ethics: case studies · • • kansas city hyatt regency walkway collapse, mo (1981) • • teton...

Ethics:Ethics: Case StudiesCase Studies

Using Case Studies in Using Case Studies in Engineering EthicsEngineering Ethics

Case 1Case 1

The Ford PintoThe Ford Pinto

The Ford Pinto CaseThe Ford Pinto Case

•• First introduced in 1970 and First introduced in 1970 and built through 1980 model year.built through 1980 model year.

•• During crash tests which During crash tests which proceeded sales of the Pinto to proceeded sales of the Pinto to the public, a serious design the public, a serious design flaw was discovered. flaw was discovered.

•• The gas tank was so designed The gas tank was so designed that when it was involved in a that when it was involved in a rear end collision at an impact rear end collision at an impact speed of 20 MPH or greater, speed of 20 MPH or greater, the tank was likely to rupture, the tank was likely to rupture, causing a fire and explosion.causing a fire and explosion.


•• The gas tank was The gas tank was only 5 inches forward only 5 inches forward of the rear sheet of the rear sheet metal of the body and metal of the body and only 3 inches from only 3 inches from the rear axle. the rear axle.

•• In most rearIn most rear--end end crashes, the axle crashes, the axle housing deformed the housing deformed the gas tank and sharp gas tank and sharp bolts punctured the bolts punctured the tank. tank.


•• Following crash tests, the Following crash tests, the conclusion was that the rear conclusion was that the rear end structure was not end structure was not satisfactory. satisfactory.

•• Suggested changes would Suggested changes would have cost about $11 per car. have cost about $11 per car.

•• A confidential company memo A confidential company memo directed that the safety directed that the safety features not be adopted until features not be adopted until required by law.required by law.


•• Ford Motor Ford Motor Company knew Company knew about the problems.about the problems.

•• Table at right is Table at right is taken from an taken from an internal Ford internal Ford memorandum dated memorandum dated 1111--1616--1973.1973.


Summary:Summary:•• Design was rushed. The normal time to produce an Design was rushed. The normal time to produce an

automobile is 43 months automobile is 43 months -- Ford took 25 for the Pinto. Ford took 25 for the Pinto. •• Before production, Ford engineers discovered flaws Before production, Ford engineers discovered flaws

in the carin the car’’s design. In nearly all rears design. In nearly all rear--end crash test end crash test collisions the Pinto's fuel system would rupture collisions the Pinto's fuel system would rupture extremely easily. extremely easily.

•• Because assemblyBecause assembly--line tooling was already in place line tooling was already in place when engineers found this defect, top Ford officials when engineers found this defect, top Ford officials decided to manufacture the car anyway, exploding decided to manufacture the car anyway, exploding gas tank and all, even though Ford owned the patent gas tank and all, even though Ford owned the patent on a much safer gas tank.on a much safer gas tank.


•• What are the ethical elements that we What are the ethical elements that we need to consider? Who are the players?need to consider? Who are the players?


•• Ethics Questions:Ethics Questions:–– What were the What were the

responsibilities of the Ford responsibilities of the Ford design engineers?design engineers?

–– What were the What were the responsibilities of the responsibilities of the crashcrash--test engineers?test engineers?

–– What were the What were the responsibilities of company responsibilities of company management management –– including including subcontractors? subcontractors?

Case 2Case 2

The DC 10 Cargo DoorThe DC 10 Cargo Door

DC 10 Cargo DoorDC 10 Cargo Door

•• On June 12, 1972 A DCOn June 12, 1972 A DC--10 left 10 left Detroit with 67 passengers.Detroit with 67 passengers.

•• After reaching 12,000 feet over After reaching 12,000 feet over Windsor, Ontario the cargo door Windsor, Ontario the cargo door blew off, collapsing the floor and blew off, collapsing the floor and disrupting all hydraulic controls to disrupting all hydraulic controls to tail section.tail section.

•• Only the pilotOnly the pilot’’s skill and the light s skill and the light load prevented a total disaster.load prevented a total disaster.–– used differential engine thrust for used differential engine thrust for

controlcontrol

http://en.wikipedia.org/wiki/Image:Ghana.airways.1.arp.750pix.jpg


•• June 27, 1972 Daniel Applegate, June 27, 1972 Daniel Applegate, Director of Product Engineering for Director of Product Engineering for ConvairConvair, the fuselage contractor, , the fuselage contractor, wrote a memo to his supervisors wrote a memo to his supervisors detailing potential problems of detailing potential problems of cargo door.cargo door.

•• The problem was first recognized The problem was first recognized in August 1969. The same thing in August 1969. The same thing had also happened in a ground had also happened in a ground test in 1970 (Ship1).test in 1970 (Ship1).

•• Recognized design flaws:Recognized design flaws:–– too few floor supports, defective latchtoo few floor supports, defective latch

http://www.airliners.net/open.file/129734/L/


•• Aft door failureAft door failure


Design ProcessDesign Process•• In designing the airframe, McDonnellIn designing the airframe, McDonnell--Douglas Douglas

chose to make the DCchose to make the DC--10 much like the older 10 much like the older DCDC--8 and DC8 and DC--9, two very successful and safe 9, two very successful and safe aircraft.aircraft.

•• PRO: PRO: –– sped up design processsped up design process–– Fit with Fit with ““an oftan oft--stated company policy of stated company policy of

technological cautiontechnological caution””•• CON: CON:

–– question as to whether same design principles question as to whether same design principles apply to wideapply to wide--body aircraftbody aircraft


More About the Design ProcessMore About the Design Process•• The DCThe DC--10 engineers were constrained by 10 engineers were constrained by

management to use the existing airframe technology management to use the existing airframe technology (which was not necessarily adequate for an aircraft (which was not necessarily adequate for an aircraft the size of the DCthe size of the DC--10) 10)

•• Both Boeing and Lockheed had made several Both Boeing and Lockheed had made several advancements in their airframe structural designs for advancements in their airframe structural designs for the 747 and the Lthe 747 and the L--1011, respectively.1011, respectively.–– These design advances were not proprietaryThese design advances were not proprietary

•• So one might argue that the accepted engineering So one might argue that the accepted engineering practice for building a jumbo jet was significantly practice for building a jumbo jet was significantly different from what McDonnelldifferent from what McDonnell--Douglas was doingDouglas was doing


Passenger Floor Supports:Passenger Floor Supports:•• Followed DCFollowed DC--9 format for number of floor supports.9 format for number of floor supports.•• In retrospect, this was relatively few floor supports In retrospect, this was relatively few floor supports

given the widegiven the wide--bodied nature of the plane.bodied nature of the plane.•• WHY? The principle of WHY? The principle of ““technological caution,technological caution,””

together with severe financial straits of the company together with severe financial straits of the company ““was apparently interpreted by its engineers to dictate was apparently interpreted by its engineers to dictate that corners be cut and existing Douglas technology that corners be cut and existing Douglas technology be used, even if it meant that some systems that be used, even if it meant that some systems that were rejected as inferior by its competitors would be were rejected as inferior by its competitors would be designed into the DCdesigned into the DC--10.10.””

DC 10 Cargo DoorDC 10 Cargo DoorCargoCargo--Door Latching SystemDoor Latching System•• 3 choices: Plug / Hydraulic / Electric3 choices: Plug / Hydraulic / Electric

–– Plug (DCPlug (DC--9) infeasible for larger door9) infeasible for larger door–– ElectricElectric

•• Lighter, fewer parts, easier to maintainLighter, fewer parts, easier to maintain•• Exerts pressure only when switched on; irreversibleExerts pressure only when switched on; irreversible•• If it fails to close completely, it holds more securelyIf it fails to close completely, it holds more securely•• but more catastrophic failure but more catastrophic failure –– sudden depressurization at high sudden depressurization at high

altitudealtitude–– HydraulicHydraulic

•• Heavier, more parts, harder to maintainHeavier, more parts, harder to maintain•• Continually exerts pressure; not irreversibleContinually exerts pressure; not irreversible•• If it fails to close completely, more frequent failuresIf it fails to close completely, more frequent failures•• but less catastrophic failures but less catastrophic failures –– less violent depressurization at less violent depressurization at

much lower altitudemuch lower altitude


•• Latch problem was Latch problem was that the door could that the door could appear to be latched appear to be latched but be prone to but be prone to failure due to failure due to differential pressuredifferential pressure

•• See animationSee animation

http://lessons.air.mmac.faa.gov/Lessons/reflib/an/

http://lessons.air.mmac.faa.gov/Lessons/reflib/an/


•• After the Detroit nearAfter the Detroit near--disaster, the NTSB disaster, the NTSB (National Transportation Safety Board) (National Transportation Safety Board) investigation revealed several problems and investigation revealed several problems and recommended immediate design changes. recommended immediate design changes.

•• The FAA did not follow NTSB The FAA did not follow NTSB recommendations. recommendations. –– FAA director John Shaffer and Douglas President FAA director John Shaffer and Douglas President

Jackson McGowan reached a gentlemanJackson McGowan reached a gentleman’’s s agreement to voluntarily fix the problemagreement to voluntarily fix the problem

–– no further official action was takenno further official action was taken

DC10 Cargo DoorDC10 Cargo Door

•• In July 1972, three In July 1972, three inspectors at Long inspectors at Long Beach plant certified Beach plant certified that Ship 29 had been that Ship 29 had been modified to fix modified to fix problemsproblems

•• Each affixed a stamp to Each affixed a stamp to the Shipthe Ship’’s paperwork s paperwork confirming the confirming the modificationsmodifications

•• The modifications, in The modifications, in fact, had not been fact, had not been made made

DC10 Cargo DoorDC10 Cargo Door

•• Two years later on March Two years later on March 3, 1974, after leaving Paris, 3, 1974, after leaving Paris, TK (Turkish Airlines) Flight TK (Turkish Airlines) Flight 981 (Ship 29) had its cargo 981 (Ship 29) had its cargo door blown off at 10,000 door blown off at 10,000 feetfeet

•• The result was a crash that The result was a crash that killed all 346 people killed all 346 people onboardonboard

http://upload.wikimedia.org/wikipedia/commons/7/70/Dc10-ta3a.png


Companies:Companies:•• McDonnelMcDonnel--Douglas was in precarious Douglas was in precarious

financial condition financial condition -- trying to beat the trying to beat the Lockheed L1011 to marketLockheed L1011 to market

•• ConvairConvair did not push too hard, since by did not push too hard, since by contract, they may have been held liable for contract, they may have been held liable for the costs of all design changesthe costs of all design changes

Were the companies negligent?Were the companies negligent?


Engineers:Engineers:•• Engineers pressed the matter through normal Engineers pressed the matter through normal

channels to the highest levels within both channels to the highest levels within both companies, but did not take it any furthercompanies, but did not take it any further

•• Standard operating procedure at McDonnell Standard operating procedure at McDonnell Douglas and Douglas and ConvairConvair was for engineers to was for engineers to defer to upper management, even though defer to upper management, even though they were aware of serious design flawsthey were aware of serious design flaws

Were the engineers negligent?Were the engineers negligent?


Others:Others:•• What about the three inspectors who certified What about the three inspectors who certified

that changes had been made?that changes had been made?•• What responsibility rests with the ground crew What responsibility rests with the ground crew

member(smember(s) who actually closed and latched ) who actually closed and latched the door?the door?

Were these people negligent?Were these people negligent?

Codes of EthicsCodes of Ethics

•• How do the current codes of ethics How do the current codes of ethics relate to each of these cases?relate to each of these cases?

•• What is the relationship between What is the relationship between negligence and ethical responsibilities?negligence and ethical responsibilities?

Other Major Engineering FailuresOther Major Engineering Failures

•• Interstate 35W Bridge, Minneapolis, MN (2007)Interstate 35W Bridge, Minneapolis, MN (2007)•• Columbia Space Shuttle (2003)Columbia Space Shuttle (2003)•• Challenger Space Shuttle (1986)Challenger Space Shuttle (1986)•• Kansas City Hyatt Regency Walkway Collapse, MO Kansas City Hyatt Regency Walkway Collapse, MO

(1981)(1981)•• Teton Dam (1976)Teton Dam (1976)•• Tacoma Narrows Bridge, WA (1940)Tacoma Narrows Bridge, WA (1940)

ethics: case studies · • • kansas city hyatt regency walkway collapse, mo (1981) • • teton...

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