00 5.00 1384.00 3.6907 1.24544

V25 375 5.00 .00 5.00 1227.00 3.2720 1.26898

V26 375 5.00 .00 5.00 1160.00 3.0933 1.23207

V27 375 4.00 1.00 5.00 1478.00 3.9413 1.17540

V28 375 4.00 1.00 5.00 1454.00 3.8773 1.32475

256

V29 375 5.00 .00 5.00 1355.00 3.6133 1.27809

V30 375 4.00 1.00 5.00 1467.00 3.9120 1.17698

V31 375 5.00 .00 5.00 1369.00 3.6507 1.17145

V32 375 4.00 1.00 5.00 1314.00 3.5040 1.30173

V33 375 4.00 1.00 5.00 1334.00 3.5573 1.18651

V34 375 4.00 1.00 5.00 1473.00 3.9280 1.26560

V35 375 5.00 .00 5.00 1277.00 3.4053 1.27543

V36 375 5.00 .00 5.00 1359.00 3.6240 1.24744

V37 375 4.00 1.00 5.00 1297.00 3.4587 1.24220

V38 375 5.00 .00 5.00 1271.00 3.3893 1.29907

V39 375 5.00 .00 5.00 1248.00 3.3280 1.34110

V40 375 5.00 .00 5.00 1294.00 3.4507 1.36890

V41 375 5.00 .00 5.00 1321.00 3.5227 1.25766

V42 375 4.00 1.00 5.00 1570.00 4.1867 1.11256

V43 375 5.00 .00 5.00 1328.00 3.5413 1.22268

V44 375 5.00 .00 5.00 1439.00 3.8373 1.23786

V45 375 4.00 1.00 5.00 1247.00 3.3253 1.33676

V46 375 4.00 1.00 5.00 1474.00 3.9307 1.15416

Valid N

(listwise) 373

Research Question 2 DESCRIPTIVES VARIABLES=Re47 Re48 Re49 Re50 Re51 Re52 Re53 Re54 Re55 Re56 Re57 Re58 Re59 Re60 Re61 Re62 Re63 Re64 Re65 Re66 Re67 Re68 Re69 Re 70 Re71/ STATISTICS=MEAN STDDEV MIN MAX.

Descriptive Statistics

N Minimum Maximum Mean

Std.

Deviation

Re47 375 .00 5.00 3.1200 1.20116

Re48 375 .00 5.00 3.1173 1.09793

Re49 375 .00 5.00 2.6213 1.31855

Re50 375 .00 5.00 2.8827 1.16871

Re51 375 .00 5.00 2.7813 1.34450

257

Re52 375 .00 5.00 2.8453 1.44139

Re53 375 .00 5.00 2.7813 1.32244

Re54 375 .00 5.00 2.7493 1.30449

Re55 375 .00 5.00 2.7627 1.33232

Re56 375 .00 5.00 2.4933 1.25997

Re57 375 .00 5.00 2.8347 1.22119

Re58 375 .00 5.00 2.7680 1.08319

Re59 375 .00 5.00 2.7787 1.30878

Re60 375 .00 5.00 2.7120 1.31110

Re61 375 .00 5.00 2.6987 1.40182

Re62 375 .00 5.00 2.7600 1.47384

Re63 375 .00 5.00 2.7680 1.24404

Re64 375 1.00 5.00 2.7573 1.42450

Re65 375 1.00 5.00 2.6293 1.39084

Re66 375 .00 5.00 2.9067 1.41585

Re67 375 .00 5.00 2.7653 1.36549

Re68 375 .00 5.00 3.0080 1.35924

Re69 375 .00 5.00 2.8533 1.27390

Re70 375 .00 5.00 2.7653 1.42865

Re71 375 .00 5.00 2.8027 1.33384

Valid N

(listwise) 375

Research Question 3 DESCRIPTIVES VARIABLES=Sv47 Sv48 Sv49 Sv50 Sv51 Sv52 Sv53 Sv54 Sv55 Sv56 Sv57 Sv58 Sv59 Sv60 Sv61 Sv62 Sv63 Sv64 Sv65 Sv66 Sv67 Sv68 Sv69 Sv70 Sv71/ STATISTICS=MEAN STDDEV MIN MAX.

Descriptive Statistics

N Minimum Maximum Mean

Std.

Deviation

Sv47 375 .00 5.00 2.8720 1.25372

Sv48 375 .00 5.00 2.8320 1.18188

Sv49 375 .00 5.00 2.5573 1.36859

Sv50 375 .00 5.00 2.7280 1.24344

Sv51 375 .00 5.00 2.6187 1.36071

Sv52 375 .00 5.00 2.6587 1.45366

258

Sv53 375 .00 5.00 2.6293 1.35579

Sv54 375 .00 5.00 2.6000 1.30199

Sv55 375 .00 5.00 2.6373 1.33312

Sv56 375 .00 5.00 2.4427 1.29015

Sv57 375 .00 5.00 2.5627 1.23266

Sv58 375 .00 5.00 2.6613 1.28337

Sv59 375 .00 5.00 2.5227 1.28083

Sv60 375 .00 5.00 2.5387 1.28877

Sv61 375 .00 5.00 2.5813 1.36149

Sv62 375 .00 5.00 2.6160 1.45586

Sv63 375 .00 5.00 2.6853 1.32527

Sv64 375 .00 5.00 2.6400 1.45006

Sv65 375 1.00 5.00 2.5840 1.33955

Sv66 375 .00 5.00 2.7040 1.34656

Sv67 375 .00 5.00 2.5893 1.29660

Sv68 375 .00 5.00 2.7787 1.35890

Sv69 375 .00 5.00 2.7147 1.30862

Sv70 375 .00 5.00 2.6480 1.39473

Sv71 375 .00 5.00 2.5973 1.34661

Valid N

(listwise) 375

Research Question 4 DESCRIPTIVES VARIABLES=V72 V73 V74 V75 V76 V77/ STATISTICS=MEAN STDDEV MIN MAX.

Descriptive Statistics

N Minimum Maximum Mean Std. Deviation

V72 Recognition failures 372 1.00 4.00 2.6398 1.06871

V73 Memory failures 371 1.00 4.00 2.5013 1.08148

V74 Skill-based slips 372 1.00 4.00 2.3817 1.02239

V75 Rule-based mistakes 373 1.00 4.00 2.7346 .94289

259

V76 Knowledge-based errors 372 1.00 4.00 2.7527 .99493

V77 Violation errors 373 1.00 4.00 2.8981 1.00286

Valid N (listwise) 368

Research Question 5 DESCRIPTIVES VARIABLES=V78 V79 V80 V81 V82 V83/ STATISTICS=MEAN STDDEV MIN MAX.

Descriptive Statistics

N Minimum Maximum Mean Std. Deviation

V78 Recognition failures 373 1.00 4.00 2.8499 .96385

V79 Memory failures 372 1.00 4.00 2.8011 .93836

V80 Skill-based slips 373 1.00 4.00 2.5764 .91445

V81 Rule-based mistakes 374 1.00 4.00 2.5802 1.01609

V82 Knowledge-based errors 372 1.00 4.00 2.7177 1.07076

V83 Violation errors 373 1.00 4.00 2.7453 1.06610

Valid N (listwise) 369

Research Question 6

DESCRIPTIVES VARIABLES=V84 V85 V86 V87 V88 V89 V90 V91 V92 V93 V94 V95 V96 V97 V98 V99 V100 V101 V102 V103 V104 V105 STATISTICS=MEAN STDDEV MIN MAX.

Descriptive Statistics

N Minimum Maximum Mean

Std.

Deviation

V84 375 .00 5.00 4.0960 1.20443

V85 375 1.00 5.00 4.3280 .71023

V86 375 1.00 5.00 4.0507 .99469

V87 375 1.00 5.00 3.7040 1.16791

V88 375 1.00 5.00 3.9920 .98515

V89 375 1.00 5.00 4.5013 .73446

V90 375 1.00 5.00 4.4133 .89999

V91 375 .00 5.00 4.3520 .86144

V92 375 1.00 5.00 4.2907 .76577

V93 375 .00 5.00 4.3893 .90032

260

V94 375 .00 5.00 4.3840 .81547

V95 375 1.00 5.00 4.2453 .92994

V96 375 1.00 5.00 4.2933 .78715

V97 375 1.00 5.00 3.9600 1.00320

V98 375 1.00 5.00 4.5120 .71219

V99 375 1.00 5.00 4.0400 1.01907

V100 375 1.00 5.00 4.3600 .86587

V101 375 1.00 5.00 3.8907 1.07290

V102 375 1.00 5.00 4.3413 .74272

V103 375 1.00 5.00 4.2480 .84641

V104 375 1.00 5.00 3.8960 1.09318

V105 375 1.00 5.00 4.3227 .76340

Valid N

(listwise) 375