january 1997 alerts - federal aviation administration€¦ · cessna cessna rudder spar cracks...

General AviationAirworthinessAlerts

AC No. 43-16

ALERT NO. 222JANUARY 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

AIRPLANES

BEECH ................................................................................................................................... 1CESSNA ................................................................................................................................. 4GENERAL AVIA COSTRUZIONI ....................................................................................... 9PIPER .................................................................................................................................... 9SABRELINER ..................................................................................................................... 12STINSON ............................................................................................................................. 12

HELICOPTERS

BELL .................................................................................................................................... 13MCDONNELL DOUGLAS .................................................................................................. 14

AMATEUR, EXPERIMENTAL, AND SPORT AIRCRAFT

EDGE ................................................................................................................................... 15

HOT AIR BALLOONS

HEAD ................................................................................................................................... 15

PROPELLERS AND POWERPLANTS

TELEDYNE CONTINENTAL ............................................................................................ 15

ACCESSORIES

DEFECTIVE AVIATION HOSES ...................................................................................... 16

AIR NOTES

ALERTS ON LINE .............................................................................................................. 16A TRIBUTE TO THE FORGOTTEN MECHANIC ........................................................... 18FAA FORM 8010-4, MALFUNCTION OR DEFECT REPORT ........................................ 19SUBSCRIPTION REQUEST FORM .................................................................................. 19

January 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

AIRPLANES

BEECH

Beech Flight ControlModel C23 Cable DamageSundowner 2730

The stabilator control cable was found withbroken strands during a scheduled inspection.

The stabilator “down” cable(P/N NAS 314-25-1411) was frayed with manybroken strands at the forward pulley locatedjust aft of the firewall and under the controlcolumn. (Refer to the following illustration.)The most likely cause of this defect was ageand a high number of cycles. This areadeserves close attention during scheduledinspections and maintenance.

Part total time-5,572 hours.

FAA AC 43-16 January 1997

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Beech Main Landing GearModel 35 FailureBonanza 3213

Maintenance technicians heard a loudexplosive-like noise while working on theparking ramp. The noise appeared to comefrom an aircraft parked nearby.

An investigation disclosed the left mainlanding gear strut was bottomed out, andthere was a large hole in the top of the wing.It was later determined the landing gear strutsnapring (P/N NAS 50-200) became disengagedfrom the groove. This allowed the strut endplug (P/N 45-815224) to be propelled from thetop of the strut with great force, penetratingthe upper wing surface. During discussionswith the manufacturer, it was learned thereare three possible causes for this type offailure.

1. A snapring with the wrong part numberwas used. 2. The snapring was installed upside down(i.e. with the “beveled side” up). 3. During installation, the snapring wasdistorted.

It was fortunate that this happened while theaircraft was parked on the ramp since in theretracted position the top of the strut is2 inches from, and aimed directly toward, theauxiliary fuel tank.

Estimated part total time-3,187 hours.

Beech Nose Landing GearModel A36 FailureBonanza 3230

After a normal landing, the nose landing gearcollapsed while the aircraft was being slowed.

The aft nose landing gear retraction rod(P/N 36-820011-3) was found broken during aninvestigation. The retraction rod brokeapproximately 1 inch into the threadedportion. This is the point where the rod-endthreads terminated. The cause of this failure

was not given by the submitter. It would bewise to check this area very closely duringscheduled inspections and maintenance.


Beech Vacuum SystemModel 58P Failure

3700

The pilot stated the vacuum system pressurewent to zero during flight.

An investigation disclosed the drive shaft wassheared on the vacuum pumps. Both pumpsand their filters were replaced. The submitterspeculated that one of the pumps had beeninoperative for some time; therefore, thesystem demand was placed on the remainingpump. The vacuum pumps should beindividually checked for operation duringscheduled inspections.

Part total time-490 hours.

Beech Nose Landing GearModel 76 FailureDuchess 3230

When engine power was applied for takeoff,during a “touch-and-go” landing, the noselanding gear collapsed.

An investigation disclosed severaldiscrepancies which contributed to this event.

1. The left forward drag brace attachmentbolt was loose. 2. The incorrect nut, cotter pin, andwashers were installed. 3. The “downlock” hook pivot bolt was verystiff and almost seized which caused the hookto operate very slowly. 4. The pivot bolt and bushings between theupper and lower drag braces were severelyworn at the “downlock” assembly. 5. The nose gear “downlock” switch was notproperly adjusted. 6. It appeared the nose gear assembly hadnot been lubricated for a long time.


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This accident should not have happened!It would appear the aircraft was sufferingfrom severe neglect!

Part total time not reported.

Beech Main Landing GearModel C90A Structural DefectsKing Air 3230

Cracks were found in the right main landinggear cylinder support brackets during ascheduled inspection.

The inboard cylinder support bracket(P/N 90-120060-94) and the outboard cylindersupport bracket (P/N 90-120060-92) werecracked through approximately 50 percent oftheir length. These cracks were observed“opening wide” during a retraction test. It wasevident these cracks would have progressed tothe point of separation very soon. A completeinspection of this area is critical to safeoperations and should be accomplished duringscheduled inspections and regularmaintenance.


Beech Entrance DoorModel A100 Support StructureKing Air Cracks

5323

The cabin entrance door supporting structurewas found cracked during a scheduledinspection.

The cabin door cable post bracket intercoastal(P/N 50-430043-1259) was found severelycracked and distorted. The submitterspeculated this damage was caused by“overloading the door.” This seems to be acommon occurrence which results when twoor more passengers, being in a rush to exit theaircraft, place their weight on the door stairs.The exit door stairs are not designed toaccommodate more than one person at a time.The submitter suggested the aircraftmanufacturer design a structure which willbear these excessive loads. This problem couldalso be averted by the flightcrew instructingthe passengers on the proper entrance and

exit procedures and by monitoring andassisting the passengers during thisprocedure. The high number of operatinghours on this part may have been a significantcontributing factor in this failure. Thisproblem seems to be prevalent in all King AirModels.


Beech Generator FailureModel B200 2421King Air

Maintenance personnel were notified theright engine generator failed during flight.

An initial check of the system showed allcomponents functioning properly. Furtherinvestigation disclosed high resistance frompin 33 on relay panel A123 to pin B at thegenerator control unit (GCU). The cause wasfound in wire number P41R16 which wasrouted in a bundle from the relay panel to theGCU. This wire had been stamped by alabeling machine, which made an indentationin the shielded wire, and apparently allowedarcing to occur. The conductor was eventuallyburned through which was revealed by thehigh resistance indication. The systemfunctioned normally after wire numberP41R16 was repaired.


Beech Cowling Ice VaneModel 300 Door BrokenKing Air 3080

A section of the left cowling ice vane door wasfound missing during a scheduled inspection.

The missing section of the door(P/N 101-910123-23) was approximately4- by 8-inches. (Refer to the followingillustration.) A foreign object damage (FOD)inspection of the engines first stagecompressor revealed one blade edge was bentand torn. Due to this damage, the engine wasremoved for further inspection and repair.

An inspection of the right engine cowling icevane door disclosed it was severely cracked in


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the same location as the missing section of theleft door. Also, the “ice vane aft blocker door”(P/N 101-910124-51) was found cracked on boththe left and right cowlings.

The submitter recommended the manufacturermake the “bond assembly” thicker where theactuator brackets are attached.

This recommendation has been forwarded tothe responsible FAA aircraft certificationoffice for action.


Beech Erroneous LandingModel 400A Gear IndicationBeechjet 3260

It was reported the left main landing gear“down” indication was intermittent duringa landing approach.

The problem was traced to the “down” switch(P/N MS24331-1) mounted on the landing gear.It was found that a slight “tap” on the switchproduced a proper indication in the cockpit.The submitter stated this was the third switch

failure on this aircraft in the past 14 months.Another like aircraft in this operator’s fleethad experienced three similar switch failures.In all cases, the landing gear rigging waschecked and was within limits.


CESSNA

Cessna Rudder Spar CracksModel 150 5541Commuter

Cracks were found in the rudder spar whilethe aircraft was being inspected forcompliance with Cessna Service Bulletin (SB)SEB 94-3.

There were three cracks located at the edge ofthe 1 inch hole at the top of the spar(P/N 0433010-6). In accordance with SBSEB 94-3, the rudder spar was replaced. Whenthe replacement spar was received, the 1 inchhole had been omitted from the new part. Alloperators of like aircraft are encouraged toinspect this area and comply with SBSEB 94-3.


Cessna Wheel CracksModel 182P 3246Skylane

While the tires on the right main landing gearwere being changed, cracks were found at eachof the three different bolt holes.

These cracks were located in the center wheelbody section of the three piece wheelassembly. The submitter speculated the causeof these cracks was overtorquing the bolt,during a prior installation, combined withhard landings. It was suggested thatadherence to proper wheel assembly torquevalues during installation might alleviate thistype of damage.



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Cessna Empennage CracksModel P210 5500Centurion

Cracks were found when the antenna, whichwas mounted on top of the tailcone, wasremoved.

A previously installed bulkhead(P/N 1212413-9) repair was discovered duringevaluation of cracks in the tailcone skins(P/N’s 1210504-4 and 1210504-6). This bulkheadrepair and the skin doubler were also foundcracked. The submitter stated this is a poorlocation for an antenna installation due toinadequate structural support for additionalstresses imposed by the extra weight. Thesubmitter also stated the poor quality of theprevious repair may have contributed to thisdefect.

Aircraft total time-6,995 hours.

Cessna Improper FuelModel T210 Injection PumpCenturion Operation

After the Teledyne Continental engine(Model TSIO-520-R) and accessories wereoverhauled, it was reported the fuel pressuredropped when the aircraft was operated above3,500 feet altitude. Also, it was necessary touse the fuel boost pump to maintain adequatefuel flow while climbing above 7,000 feetaltitude.

All attempts at fuel pressure adjustmentproved futile, and when the unmetered fuelpump pressure was increased, the engineoperated in an “excessively rich” condition.After 100 hours of operation andtroubleshooting, the fuel injector pump(P/N 642650-1) was removed and sent to a shopfor a bench test and inspection. Only minordiscrepancies were found, and the pump wasreturned as “serviceable.” The fuel injectorpump was reinstalled, and the operationalflight test disclosed the problem had not beensolved. After another 50 hours of operationand troubleshooting this problem, the fuel

injection pump was again removed and sent toa different shop for analysis. The new shopfound the fuel pump cover (P/N 643950) hadbeen installed 180 degrees out of position. Thiscaused upper deck pressure to the fuel pumpaneroid to be blocked from the passage whichpressurizes the air side of the relief valve(P/N 642644) diaphragm. (Refer to thefollowing illustration.) At the same time, thepassage in the pump cover allowed the air sideof the diaphragm to be exposed only toatmospheric pressure. Decreasing theatmospheric pressure, as the aircraft ascendedon the air side of the diaphragm, could notcompensate for turbocharger boost andresulted in a “self-leaning” fuel mixture to theengine.

Although this problem was caused by theperson assembling the fuel pump having hishead in the “up-and-locked” position, somesafeguard should be incorporated to make thisassembly a bit more “Murphy Proof.” (Ourapologies to all the Murphy’s of the world.No offense intended.)

Part time since overhaul-150 hours.


6

Cessna Pilots SeatModel 310 Adjustment Fitting

Failure2510

Information for this article was submitted bythe FAA’s Aircraft Certification Office(ACE-118) located in Wichita, Kansas.

A Cessna 310R aircraft crashed due to failureof the pilot’s seat adjustment fitting. (Refer tothe following illustration.)

The manufacturer has issued Service BulletinMEB 89-6, Revision 1, dated October 12, 1990,which adds metal straps to the pilot’s seat.These metal straps are intended to reduce theeffects of “mechanical advantage” presented byabuse of the seat. The inspection procedures in(Number 25-10-00) the Cessna 300/400 seriesContinued Airworthiness Program specificallywarn of the possible loss of aircraft control dueto failure of the adjustment fittings(P/N’s 0812735-3 and -4). All operators of theseaircraft are encouraged to comply with theinstructions in Service Bulletin MEB 89-6 assoon as possible.


Cessna Landing GearModel 310Q Torque Tube Failure

3230

The aircraft seemed to be “slower and yawingto the left” during flight. A ground observernotified the pilot that the left main landinggear was extended and the other two wereretracted. The landing gear was selected tothe “down” position, and a safe landing wasmade.

During an investigation, the left main landinggear torque tube (P/N 5045010-19) was crackedat the bolt boss on the fork. This crack hadprogressed in a spiral direction. (Refer to thefollowing illustration.) The rod-endattachment to the torque tube was alsodamaged, and the damage was confirmed by adye-penetrant inspection. Also, the right mainlanding gear was found cracked at the samelocation as confirmed by dye-penetrantinspection. When new parts were orderedfrom the manufacturer (Cessna ServiceKit SK414-8E), the torque tube was noticed toincorporate a gusset at the fork bolt hole, anda larger diameter bolt was used. The submitterspeculated this defect was caused by the highnumber of landing gear cycles and possiblyextending the landing gear at too high anairspeed.

Estimated part total time-5,000 hours.


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Cessna Landing Gear DoorModel 310Q Failure

5280

Just after takeoff, personnel in the controltower informed the pilot that the left mainlanding gear inboard door came open after thegear was retracted. A safe landing was made,and maintenance personnel were summoned.

The landing gear idler bellcrank(P/N 0841106-5) was found broken during aninspection. The bellcrank failed approximately2 inches from the end of the arm whichoperates the gear door extend/retractionlinkage. (Refer to the following illustration.)The failure point on the bellcrank revealedevidence of a previous crack which extendedthrough approximately one-third of itsthickness. It was suspected that improperlanding gear rigging and excessive “doortension,” with the gear down, contributed toand/or caused this failure.


Cessna SpecialModels 401, 401A, Airworthiness401B, 402, 402A, Information Bulletinand 402B (SAIB)

7800

The following article was submitted forpublication by the FAA’s Aircraft CertificationOffice (ACE-112) located in Wichita, Kansas.This article contains the text of Special

Airworthiness Information Bulletin (SAIB)ACE-96-1. (Except for minor editorial changes,this article is published exactly as it wasreceived.)

The purpose of the SAIB is to adviseoperators of the aircraft models listedabove that the Federal AviationAdministration (FAA) is strongly advisingaccomplishing the provisions of CessnaService Letter ME72-4.

As part of the Aging Commuter AirplaneProgram, the FAA has reviewed a numberof existing Airworthiness Directives (AD’s)on airplanes commonly used in scheduledservice. The purpose of the review was toidentify cases where critical repetitiveinspections could be eliminated bymandating installation of improved partsthat do not require such inspections. These“terminating actions” are accomplished byissuance of a superseding AD.

Specifically, an AD supersedingAD 70-03-04, Revision 1, was contemplated.This would have required the installationof steel turbocharger heat shields in placeof the turbocharger insulation blanketsoriginally installed on these airplanes.Currently, AD 70-03-04, Revision 1,requires repetitive inspections of theexisting turbocharger insulation blanketsand acknowledges the installation of thesteel turbocharger heat shield asterminating action for the inspection; butdoes not mandate installation of the steelturbocharger heat shield.

While investigating the feasibility ofsuperseding AD 70-03-04, Revision 1, tomandate installation of the steelturbocharger heat shield, Cessna informedthe FAA that parts to accomplish theproposed terminating action were notavailable and that the tooling required tofabricate the parts was no longer inexistence. It was not deemed feasible tomandate AD action which would requireparts which were not available from themanufacturer. Therefore, it was decided toissue this SAIB. The FAA notes that


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compliance with the repetitive inspectionsmandated by AD 70-03-04, Revision 1,continues to assure safety; but, recognizesthe improvement in safety provided by theelimination of critical repetitiveinspections.

Based on the number of spares sales, it isreasonable to conclude that most of theaffected airplanes have already installedthe steel turbocharger heat shields, andthat there will not be a substantial impacton the fleet.

RECOMMENDATION:

As soon as practical, comply with theprovisions of Cessna Service LetterME72-4. Complying with this ServiceLetter is terminating action forAD 70-03-04, Revision 1. The FAA realizesthat parts are not available from themanufacturer and suggests that utilizingserviceable salvage parts is an acceptablealternative to new parts for thisapplication. The FAA strongly recommendsthat any airplanes not incorporating theprovisions of Cessna Service LetterME72-4 be modified as soon as practical.

Cessna Nose Landing GearModel 402B DamageBusinessliner 3230

During a cross-country preflight inspection,the pilot discovered the nose landing gear forkbolt (P/N 5045211-2) was broken.

The fork bolt was broken at the junction of thethreads and the shank. (Refer to the followingillustration.) Also, the assembly began to pullaway from the bellcrank (P/N 0842104-3). Thelocation of this assembly makes inspectionvery difficult; however, it is worth the extraeffort to avert a possible nose landing gearfailure. Due to the excessively high number ofoperating hours, metal fatigue is the suspectedcause of this defect.


Cessna Deice BootModel 441 MalfunctionConquest 3010

The pilot activated the wing deice system, andthe left wing boots inflated; however, theywould not deflate until the engine was securedafter landing.

An inspection of the system disclosed the leftflow control injector valve (P/N 302353-06)overboard port was obstructed. The port wasplugged with “mud and the egg sacks of aninsect.” Insects, rodents, birds, and othercreatures have caused many aviation problemsin the past. This is a longstanding problem,and the only solution is to completely seal theaircraft in some sort of plastic material whenit is not in use. This, of course, is not practicaland leaves only a thorough inspection prior toflight to discover these types of problemsbefore they cause a hazardous situation. Sincemost insect infestations are seasonal, extracaution should be used during these times. Allinspections should include areas of the aircraftwhich might harbor creatures, their remains,or other material they may deposit.



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GENERAL AVIA COSTRUZIONI

General Avia Costruzioni Broken EngineModel F22B Mount

5346

The student pilot found an engine mountcracked during a preflight inspection.

The crack was located above the nose landinggear strut. When the left side of the enginecowling was opened, another crack was foundbelow the left lower engine mount clusterweld. The submitter recommended themanufacturer construct the engine mount fromheavier material. Frequent inspections of thisarea should be accomplished.


PIPER

Piper Fuel CrossfeedModel PA 23-250 Valve FailureAztec 2823

The aircraft owner reported a strong fuel odorin the cockpit.

An inspection of the fuel system disclosed thefuel crossfeed valve (P/N 492-052) brassreducer fitting was cracked. (Refer to thefollowing illustration.) This fitting had notbeen disturbed for the past 6 years when itsuddenly failed. With the fuel boost pump on,the crack sprayed and atomized fuel in a2-inch fan pattern. The fuel then dripped downon the strobe light power supply creating avery hazardous condition. Since the brassfitting was no longer available from themanufacturer, it was necessary to replace thecomplete crossfeed valve.


Piper Fuel Vent AndModel PA 28-180 Supply HoseCherokee Deterioration

2820

The owner recently acquired this aircraft andremoved the fuel tanks for inspection.

The fuel vent and supply hoses were foundseverely deteriorated. The date stamped oneach of the hoses indicated they were installed


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as original equipment in 1967. The hoses werevery hard and broke under the slightestflexing pressure. Both wing spars wereseverely corroded in the area of the upperoutboard fuel tank. The spar material wasdelaminated for “several inches.” A properexamination of this area during scheduledinspections would surely have eliminated thiscondition and prevented a hazardoussituation.


Piper Low Engine PowerModel PA 28R-200 ProductionArrow 7160

During a preflight engine operational test,engine power could not be advanced beyond1,900 RPM.

The alternate air door was found lodged in thefuel metering unit during an investigation.The door hinge pin (P/N 23809-006) had worncompletely through the attachment door,which allowed the door to migrate into thefuel metering unit. This hinge pin had beeninstalled approximately 1 year prior to thisoccurrence. The aircraft was used in a flightschool environment; however, the alternate airdoor hinge pin should not have failed in thisamount of time. The submitter recommendedthe manufacturer install a tab on the alternateair door which would provide for a “push-pull”test of the hinge. Attaching a “leash” from thedoor to the airframe to prevent ingestion wasalso suggested.


Piper Cracked Wing RibsModel PA 28R-200 5712Arrow

During a scheduled inspection, wing ribs werefound cracked in the wing walk area of theright wing.

Three ribs were cracked at the outboard edge.The submitter suspected the damage wascaused by high operating time and possibly the

stress which was induced when ribs wereformed. It was stated: “This seems to be acommon occurrence on this make and model ofaircraft with over 4,000 hours.” This areadeserves close attention during inspectionsand maintenance.


Piper Foreign ObjectModel PA 31-325 Damage (FOD)Navajo 2140

The pilot reported that when the defrosterwas started, grass and other debris blew out ofthe vents.

An inspection disclosed a bird’s nest had beenbuilt in the heater, and grass was found in theheater inlet, the blower fan, and inside theheater around the burner can. The submittersuggested the manufacturer authorize theinstallation of an inlet screen on the heater.A thorough preflight inspection could havedetected this FOD prior to starting thedefroster.


Piper Rudder ControlModel PA 32-260 FailureCherokee Six 2721

The pilot reported experiencing excessiveright rudder application with very littlecontrol response during flight.

An inspection revealed the rudder control barassembly (P/N 63420-02) was severely crackedat the left weld area of the cross-over bar. Thesubmitter speculated this defect was caused byexceeding the towing limits groundpositioning of the aircraft. Also, a lack oflubrication between the rotating bars mayhave been a contributing factor. Periodiclubrication, inspection of the weld areas, andadherence to the towing limits were suggestedto avert recurrence of this defect.



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Piper Nose Landing GearModel PA 34-200T Steering ShaftSeneca Failure

3250

The nose landing gear center shaft of thecentering spring assembly (P/N 96522-00) wasfound sheared during a scheduled inspection.

The shaft failed at the rod-end attachmentthreaded area. (Refer to the followingillustration.) A visual inspection of the brokenshaft indicated it had been partially cracked ina vertical direction for some time prior tocomplete failure. It was suspected this damagewas caused by exceeding the turning limits(while towing the aircraft). Frequentinspection of this area and adherence to thespecified turning limits while towing wererecommended.


Piper Broken FlightModel PA 38-112 Control PulleyTomahawk Brackets

2700

Excessive play was found in the elevatorcontrol system during an annual inspection.

An investigation disclosed that both “gangpulley brackets” (P/N’s 77844-02 and 77844-03)were broken. The brackets, located atFuselage Station 134, were used toaccommodate five sets of flight control pulleys.The brackets were broken at the point wherethe center bolt passed through one bracket,then through the five pulleys, and thenthrough the other bracket. The submitter didnot offer a cause for this defect. Consideringthe high number of operating hours, it seemslikely that metal fatigue may have been animportant factor in this failure. This areashould be checked by dye-penetrant inspectionmethods during all scheduled inspections.


Piper Broken EngineModel PA 42-720 Mount BoltCheyenne 5346

The left engine upper outboard engine mountretention bolt (P/N 553-344) was found brokenduring a scheduled inspection. These bolts areused to attach the engine mount to thefirewall.

The manufacturer has established a life limitfor these bolts of 7,500 hours of operation. Theset of engine mount retention bolts installedon this aircraft had accumulated 5,338 hours ofoperation. After finding this bolt broken, adecision was made to replace all of the enginemount retention bolts. The bolts were removedand sent to a metallurgical laboratory forfracture analysis. The laboratory report statedthe crack, which resulted in a completefracture, was the result of stress corrosioncracking (hydrogen embrittlement). The reportalso noted the clamping load had beenreduced, and the bolt torque was equal to orless than the clamping friction force (it shouldalways be greater in a properly clamped


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structure). The submitter suggested thesebolts be replaced during each engine changealong with the application of corrosionpreventive compound. Also, it was suggestedthe running friction torque of the bolt beadded to the specified torque value to ensureproper clamping force; however, this shouldnot be done until the manufacturer revises thetechnical data to include this process. Thesesuggestions, along with this report, have beensent to the responsible FAA aircraftcertification office for action.

Part total time as previously stated.

Piper Fuselage NoseModel PA 44-180 Section Spar CracksSeminole 5313

Both of the nose cone spars were founddamaged during a 100-hour inspection.

The spars (P/N’s 86444-800 and 86444-802) hadcracks in the “L-angle” reinforcement. Thisreinforcement is used to attach the noselanding gear drag link mounting bracket to thefuselage. The cracks were located at the loweraft bolt hole for this mounting bracket. Thecracks ran lengthwise and extended past thebolt holes approximately 1 inch in eachdirection. The submitter stated this was thesecond like aircraft found with this defect. Thelocation of this area makes inspection verydifficult; however, the submitter suggestedevery effort be made to conduct a properinspection.


SABRELINER

Sabreliner Suspect WindowsModels 265-40, -60, 5620and -65

Information for this article was furnished byMr. Richard Brooks of the FAA ManufacturingInspection District Office (ACE-180) located inKansas City, Missouri.

It has been reported that in some instances,windows on these aircraft have been replaced

with “military surplus windows (inner, outer)”released by the Department of Defense.

Windows (P/N’s 265-318207-002 inner and265-318205-012) for the right assembly(P/N 265-318002-902), and (P/N’s 265-31207-001inner and 265-318205-011 outer) for the leftassembly (P/N 265-318002-901) are used onthese models. Repair stations may bereplacing the individual inner and outerwindow panels without using the properfixture and assembly procedures. The airframewhich holds the window assembly is notadequate to be used as a holding fixture duringassembly of the window panels. The properfixture and procedure should be used toprevent cracking of the window panels. Themanufacturer has not made this equipment orprocedure available and sells each unit as anassembly. It is recommended that thesewindows be replaced as assemblies using theassembly part numbers previously given.

Part total time not applicable.

STINSON

Stinson Wing Spar CorrosionModel 108-3 5711Voyager

The left wingtip was damaged during a suddenwindstorm. While repairing this damage, thewingtip bow was removed, revealing severecorrosion on both spars (P/N’s 1112146-0and 1112147-0).

While in search of “hidden damage,” the leftwing fuel tank was removed, and even moresevere intergranular corrosion was detected.The left wing forward spar had beenpenetrated by the corrosion just outboard ofthe lower fuselage attachment lug. Thecorrosion hole was approximately 2 inches indiameter. After removal of part of the wingskin, a section of the spar (approximately 2feet long) was found severely corroded. It hadprogressed to the point of almost completedisintegration of the spar center section at thedrag brace wire attachment point. At the timeof this report, the submitter had made only acursory inspection of the right wing.


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The results of that inspection were similar,but less severe. The submitter speculated thecause of this corrosion was age and thepresence of a “large bird’s nest” in the leftwing. This aircraft was manufactured in 1948.


HELICOPTERS

BELL

Bell Tail Rotor YokeModel 206BIII CrackJet Ranger 6400

During a daily cleaning of the helicopter, thepilot noticed what appeared to be a crack inthe tail rotor yoke (P/N 206-011-811-009).

After removing the paint from the suspectarea, a crack was confirmed visually by using amagnifying glass. It appeared the crackoriginated at the center line of the yokeoutboard bolt hole and extended to the outerend of the yoke. The crack had begun to travelto the other side of the yoke. Any abnormalityof the paint in this area should be thoroughlyinvestigated.

Part total time since overhaul-1,233 hours.

Bell Skid Tube CracksModel 206L1 3270Long Ranger

A skid tube was found cracked during ascheduled inspection. This finding promptedan inspection of the skid tube(P/N 206-324-003) on the opposite side, wheresevere corrosion damage was discovered. (Nocracks were found on this skid tube.)

Both of the skid tubes had been installed 27months prior to this discovery. The cracksappeared to originate at the steel inserts.(Refer to the following illustration.) It wasspeculated that improper installation or holepreparation for the inserts may have inducedstress which caused the cracks. These skid

tubes had been installed under aSupplemental Type Certificate (STC) and weremanufactured under a Parts ManufacturingApproval (PMA). Both skid tubes were primed,painted, and ready for installation whenreceived, and this included installation of theskid shoes.


Bell Updated Tail RotorModels As Feathering BearingGiven Below 6400

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

Bell Helicopter Textron has issuedTechnical Bulletin Number(TB) 206L-94-172, dated December 19, 1994.This TB introduces an improved tail rotorblade feathering bearing(P/N 206-310-105-101) to replace the oldfeathering bearing (P/N 206-010-765-001).The aircraft models and serial numbersaffected are as follows:

206L, S/N 45004 through 45153, and 46601through 46617

206L-1, S/N 45154 through 45790

206L-3, S/N 51001 through 51612

206L-4, S/N 52001 through 52104

Model 206L-4, S/N 52105 and subsequentwill have tail rotor blades(P/N 206-016-201-131) and yoke


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(P/N 206-011-819-109) installed prior todelivery.

Tail rotor blade (P/N 206-016-201-131)incorporates feathering bearing(P/N 206-310-105-101). Tail rotor blade(P/N 206-016-201-131) is the sparereplacement for tail rotor blade(P/N 206-016-201-127).

Part (I) of this TB provides modificationinstructions to retrofit bearing(P/N 206-310-105-101) to existing tail rotorblades (P/N’s 206-016-201-001, -107, -113,and -127).

Feathering bearing (P/N 206-310-105-101) isreduced in cross-section and requires anew tail rotor yoke assembly(P/N 206-011-810-109) with thicker flangebushings (P/N 206-011-816-105). Tail rotoryoke (P/N 206-011-819-109) is the sparereplacement for tail rotor yoke(P/N 206-011-819-105).

Part (II) of this TB provides modificationinstructions to retrofit bushing(P/N 206-011-816-105) to existing tail rotoryoke (P/N’s 206-011-819-101 and -105).

Part (III) of this TB provides configurationand installation instructions for a new ormodified tail rotor blade assembly and newor modified tail rotor yoke assembly.

For more specific information consult theTB or the manufacturer.

MCDONNELL DOUGLAS

McDonnell Douglas Defective MainModel 369D Rotor Transmission

Drain Plug6330

The main rotor transmission drain plug wasfound cracked during overhaul.

The plug (P/N B3148A) was cracked in theradius at the junction of the head and the plug

barrel. (Refer to the following illustration.)The crack traveled around the entirecircumference; however, it had not penetratedthe wall thickness of the plug barrel.The submitter did not offer a cause for thisdefect; however, it seems likely that excessivetorque may have been a factor.

McDonnell Douglas Tail Rotor PinionModel 369D Shaft Damage

6400

The main rotor transmission and the tail rotoroutput pinion shaft were found damagedduring an overhaul and inspection.

It was determined the damage had beencaused by a broken bearing race. The outputpinion shaft (P/N 369025125-13) was severelygouged at the bearing land and retaining ringlip. (Refer to the following illustration.)The shaft was replaced due to gouges andnicks. This area should be closely checked atevery opportunity.



15

AMATEUR, EXPERIMENTAL, ANDSPORT AIRCRAFT

EDGE

Edge Ignition HarnessModel 540 Defect(Poe G.L., S.Y.) 7400Engine Textron LycomingModel IO 540

Although this problem occurred on anexperimental aerobatic aircraft, it could alsooccur on any aircraft using this engine/ignitionharness combination.

The ignition harness spark plug nut was foundseized to the drive ferrule making removalfrom the spark plug impossible. It appearedthe spark plug nut was too heavily “plated.”This resulted in “galling” of the nut and thedrive ferrule during installation. The “plating”also formed slivers of metal which were foundin the spark plug ceramic. This drive ferrulewas coated with “antiseize compound,” andoperation returned to normal.


HOT AIR BALLOONS

HEAD

Head Suspension CableModel AX8-88 Serving Defect

5102

The serving around the Kevlar suspensioncable was found loose during a scheduledinspection.

The Kevlar suspension cable is sewn togetherand further secured by a serving (nylon cordwrap). The serving is used to maintain an“eye” at the base of the cable. (Refer to thefollowing illustration.) The submitter stated:“This part was unairworthy.”

The manufacturer’s maintenance manual doesnot include a repair for this defect.


PROPELLERS ANDPOWERPLANTS

TELEDYNE CONTINENTAL

Teledyne Continental Defective FuelModel 421B InjectorGolden Eagle 7313

Fuel stains were noticed on the Number 3cylinder while accomplishing a repair insidethe right engine cowling.

The fuel stains were adjacent to the threadedportion of the fuel injector. The injector(P/N 633723D19A) broke at the threads when


16

it was being removed. Further inspectionrevealed the orifice in the outlet end of theinjector was drilled “off center.” (Refer to thefollowing illustration.) Failure to have aninjector in this area would allow raw fuel to beexpelled and present a potentially hazardouscondition. The submitter suggested thatinjectors be closely inspected for this conditionat every opportunity.

Part time since overhaul-846 hours.

ACCESSORIES

DEFECTIVE AVIATION HOSES

The following article was submitted by theFAA Aircraft Certification Office (ACE-118)located in Wichita, Kansas. (Except for minoreditorial changes, this article is publishedexactly as it was received.)

Defective MIL-H-6000 hose,.5 inch to 3 inches inside diameter, hasbeen found installed in fuel and fuel ventsystems.

The inner liner has delaminated andseverely restricted fuel flow. The hose,

manufactured by Buckeye RubberProducts, Inc., is of a spiral wrappedconstruction with a .375-inch wide redstripe and the number 94519 may bevisible. (Refer to the following illustration.)Defective hoses have been found with thefollowing quarterly manufacturing datemarkings: 2Q94, 1Q95, 2Q95, and 3Q95.Also, hoses with other manufacturing datemarkings may be suspect.

All maintenance technicians should bealert for the presence of these hoses, eitherinstalled on an aircraft or new from a partsdistributor.

AIR NOTES

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 access


17

this 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 filenames 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 25082Oklahoma 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.


18

A TRIBUTE TO THE FORGOTTENMECHANIC

Through the history of world aviationmany names have come to the fore.

Great deeds of the past in our memorywill last, as they’re joined by more andmore.

When man first started his labor in hisquest to conquer the sky he wasdesigner, mechanic, and pilot, and hebuilt a machine that would fly butsomehow the order got twisted, andthen in the public’s eye the only manthat could be seen was the man whoknew how to fly.

The pilot was everyone’s hero, he wasbrave, he was bold, he was grand, as hestood by his battered old biplane withhis goggles and helmet in hand.

To be sure these pilots all earned it, tofly you have to have guts.

And they blazed their names in the hallof fame on wings with bailing wirestruts.

But for each of these flying heroes therewere thousands of little renown, andthese were the men who worked on theplanes but kept their feet on theground.

We all know the name of Lindbergh,and we’ve read of his flight to fame.

But think, if you can, of hismaintenance man, can you rememberhis name?

And think of our wartime heroes,Gabreski, Jabara, and Scott.

Can you tell me the names of their crewchiefs?

A thousand to one you cannot.

Now pilots are highly trained people,and wings are not easily won.

But without the work of themaintenance man our pilots wouldmarch with a gun.

So when you see mighty aircraft as theymark their way through the air, the“grease-stained man” with the wrenchin his hand is the man who put themthere.

The anonymous author of this compositionmust surely have had an appreciation andrespect for those of us past and present whoendeavor to promote aviation safety to thehighest possible level. We endure theenvironmental extremes of the flightline andare content to allow those who are pilots toreap the glory of the public eye. We arecontent to remain in the background with thecalm assurance that we have given our all inthe pursuit of safety in aviation. We swell withpride as we watch the product of our labor risegracefully from the runway and embrace apristine sky.

The greatest and most valued recognition wecan hope to receive comes from our peers andfrom within. The Aviation Awards Programhas become one of the most coveted forms ofrecognition for maintenance personnel.This program stresses education, training, andsuperior performance, as well as the otherattributes mentioned here, to praise thoseworthy of its tests. Our most valued assets arethe tools of our trade, our reputation andintegrity, and the respect of our customerswho put their lives in our hands.

With the many technological and sociologicaladvances in aviation over the years, many ofthe ideas put forth in this poem are no longervalid. “Bailing wire” for example, is very muchfrowned upon as wing strut and hinge pinmaterial.


19

Maintenance personnel, for the most part, nolonger fit the stereotype “grease-stained man,”which has been distorted and propagated bythe entertainment media. The “grease-stainedman” with a rag hanging from his pocket, capwith a turned up bill, and a less thanintelligent look on his face, is purely a fictionalcharacter created to provide contrast andfurther embellish the flyer. Also, not allmaintenance men are men; there are manywomen now who have earned a position amongthe ranks and have made significantcontributions to aviation maintenance safety.

Through the evolution of aviationmaintenance, the requirements of brawn hasbeen replaced by an ever-expandingrequirement for brain power. With thecomplex nature of today’s aeronauticalproducts has come maintenance people whocan analyze, forecast, and troubleshootproblems by use of the computer. (Usually, wedo not get “grease-stained” from this activity.)The ever-changing demands of maintainingtoday’s aircraft present a new challenge eachday which is met with an eager enthusiasm tolearn something new and to put things right.We approach each new challenge with prideand a confident demeanor which seems to say:“You can’t break anything that I can’t fix!”

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.

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.

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

U.S.Departmentof Transportation

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