march 1997 alerts - federal aviation administration · march 1997 improve reliability- ... (refer...

General AviationAirworthinessAlerts

AC No. 43-16

ALERT NO. 224MARCH 1997

Improve Reliability-Interchange ServiceExperience

A LER TS

Contents of this publication are informational only. Due to the need for extensive distribution of this publication,only one copy is provided to an addressee; however, this publication may be duplicated.

CONTENTS

AIRCRAFT

AMERICAN CHAMPION ..................................................................................................... 1BEECH ................................................................................................................................... 2CESSNA ................................................................................................................................. 4PIPER .................................................................................................................................... 7SOCATA ................................................................................................................................. 9

HELICOPTERS

AEROSPATIALE ................................................................................................................ 10BELL .................................................................................................................................... 11SIKORSKY ........................................................................................................................... 12

AGRICULTURAL AIRCRAFT

PIPER .................................................................................................................................. 13SCHWEIZER ....................................................................................................................... 13

AMATEUR, SPORT, AND EXPERIMENTAL AIRCRAFT

AEROSPORT ....................................................................................................................... 13GLASTAR ............................................................................................................................ 14HARALSON PERCEPTOR ................................................................................................. 14SX-300 .................................................................................................................................. 14TAILWIND .......................................................................................................................... 14ZENITH ............................................................................................................................... 15ZODIAC ................................................................................................................................ 15

PROPELLERS AND POWERPLANTS

McCAULEY ......................................................................................................................... 15

AIRWORTHINESS DIRECTIVES (AD’S)

ISSUED IN JANUARY 1997 .............................................................................................. 16

AIR NOTES

SUN ’N FUN ’97 ................................................................................................................... 17ALERTS ON LINE .............................................................................................................. 17FAA FORM 8010-4, MALFUNCTION OR DEFECT REPORT ........................................ 18SUBSCRIPTION REQUEST FORM .................................................................................. 18

March 1997 FAA AC 43-16

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FLIGHT STANDARDS SERVICEMike Monroney Aeronautical Center

The General Aviation Airworthiness Alerts provide a commoncommunication channel through which the aviation commu-nity can economically interchange service experience andthereby cooperate in the improvement of aeronautical productdurability, reliability, and safety. This publication is preparedfrom information submitted by those of you who operate andmaintain civil aeronautical products. The contents includeitems that have been reported as significant, but which havenot been evaluated fully by the time the material went topress. As additional facts such as cause and corrective actionare identified, the data will be published in subsequent issuesof the Alerts. This procedure gives Alerts’ readers promptnotice of conditions reported via Malfunction or DefectReports. Your comments and suggestions for improvement arealways welcome. Send to: FAA;ATTN: Maintenance Support Branch (AFS-640);P.O. Box 25082; Oklahoma City, OK 73125-5029.

U.S. DEPARTMENT OF TRANSPORTATIONFEDERAL AVIATION ADMINISTRATION

WASHINGTON, DC 20590

GENERAL AVIATION AIRWORTHINESS ALERTS

AIRCRAFT

AMERICAN CHAMPION

American Champion Rudder PedalModel 8KCAB FailuresSuper Decathlon 2720(Bellanca)

The owner of this aircraft reported a thirdrudder pedal failure in 298 hours of operation.

All of the rudder pedals (P/N 1537-1) failed atthe lower left corner and were installed in theleft forward position. The first failureoccurred within 147 hours of operation, thesecond within 86 hours of operation, and thethird within 65 hours of operation. Thisrudder pedal has three mounting pads on theback of the pedal through which the hinge pinpasses. (Refer to the following illustration.)

The submitter did not offer a conclusion as tothe cause of this defect and the short life of thepedals.

Part total times as previously stated.

FAA AC 43-16 March 1997

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BEECH

Beech Raw Fuel In TheModel 18 Cockpit

2840

After discovering the odor of fuel and raw fuelon the cockpit floor, the pilot made animmediate emergency landing. Fortunately,the fuel fumes did not find an ignition sourcebefore the aircraft was parked and evacuated.

An inspection revealed the aluminum fuel lineto the fuel pressure gauge had chafed against astringer until the wall thickness of the linewas penetrated. The submitter recommendedthe routing, support, and clearance of allcockpit pressure lines be closely checked atevery opportunity. This defect has beenreported several times in the past, on this, aswell as other make and model aircraft. It hasresulted in personal injury and substantialaircraft damage.

Part total time not reported.

Beech Main Landing GearModel C24R Actuator FailureSierra 3233

The pilot stated a loud abnormal “pop” washeard, followed by difficulty in maintainingdirectional control of the aircraft. The mainlanding gear “down-and-locked” light thenilluminated, and the landing gear controlhandle was placed in the “down” position.A safe landing was made.

Troubleshooting the system revealed the leftmain landing gear actuator (P/N 169-380060-1)piston was broken. The submitter speculatedthis failure was caused by improper rigging ofthe landing gear. This actuator had beenremoved and replaced a short time prior tothis occurrence. It was suggested the actuatorsand the landing gear system rigging beinspected at least annually.

Part total time-2,796 hours.

Beech Spar Carry ThroughModel F33 Structure CracksBonanza 5714

A submitter stated finding 16 aircraft withwing spar carry-through structural cracks.

These aircraft were outside the serial numberrange, and therefore not covered byAirworthiness Directive (AD) 95-04-03. Theseaircraft were used in a flight schoolenvironment which may have contributed tothe spar carry-through cracks. However, thisis a significant number of occurrences, and theinformation has been sent to the responsibleFAA aircraft certification office for possibleAD revision action. This defect may also affectother Bonanza models listed in AD 95-04-03.This information is provided to make allBonanza operators aware of the possibility ofdefects in the wing carry-through structure.The operating times on these 16 aircraftranged from 4,857 hours to 8,544 hours.

Part total times as previously stated.

Beech Defective FlexibleModel G35 PlumbingBonanza 2800/3242

All of the flexible fuel and brake hoses werefound defective during an annual inspection.

This has been a longstanding problem and hasbeen well-documented in many differentaviation publications. It has occurred on allmakes and models of aircraft using this typeplumbing. Flexible aircraft plumbing is notintended to, nor should it be expected to, last15, 20, 25 years or longer. It is hidden away inthe aircraft structure and is very oftenneglected until it fails. If failure occurs at acritical time during flight, it may lead topersonal injury and/or damage to the aircraft.It is suggested that during scheduledinspections, all flexible plumbing bethoroughly checked for condition andserviceability. When moved from its normalposition, it should not be rigid, stiff, or brittle.

The submitter of this report stated: “I think atime limit should be placed on these items.” In


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fact, most if not all, aviation installations offlexible plumbing are covered by a life limitestablished by the aircraft manufacturerand/or the hose manufacturer. It is criticalthat these life limits be complied with toensure continued airworthiness of theaircraft.


Beech Light DimmerModel K35 Rheostat/TransistorBonanza Failure

3310

All four of the lighting dimmer rheostat/transistor assemblies were found inoperativeduring an annual inspection.

The wiring to these controls was checked andfound in serviceable condition. The pottingcompound, forming each of the fourassemblies, had melted and dripped downonto the cockpit floor. The submitterspeculated this was caused by “excessive heatduring normal operation.” It was stated thisposes a safety hazard, and these assembliesshould be replaced with a unit which willhandle the electrical load and dissipate heateffectively. Some of the “older” pottingcompounds used for aircraft electricalinstallations have been found to break downand liquefy under conditions of age and heat.The newer potting compounds, now used inaviation, have been shown to endure theoperating environment to which they aresubjected.


Beech Propeller GovernorModel A-36 DefectBonanza 6122

It was reported that the engine would notdevelop full takeoff power (RPM).

An operational test of the system disclosedthe RPM indication at full throttle was only2,100. An inspection of the propeller systemrevealed the speed lever shaft was loose, andthe plastic end housing was cracked all theway around its base. This was a McCauley

propeller governor Model C29003-G/T23. It isrecommended this housing, as well as thegovernor installation and linkage, be closelyinspected at every opportunity.


Beech Wheel Brake FailureModel 58P 3242Baron

The pilot reported the right main landinggear strut “bottomed out” during landing, andthe right wheel brake failed.

An inspection disclosed the fitting(P/N AN837-4D) on the wheel brake cylinderwas cracked. Also, it was found that when themain landing gear strut was fully compressed,it made contact with the gear door linkassembly (P/N 35-805056-16) with sufficientforce to cause the brake cylinder fitting to fail.The submitter recommended that all 58 SeriesBarons with Cleveland brakes (30-93) beinspected for proper clearance in the areapreviously described.


Beech Cabin Heater FailureModel B60 2140Duke

The Janitrol Model B3040 heater wasreported inoperative, and the cabin smelled ofsmoke.

An investigation disclosed the cabinventilation blower was also inoperative. Thesubmitter speculated this caused anovertemperature condition in the heater.When the overtemperature switch tripped,instead of opening the 5 amp heat fuse, the 10watt, 3 ohm resistor burned and opened thecircuit. This resistor being open prohibitednormal function of the overtemperatureprotection circuit. The heater was shut downby the pilot, and no further damagedoccurred. Apparently, the resistor burnedbefore the fuse opened.



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Beech Cabin Smoke AndModel C90A Fuel FumesKing Air 2820

The flightcrew reported the cabin and cockpitfilled with smoke and fuel fumes duringtakeoff. The air-conditioning packs were shutoff, and the smoke and fumes dissipated. Aftera safe landing, the aircraft was delivered tomaintenance.

An investigation revealed the left fuel purgetank check valve (P/N 101-389011-65) wascontaminated. After replacement of the checkvalve, a test flight revealed no otherdiscrepancies. It was recommended thesecheck valves be added to the 12-month purgetank filter inspection for all King Air models.


Beech Engine ExhaustModel 300 CrackSuper King Air 7810

The right engine inboard exhaust stack(P/N 101-950017-1) was found cracked during ascheduled inspection.

The exhaust stack crack was approximately 10inches long and ran parallel and adjacent tothe horizontal weld seam on the forward side.The submitter stated this was the second newexhaust stack that had failed in 78 hours ofoperation. It was recommended that alloperators check for this condition at everyopportunity, especially just after a new part isinstalled.


CESSNA

Cessna Carburetor HeatModel 152 Valve SecurityAerobat 7322

An article concerning this subject waspublished in the December 1996 edition of thispublication. A reader responded to this article

and expressed his concerns and opinionsregarding this subject.

“This seems to be a continuous problemwhich has been propagated by installingscrews or aluminum rivets as a field repair.The carburetor heat valve plate and shaftis produced as an assembly (P/N 0450070-5), and the valve plate is installed on theshaft by Cessna using “stainless steel” (SS)rivets. Since it is an assembly, replacementrivets are not specified in themanufacturer’s part manual (figure 62). Itis necessary to contact Cessna to get thespecifications for these rivets and thenspecial order them. As everyone knows, SSrivets are not easily set, and the location ofthis installation makes it a much moredifficult task to properly set the rivets. Toinstall Number 6 screws requires enlargingthe holes in the shaft to .136 inch. If a one-eighth inch screw is used, the diameter ofthe screw shank (minus the amount lost forthe threads) is much less than the rivetinstallation. It should be obvious that SSrivets are substantially stronger thanaluminum rivets. In any case, theseinstallations are weaker than the originalSS rivet installation.

Aircraft owners and operators sometimesbecome upset when these facts arepresented to them. This has been carried tothe extent of “finding som eone w ho willsign it off.” Some people do not want tospend the extra money and time forreplacement with a factory assembled partor SS rivets. This puts you, as amaintenance technician, to a test of yourintegrity. Do you give the customer a letterdescribing the defect, make a log bookentry of this information, or “knuckleunder” to the economic pressure of losing acustomer? It’s your choice; however, Ipersonally would rather have an iratecustomer than one who was no longeraround to complain!”

Our thanks to the reader who submitted thissupporting and clarifying information of theprevious article.


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Cessna CarburetorModel 172N MalfunctionEngine Textron Lycoming 7322Model O-320H2ADSkyhawk

The pilot reported an engine power loss of 50percent was experienced during a local flight.A safe landing was made at the departureairport.

The Precision Airmotive carburetor(P/N 10-5135) discharge tube assembly(P/N 229-164) was found broken during aninspection. The discharge tube assembly hadbeen ingested into the engine. The submitterspeculated this caused solid particles ofcombustion material to be dislodged whichfouled the spark plugs. It is very important toconduct a visual inspection of the dischargetube assembly for security using theprocedures and tools referenced in thePrecision Airmotive Manual. This carburetorhas been superseded by a new carburetor(P/N 10-5217).


Cessna Main Landing GearModel 172RG FailuresCutlass 3230

Two separate reports stating failure of thesame part were received. One incidentinvolved failure of the right main landing gearto extend and lock and the other involved alike failure of the left main gear. Bothincidents resulted in “gear-up” landings.

All attempts to achieve a “down-and-locked”indication were futile. One of the incidentsoccurred during a training flight with multiple“touch-and-go” landings. At the time of failure,the respective brake was abnormally soft andspongy. In both cases, an investigationdisclosed the main landing gear pivotassembly had sheared at the base of thesplined surface. Evidently, the pivot assemblyhas been improved as there are two differentpart numbers (P/N’s 2441100-9 new numberand 2441100-1 old number) listed by themanufacturer. It would be wise for owners,

operators, and maintenance technicians ofthese aircraft to comply with all of themanufacturer’s service information concerningthis defect. It is also recommended this areabe given special attention during scheduledinspections.

One failure occurred at 1,611 operating hoursand the other occurred at 5,062 operatinghours.

Cessna Wing AttachmentModel 177B Fitting WearCardinal 5342

Movement between the left wing and thecenter wing attachment fitting was discoveredduring an annual inspection.

The center wing spar carry-through structure(P/N 1710703) is attached to the wing by pins.The amount of movement was measured at.0035 inch. The submitter stated there is nowritten manufacturer data for the maximumallowable wear at the wing-to-fuselage joints.It would be wise to give this area specialattention during scheduled inspections.


Cessna Defective LandingModel 182B Gear AttachmentSkylane 3211

One of the main landing gear “U-bolt” nuts wasfound loose during an annual inspection.

The right rear was loose and furtherinvestigation disclosed a pre-existing crack inthe “U bolt” which had allowed it to stretch.This leg of the “U bolt” was cracked throughapproximately 60 percent of its diameter. Thecrack was located three threads from theshank end of the threads, and this area wasadjacent to the location of the bottom of thenut when it was installed. The submitter didnot offer a cause for this defect; however,overtorque of this leg of the “U bolt” seems alikely cause.



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Cessna Wing Flap IndicationModel 182P Cable DamageSkylane 2751

The wing flap indicator cable was found frayedduring a 100-hour inspection.

The damaged section of the flap indicatorcable (P/N 0510105-231) was located just aft ofthe forward pulley under the floor and couldbe seen with the flaps in the full “down”position. With the flaps in the full “up”position, the cable became excessively “slack,”and the frayed portion was observedcontacting the forward side of the cockpitfloorboard hole through which it passed. Thishole is inside the center pedestal, and theforward side of the hole displayed signs ofchafing. The submitter suggested that the flapindicator cable be checked for chafing at thislocation through the entire range of flaptravel.


Cessna Fuel Line LeakageModel 310R 2820

Fuel stain was noticed on the left fuelcrossfeed line during an annual inspection.

The fuel stain was in the area where the fuelcrossfeed line (P/N 5200106-206) passedthrough the cabin at the main spar. This areais visible only with the upholstery removedfrom the cabin interior. Considerable laborwas required to remove and replace this fuelline. When the fuel line was removed, several“pinholes” were found to penetrate the wallthickness of the line. These “pinholes” wereverified by a pressure test of the line. Thesubmitter stated this damage was caused bycorrosion. There was no mention of fuel fumesin the cabin. This area should be checkedunder pressure at every opportunity,especially on high time or older aircraft.


Cessna Wing Doubler CrackModel 402C 5730Businessliner

A lower internal doubler (rib cap) was foundcracked on the left wing during a scheduledinspection.

The crack was located at Wing Station 106.79and was approximately 1.5 inches long. Itappeared the crack originated at the aft side ofthe landing gear door hinge cutout. Theadjacent lower wing skin was also cracked inthe same location. An inspection of the rightwing at the same location disclosed a similardefect. The submitter did not offer a cause forthis defect; however, due to the high numberof operating hours, metal fatigue and/orcorrosion may have been the most importantfactors. It is suggested this area be given closeattention during scheduled inspections.


Cessna Deice System DefectModel 550 3010Citation

The flightcrew reported the “surface deice”indicator light in the cockpit did notilluminate when the deice system bootsinflated.

An investigation revealed the pressureswitches (P/N 1106P55) were defective. Thesubmitter speculated the switches failed dueto water contamination from exposure to theweather. It was suggested the manufacturerconsider installing switches in a positionwhich would minimize their exposure towater.


Cessna Defective ToiletModel S550 2540Citation

A leak in the toilet unit was discovered whilecleaning the aircraft.


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Further inspection disclosed the toilet(P/N 17000-017) was leaking from the tank unit(P/N 17000-79) which had been improperlyrepaired. The toilet maintenance manual doesnot permit sealing of the tank unit. The tankunit should be replaced if found leaking. Toiletleakage has caused severe structural corrosiondamage to the aircraft. The toilet should bereplaced at the first sign of leakage.


PIPER

Piper Flexible FuelModel PA 28-140 Plumbing DefectCherokee 2820

All of the flexible fuel plumbing was founddefective when maintenance in the fuel tankarea was conducted.

The fuel vent hoses (P/N’s 63913-193and 63913-194) and the fuel supply hoses atthe fuel tank outlet were found “dry-rotted,very hard, and brittle.” The markings on thefuel supply hoses indicated they had beenmanufactured in 1972. Even though there wasno leakage from these lines, they held thepotential for failure at any time.

This type of report continues to come in at analarming rate, even after all of the publicitythis subject has received in the past. Alloperators and maintenance personnel areurged to comply with the life limitsestablished for these hoses by the aircraftand/or the hose manufacturer. Let’s try to put“prevention” back in preventive maintenance!Common sense dictates the necessity forspecial attention to the life limits of thesehoses.


Piper Wing Walk AreaModel PA 28-181 CracksArcher 5730

Multiple cracks were found on the forwardwing walk panel during a scheduledinspection.

The cracks were on the bottom of the forwardwing walk panel (P/N 62061-02) and werelocated at the inboard and outboard ends ofthe panel corrugations. This area is verydifficult to properly inspect. The submitterfound these cracks by using his hand anddragging his fingernails across the crackedarea. It was stated this was the sixth likeaircraft with this defect found by thesubmitter. These aircraft were engaged inflight training and had been in service forapproximately 5,000 hours of operation.Similar defects were found in the aft wingwalk panel (P/N 62061-04).


Piper Wing Ribs CrackedModel PA 28R-200 5712Arrow

While complying with Airworthiness Directive(AD) 95-20-07, cracks were found in anadjacent wing rib This rib was not covered bythe AD. (The AD requires inspection of theside brace stud).

The ribs (P/N’s 78475-004 left and 78475-005right), located at Wing Station 49.25, werecracked in the lower portion of the radius offorward flange. The side brace stud bracketassembly mounts on top of these rib flanges,making inspection of this area impossible withthis bracket installed. The same condition wasfound on both wings. It appeared the cracksoriginated at the bottom edge of the flangeradii and extended upward approximately 1inch.



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Piper Missing StiffenerModel PA 28R-201 5313Arrow

During a landing gear retraction test, bucklingof the skin in the area of the nose landing gearwheel well was noted.

Further investigation disclosed a stiffener(P/N 67972-02) was missing from the nose gearwheel well. There was no evidence that thestiffener had ever been installed. Thetechnical data indicated this aircraft, by serialnumber, should have the stiffener installed.This operator found one additional aircraft intheir fleet with the stiffener missing.

The manufacturers Service letter (SL)number 832, dated January 25, 1978, addressesthis subject and makes available a wheel wellstiffener kit (P/N 763-805V). SL 832 states:“The possibility exists when jacking up theaircraft under certain loading conditions thatbuckling may occur in the firewall when theforward jacking pad is utilized. To alleviatethis condition a wheel well stiffener kit hasbeen developed that when installed willprovide additional reinforcement of the wheelwell area.” It is suggested that all operators oflike aircraft conduct a one-time inspection forthe serial number applicability of SL 832 andthe presence of the subject stiffener.


Piper Aileron Hinge CrackModel PA 32-300 5751Cherokee Six

The left outboard aileron hinge bracket(P/N 62372-01) was found broken during anannual inspection.

The hinge bracket was cracked completelythrough at the spar side. This defect waslocated in the radius area of the bracketadjacent to the mounting fastener holes. Thisis an area subjected to stress loads imposed byhigh wind gust on the parking ramp andoperational stress during violent or sudden

movement of the flight controls. Closeattention should be given to this area duringscheduled inspections.


Piper Fuel Line DamageModel PA 34-200 2820Seneca

The main fuel lines (P/N’s 95153-27 leftand 95153-28 right) were found severelychafed during other related maintenance.

Both fuel lines were chafed throughapproximately 90 percent of their wallthickness. The lines were chafing against acabin heat duct (P/N 63633-91) in the aftnacelle of each engine. Proper inspection ofthis area requires removal of the aft nacelletop panel, and the use of a flashlight andmirror to examine the aft outboard corner.(This is where the fuel line passes under thecabin heat duct.) If chafing is found, the fuelline should be replaced, if necessary, orrepositioned to provide clearance, and shouldhave chafe protection installed.


Piper Defective NoseModel PA 34-200T Landing GearSeneca Steering

3251

The nose landing gear steering system wasfound damaged during an annual inspection.

When the two bolts (P/N AN4-7A) used toattach the nose steering channel wereremoved for inspection, one bolt was crackedthrough approximately 75 percent of the shankdiameter, and the other bolt was bent. It wasthe submitter’s opinion that this damage wasthe result of exceeding the towing limitsduring ground movement of the aircraft.



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Piper Fuel Pump FailureModel PA 34-200T 2822Seneca

It was reported that the left engine fuel pumpwould not work in the “low” position.

An inspection disclosed the fuel pump wouldnot work on the “low” setting and was noisy inthe “high” setting. High resistance in thepump motor was found while troubleshootingthis problem. It was believed the resistor,which is used to control the high and lowsettings, failed. When the fuel pump wasremoved and shaken, a “clunking” sound washeard. The fuel pump was disassembled, fuelwas found in the motor, and the field windingwas loose.

Needless to say, this condition presented avery hazardous situation which had thepotential of causing a catastrophic event. Anyfuel pump anomaly should be immediately andthoroughly investigated.


Piper Nose Gear SteeringModel PA 34-220T FailureSeneca 3251

The pilot heard a loud and abnormal “banging”sound while taxiing from the parking ramp tothe runway. The “banging” seemed to comefrom the nose landing gear. The pilotcontinued to the end of the runway, and atakeoff was made. The landing gear was notretracted because the pilot noticed in the“nose gear position mirror” that the nose gearwheel was turned 90 degrees to the aircraft.A safe landing was made without the aid ofnose gear steering, and the aircraft wasrecovered from the runway.

An investigation revealed the structuralchannel (P/N 95061-28) had several cracks onboth sides at the aft end. These cracks allowedthe nose gear steering ball to exit the channel.This disabled the nose gear steering function.It would seem that a prudent pilot would have

returned to the parking ramp when the“banging” noise was heard rather than placingthe aircraft and its occupants at risk.


Piper Elevator StructuralModel PA 42-1000 DamageCheyenne 400LS 5520

Three cracks were found in the elevator skinafter the paint was removed from the elevatorusing a chemical stripper.

The cracks were located adjacent to thechannel used to mount the elevatorcounterweight and ran in an aft direction. Twomore cracks were found in the skin at thestringer aft of the channel. Further inspectionthrough the access panel revealed the stringerwas broken. It appears the elevatorcounterweight imposes great stress, at thepoint where it is mounted, during strong andgusty wind conditions and possibly duringextreme flight conditions. This area deservesspecial attention during scheduledinspections.


SOCATA

Socata Main Landing GearModel TB-9 FailureTampico 3210

The left main landing gear wheel skiddedduring landing, causing the aircraft to turn leftand slide to a stop. There were no injuries, andthe aircraft was recovered from the runway.

An inspection revealed the left main landinggear scissors (P/N TB1041033000) had broken,allowing the wheel to turn sideways. Thescissors broke on the lower half, adjacent tothe strut attachment point. It appeared thefracture was the result of a pre-existing crackon the outboard side of the scissors fitting. Theattachment pins (which hold the scissors) wereseverely corroded, and there was no evidence


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of lubrication. Also, the grease fitting wouldnot accept grease, and the scissors wereextremely difficult to move. The submitterspeculated this caused excessive stress on thescissors assembly, and led to this failure.(Refer to the following illustration.)


Socata Flight Control YokeModel T-9 DefectTampico 2701

Both the left and right flight control yokeassemblies were found cracked during ascheduled inspection. Three separate reportson like aircraft were received stating the samedefect.

The cracks were located in the bend radii ofthe aft flange support halves(P/N’s TB10 23012100 and TB10 2301201).(Refer to the following illustration.) One sideof the flange was severed, and the other sidewas very close to failure. These cracks areimpossible to see without lifting the pilot’sinstrument panel. It was the submitter’sopinion that this damage was caused by thetransfer of wind gust loads from the controllock assembly.

Part total time-3,470 hours. The other twooccurrences were at 2,885 hours and 2,970hours.

HELICOPTERS

AEROSPATIALE

Aerospatiale Tail Rotor PitchModel AS 350B2 Control Rod FailureEcureuil 6711

The helicopter crashed into an offshoreplatform in the Gulf of Mexico afterexperiencing a high frequency vibration andloss of tail rotor effectiveness.

One of the tail rotor pitch control rods(P/N 350A33-2145-00 or -01) was found brokenduring an investigation. The spherical bearinginstalled in that control rod displayedexcessive wear. (Refer to the followingillustration.) There are two part numbercontrol rods eligible for installation on thisaircraft, and the exact part number installedwas not known. At the time of this report, itwas not known if the bearing or the control


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rod failed first; however, it was speculatedthat the worn bearing set up an abnormalvibration which caused the tail rotor pitchcontrol rod to fail.


BELL

Bell Vertical Fin FailureModels 204B, 205A, During External Load205A-1, 205B and OperationsUH-1 5500

Information for the following article wasfurnished by the National TransportationSafety Board (NTSB) and the FAA’s RotorcraftCertification Directorate (ASW-110) located inFort Worth, Texas. (The following article hasbeen printed as it was received.)

As the result of a noninjury aircraftaccident, the FAA and the NTSB havediscovered a structural deficiency in thevertical fin of the helicopter modelspreviously mentioned. This deficiency maylead to structural failure and/or separationof the vertical fin. Metallurgicalexaminations have revealed the vertical finforward spar may be subject to failurethrough the Number 1 rivet hole. Thefailures appear to result from high cyclefatigue which is consistent with short cycle

heavy lift operations. The number of cycles(defined as maximum power applications)were not available.

The helicopter involved in this accidenthad been fitted with the latest designvertical fin spar, which was installedduring manufacture. While definitivenumbers cannot be determined, initialcalculations suggest the aluminum verticalfin spar has an ultimate life ofapproximately 200,000 heavy lift, maximumpower cycles. Any damage to rivet holesduring tailboom repair, or evidence ofworking rivets has been demonstrated tofurther reduce the ultimate life of the spar.Heavy external lift at gross weight orabove, “snatching” loads off the ground,applying full right pedal to unload the tailrotor to achieve additional main rotor lift,and jerking loads airborne, all contribute toshorter ultimate life of the antitorquestructure.

Airworthiness Directive (AD) 71-21-02previously addressed this subject onModels 205A and 205A-1 and further ADaction is contemplated. The FAA recommendsthat operators pay special attention to thevertical fin spar cap and inspect thediscrepant area before the first flight of eachday until more effective corrective action isavailable. (Refer to the following illustration.)


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Bell Door Lock CautionModels 222 B, U, Lights Flickerand 230 5210

The following article was submitted by theFAA’s Rotorcraft Certification Office(ASW-170) located in Fort Worth, Texas.

The applicable aircraft models and serialnumbers referenced in the following TechnicalBulletin Numbers (TBN) follow:

Bell Model 222 (S/N 47006 through 47089) andBell Model 222B (S/N 47131 through 47156),TBN 222-96-155.

Bell Model 222U (S/N 47501 through 47574),TBN 222U-96-83. Bell Model 230 (S/N 23001through 23038).

All of the above TBN’s were datedAugust 30, 1996.

These TBN’s advised of reports that thepassenger door lock caution lights will flickerduring flight. The intermittent caution lightflicker is a result of fuselage flexing commonto normal flight regimes. The TBN’s giveinformation on installing an improved switchwhich will eliminate any further occurrence ofthis problem.

Bell Tail Rotor DriveModels UH-1, AH-1S, Shaft HangerAH-1G, AH-1J, AH1Q, Bearings205A-1, 204B, 6510205B, 212, and 412

The following article was submitted by theFAA’s Rotorcraft Certification Office(ASW-170) located in Fort Worth, Texas. (Thisarticle is printed as it was received.)

UNAPPROVED TAIL ROTOR DRIVESHAFT HANGER BEARINGS

Bell Helicopter Textron, Inc., (hereafterreferred to as Bell Helicopter) has recentlylearned that a number of tail rotor driveshaft hanger bearings were made available

to operators identified by invalid BellHelicopter Part Numbers 204-040-623-105/-107. These bearings were sold by thebearing manufacturer to the CanadianGovernment, but could possibly have beendelivered to other users as well. Thesubject bearings were procured as directreplacement parts for those supplied byBell Helicopter under P/N 204-040-623-003or -005.

The Bell Helicopter “APPROVED ANDQUALIFIED” part number bearings have atwo-piece, spot-welded cage. The INVALIDpart number bearings have a two-pieceriveted cage. The bearings having theriveted cages do not meet source controlrequirements, and have not undergone BellHelicopter qualification testing. Bearingsnot meeting these requirements areunapproved parts and are not authorizedfor use by Bell Helicopter.

Bell Helicopter has issued Operations SafetyNotice OSN GEN-96-29 which addresses thisproblem. Upon request, copies of this noticemay be obtained from: Bell HelicopterTextron, Inc.; P.O. Box 482;Fort Worth, TX 76101.

SIKORSKY

Sikorsky Improperly ThreadedModel S76A Tail Rotor CableMark II 6720

While attempting to install a new tail rotorcable, the technician discovered the threaded“male” end of the cable was threadedimproperly. The cable was threaded withleft-hand threads instead of the requiredright-hand threads. The operator found nineother cables in their stock that were threadedincorrectly. The cables were all purchaseddirectly from an authorized Sikorsky partsdistributor and included Sikorsky packaging.

Part total time-“0” hours.


13

Sikorsky Ruptured HeaterModel S-76C Duct Elbow

2140

A customer complained of hot air exiting thebaggage compartment when baggage was beingunloaded in cold weather.

An inspection of the baggage compartment wasinitiated, and it was discovered that the centeroverhead baggage shroud C-4 heater ductelbow (P/N BWT13671-1) had rupturedallowing hot air from the heater to enter thebaggage compartment.

Part total time-126 hours.

AGRICULTURAL AIRCRAFT

PIPER

Piper Wheel Bolt FailureModel PA 25 3246Pawnee

One of the wheel half bolts was found brokenwhen the left wheel cover was removed duringan annual inspection.

The nut and threaded end of the bolt werefound inside the wheel cover, and the headend of the bolt was missing. Approximately1 year prior, the tires were installed, and thesubmitter speculated the broken bolt was“overtorqued” at that time. It was stated thesebolts (5/16 by 24) are easily “overtorqued” andcare should be taken to avoid excessive torque.


SCHWEIZER

Schweizer Wheel Brake FailureModel G-164A 3242Ag Cat

The pilot reported that while turning theaircraft, using the left wheel brake, the pedal

suddenly tipped forward beyond the normalposition. The left brake was no longereffective.

An investigation disclosed the three screwsused to attach the left brake master cylinderhad “ripped out” of the master cylinder base.This disconnected the master cylinder andmade the left brake ineffective. This conditioncan also affect the rudder operation becausewhen the pedal “flips” forward, rudder pedaltravel is limited. The submitter stated thethree screws mounting the master cylinder aresafety wired when installed, and their propertightness ensures security of the cylinder.


AMATEUR, SPORT, ANDEXPERIMENTAL AIRCRAFT

AEROSPORT

Aerosport Magneto FailureModel II 7414

A rebuilt magneto (Bendix S-4RN-21) on aLycoming O-320-E2A engine failed after only 7hours of operation.

At high RPM, the left magneto drop indicateda loss of 200 RPM. At lower RPM’s, there wasno indication of a drop in RPM’s. The enginefelt rough in flight and missed at 1,700 RPM’sand higher .

The submitter stated that after extensivetroubleshooting, the left magneto was found tobe the source of the problem. The magneto wasdisassembled, and all new parts were installed(coil, points, and capacitor). It was alsodiscovered during disassembly that thecapacitor (P/N ES10-51676) had loose internalparts. After replacement of these parts andreassembly, the magneto performed correctly.



14

GLASTAR

Glastar Rudder SkinModel III Concaved

5542

At an airspeed of approximately 120 miles perhour, the rudder would “walk,” and at higherairspeeds, the “walking” action became moreviolent.

An inspection of the rudder revealed therudder skin was slightly concaved. The rudderwas removed, and the trailing edge wassqueezed in a press brake. This eliminated theconcave shape. A flight test of up to 150 milesper hour determined that the problem nolonger existed. The submitter stated theconstruction manual calls for an inspection ofthis condition and details the correctiveprocedure to be taken.


HARALSON PERCEPTOR

Haralson Perceptor Fuel Header NotVented2810

An incident occurred when the fuel headertank did not vent properly.

This caused the fuel header tank to developnegative pressurization and starve the engineof fuel. A fuel vent was properly installed,which solved the problem.


SX-300

SX-300 Cracked HydraulicActuator3233

The pilot discovered, during flight, that theright main landing gear would not lock in the“retracted” or “extended” position. The rightmain landing gear collapsed during landing,and caused the aircraft to skid off the runway.

The submitter stated the hydraulic actuatorrod-end had apparently begun to crack;however, it went undetected until it failedduring the last takeoff. The submitterrecommended that, in the future, frequent andmore thorough inspections be performed inthis area.


TAILWIND

Tailwind Occupant RestraintModel W-8 Failure

2560

The aircraft crashed due to an engine failure.During impact, the occupant restraint systemfailed causing the occupant to impact theinstrument panel.

While inspecting the aircraft, the restraintsystem attachment point to the airframe wasfound broken. The available evidenceindicated the attachment lugs broke at thepoint where they were welded to the airframedue to inadequate or improper weldingtechnique. (Refer to the following illustration.)It was recommended that amateur aircraftbuilders ensure that all welding procedures


15

are done properly. If you are not proficientwith welding processes, you should hire aprofessional.


ZENITH

Zenith Broken Rotary ValveModel CH-701 GearEngine Model Rotax 582 8520

The rotary valve gear (P/N 935-730) oil sumpfasteners failed, which allowed the oil sump todrop below the engine crankshaft. Lack oflubrication from the sump caused the brassrotary valve to “shear off” its teeth, whichresulted in the rotary valve slipping andbecoming “out of time” with the engine. Also,this condition caused engine roughness and apower loss.


ZODIAC

Zodiac Separated NicopressModel CH-600 Sleeve

2730

A 28-3M Nicopress sleeve was incorrectlyinstalled, which caused the elevator cable toseparate, thereby, disabling elevator control.

This sleeve is located at the forward end of thecable next to the control stick. The submitterrecommended that flight control cableconnections be installed using two sleeves(like those found on most manufacturedaircraft).


PROPELLERS ANDPOWERPLANTS

McCAULEY

McCauley AirworthinessModel 2A36C23-P-E Directive

Clarification6114

A safety recommendation has been submittedby Mr. Lyle Alexander, an AirworthinessInspector with the FAA’s Flight StandardsDistrict Office (FSDO) located in Scottsdale,Arizona. (This article has been printed as itwas received from the Scottsdale FSDO.)

This safety recommendation (number notyet assigned) was submitted due tocatastrophic propeller hub failure at thepoint of rotation during the takeoff roll.This propeller was installed on a Beech,Model N35 aircraft. The pilot lost control,the aircraft veered off the runway, flippedover, and was destroyed. The three aircraftoccupants suffered only minor injuries.


16

Had this occurred after the aircraft becameairborne, the personal injuries wouldsurely have been more severe.

An examination revealed the propellerfailed at the hub, forward of theattachment flange around the hubcircumference. This caused the propeller toinstantaneously separate from the aircraft.

While researching the aircraft records, itwas determined that there was nocompliance with Airworthiness Directive(AD) 89-26-08. The investigator alsodetermined this AD was not applicable tothis particular propeller. The applicabilitysection of the AD states that the ADapplies to McCauley propellerModels 2A36C23/84B-0. A representative ofthe manufacturer was contacted andoffered the following statement:“AD 89-26-08 does apply to the failedpropeller.” It was explained the “84B-0” atthe end of the model number, as written inthe AD, refers to the blade design.

A copy of AD 89-26-08, along with thepropeller model designation 2A36C23-P-E,was presented to several Certified AircraftMechanics, Inspection Authorization (IA’s),and FAA Airworthiness Inspectors.Without knowing the circumstances behindthis, they were asked if the AD wasapplicable to this propeller model number.All said, without exception, the AD was notapplicable because of the “/84B0”designation at the end of the modelnumber. This aircraft had undergone fiveannual inspections, completed by two IA’sand a Certified Repair Station since theeffective date of the AD. When asked whythis AD had not been complied with, theyall stated it was not applicable by modelnumber.

It has been determined that thisAirworthiness Directive 89-26-08, doesdefinitely apply to all McCauleypropeller Models 2A36C23 (withoutregard to subsequent figures,

numerals, or letters) and 2A36C82(without regard to subsequent figures,numerals, or letters).

This ambiguity in the AD may have beenthe cause for noncompliance of the AD andthe subsequent propeller failure. Theremay be many other like propellers inservice which do not have this ADcomplied with for the same reason. Allowners, operators, and maintenancepersonnel are strongly encouraged toreview the aircraft records and takeappropriate action to ensure compliance. Ifthere is any doubt concerning theapplicability of any AD, contact the FAAaircraft certification office or themanufacturer prior to releasing theaircraft for service. The address for theFAA aircraft certification office is listed inthe AD. Also, the AD refers to McCauleyService Letter (SL) 1989-5 which is moreclearly written as to the applicability. It isbelieved that numerous unsafe propellersare being operated because of the modelnumber disparity.

This AD may be applicable, but is notlimited to, propellers installed on BeechModel 33 and 35 series aircraft.

AIRWORTHINESS DIRECTIVES(AD’S)

ISSUED IN JANUARY 1997

(For Small Aircraft, Rotorcraft, and Engines)

97-01-02 Cessna 525; MLG trunnion pins.

97-01-01 Piper PA24, PA28R, PA30,PA32R, PA34, and PA39 Series;main gear sidebrace studs.

97-02-02 Fairchild SA26, SA226, andSA227 Series; pitch control.


17

97-01-13 Cessna 100, 200, 300, and 400Series; hose wrap.

97-02-01 Piper PA-31T2; rerouting landinggear emergency extension line.

97-03-01 Raytheon (Beech) 1900D;right-hand exhaust stack.

97-03-02 Sailplanes: Glasflugel H301,H301B, Libelle 201B, Club,Libelle 205, Kestrel; controlsurface weight.

97-01-05 Williams FJ44-1A turbofanengines; disk blade retention.

97-01-03 Textron Lycoming ReciprocatingEngines; piston pin removal.

96-26-01 General Electric Engines CT7Series Turboprop Engines; gasgenerator turbines.

96-25-20 Hamilton Standard 14RF and14RF Series, and Model 6/5500/FPropellers; critical controlcomponents.

97-01-06 Bell restricted category HH-1K,TH-1F, TH-1L, UH-1A, UH-1B,UH-1E, UH-1F, UH-1H, UH-1L,and UH-1P helicopters; tail rotorslider.

97-02-14 Robinson R22 Helicopters;throttle governor.

97-02-15 Robinson R44 Helicopters; RPMwarning unit.

AIR NOTES

SUN ’N FUN ’97

The 1997 SUN ’N FUN EAA InternationalAviation Convention/Airshow/Fly-In isscheduled for April 5 through April 12, 1997,

at Lakeland Linder Airport in Lakeland,Florida.

The FAA Safety Center auditorium will hostforums and seminars throughout the airshow.There will also be presentations from most ofthe major aviation organizations which willcover the entire gamut of general aviationactivities and interests. The staff of thispublication will occupy a booth in the FAASafety Center. We will have literature andinformation concerning the Service DifficultyReporting (SDR) Program and the services andproducts available to the aviation public. Welook forward to another excellent event andhope to see you.

ALERTS ON LINE

We have received several requests to make theinformation contained in AC 43-16, GeneralAviation Airworthiness Alerts, availableelectronically. Therefore, this publication isnow available through the FedWorld BulletinBoard System (BBS), via the Internet.

You may directly access the FedWorld BBS attelephone number (703) 321-3339. To accessthis publication through the Internet, use thefollowing address.

http://www.fedworld.gov/ftp.htm

This will open the “FedWorld File TransferProtocol Search And Retrieve Service” screen.Page down to the heading “Federal AviationAdministration” and select “FAA-ASI”. The filenames will begin with “ALT”, followed bythree characters for the month, followed bytwo digits for the year (e.g. “ALTJUN96.TXT”).The extension “TXT” indicates the file isviewable on the screen and also available todownload.

Beginning July 1996, we are using the AdobeAcrobat software program format to uploadthis monthly publication. This change isnecessary to include the illustrations whichare associated with various articles. The file


18

names will still begin with “ALT”, followed bythree characters for the month, followed bytwo digits for the year; however, the extensionwill be “PDF” (e.g. “ALTJUL96.PDF”).The extension “PDF” indicates it will benecessary to download the files for viewing.The Adobe Acrobat Viewer is available fordownload from the Internet (free of charge)and will allow the files to be read.

You may still access the “TXT” extension forissues of this publication prior to July 1996.

Also, available at this address are the ServiceDifficulty Reports which may be of interest.

The Regulatory Support Division (AFS-600)has established a “HomePage” on the Internet,through which the same information isavailable. The address for the AFS-600“HomePage” is:

http://www.mmac.jccbi.gov/afs/afs600

Also, this address has a large quantity of otherinformation available. There are “hot buttons”to take you to other locations and sites whereFAA Flight Standards Service information isavailable. If you have any questions, our“E-mail” address follows.

Other requests have been received indicatinga need to make the staff of this publicationmore available to our readers. To providegreater and more flexible access for you tooffer information and ask questions, you maycontact us by using any of the followingmethods.

Editor: Phil Lomax, AFS-640

Telephone Number: (405) 954-6487

FAX Number: (405) 954-4570 or(405) 954-4748

Internet E mail address: [email protected]

Mailing Address:FAAATTN: AFS-640 (Phil Lomax)P.O. Box 25082

Oklahoma City, OK 73125-5029

We hope this will allow you to contact us bya means which will be convenient and savesome of your time. We welcome the submissionof aircraft maintenance information via anyform or format. This publication provides anopportunity for you to inform the generalaviation community of the problems you haveencountered. The Service Difficulty Reporting(SDR) program also brings the problems to theattention of those who are able to resolve theproblems. Your participation in the SDRprogram is vital so accurate maintenanceinformation is available to the general aviationcommunity.

FAA FORM 8010-4, MALFUNCTION ORDEFECT REPORT

For your convenience, FAA Form 8010-4,Malfunction or Defect Report, will be printedin every issue of this publication.

You may complete the form, fold, staple, andreturn it to the address printed on the form.(No postage is required.)

SUBSCRIPTION REQUEST FORM

For your convenience, a Subscription RequestForm for AC 43-16, General AviationAirworthiness Alerts, is printed in everyissue.

If you wish to be placed on the distributionlist, complete the form, and return it, in astamped envelope, to the address shown onthe form.

Use this space for continuation of Block 8 (if required).

Federal Aviation AdministrationAFS-640 (Alerts)P.O. Box 25082Oklahoma City, OK 73125-5029

SUBSCRIPTION REQUEST FORMADVISORY CIRCULAR (AC) 43-16, GENERAL AVIATION AIRWORTHINESS

ALERTS

Please use this request to subscribe to AC 43-16 or to change your address if you are presently on the mailinglist. Once your name has been entered, you will continue to receive this publication until you request your namebe removed or a copy is returned because of an incorrect address.

Because this mailing list is independent of other FAA mailing lists, it is necessary that you notify us when youraddress changes. (Our address is on the following subscription request.) If you are presently receiving thispublication it is NOT necessary to send another subscription request. The following subscription request may beduplicated, as necessary. TELEPHONE REQUESTS WILL ALSO BE ACCEPTED; THE TELEPHONENUMBER IS (405) 954-6487. THE FAX NUMBERS ARE: (405) 954-4748 and/or (405) 954-4570.

AC 43-16 SUBSCRIPTION REQUEST

If you would like to BEGIN receiving AC 43-16, orCHANGE your address, please complete the following:

PLEASE PRINT INFORMATION LEGIBLY,INCLUDE YOUR ZIP CODE, AND THE DATEOF YOUR REQUEST.

NAME:

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CIRCLE ONE OF THE FOLLOWING:

1. This is a NEW subscription.

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SEND ONLY ONE SUBSCRIPTION REQUEST TOTHE FOLLOWING ADDRESS:

FAA, Regulatory Support DivisionATTN: AFS-640 (Phil Lomax)P.O. Box 25082Oklahoma City, OK 73125-5029

If you require more than one copy of AC 43-16, it may be reproduced.

U.S.Departmentof Transportation

Federal AviationAdministration

Maintenance Support BranchATTN: ALERTS, AFS-640P.O. Box 25082Oklahoma City, OK 73125-5029

AFS-640

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