Inspect Yer Gadgets

Sloppy inspections allow minor problems to progress into big ones


The following information is derived from the FAAs Service Difficulty Reports and Aviation Maintenance Alerts. Click here to view “Airworthiness Directives.”


American General AA-5A Cheetah
Poor Engine Performance

The aircraft owner reported the engine performance deteriorated during flight.A mechanic discovered the carburetor bowl was not attached tightly to the throttle body. Even though the locking-tab washers under the attachment screws were properly installed, the screws were loose. The gasket may have shrunk or the attachment screws were not properly tightened during installation, allowing excessive air to be drawn into the carburetor.

Beech V35A Bonanza
Flight Instrument Failure

The pilot reported that the gyro instruments failed shortly after takeoff. This aircraft uses a pressurized instrument air system that is plumbed through the instruments and exhausts through a -inch plastic tube. The tube is routed through a grommet in the aft wall of the nose gear wheel well and terminates at a point adjacent to the nose gear tire when the tire is retracted. The mechanic determined the tube had migrated into the wheel well far enough to be obstructed by the nose gear tire.

Beech 58 Baron
Landing Gear Position Indication

During a landing approach, the pilot noticed the nose gear down-and-locked light did not illuminate when he placed the gear lever in the down position. The pilot landed the aircraft safely.A technician discovered that the fork-end of the plunger assembly, located on the gear retraction rod assembly, was broken. The broken fork on the plunger assembly produced the erroneous position indication.

Beech 58P Baron
Landing Gear Failure

While taxiing, the nose landing gear collapsed, followed by the collapse of the right main gear.An airworthiness inspector noted that the landing gear gearbox was in the full-down position and the nose gear retraction arm was broken.He surmised that when the nose gear retraction arm failed, it released the overcenter tension on the nose gear down-lock and the gear retracted. Failure of the nose gear apparently induced a side load on the right main gear, bending the retraction arm assembly enough to allow the gear to collapse on the closed inner gear door.

Beech 200 King Air
Seat Track Corrosion Damage

A technician searching for the source of a strong mildew odor found the carpet and furnishings in the drip area of the cockpit windows severely deteriorated and the seat track rails corroded to a nonrepairable state. The screws used to secure the seat track rails to the structure had almost disintegrated from the effects of corrosion. Part total time – 2,203 hours.

Cessna 172M Skyhawk
Poor Engine Performance

During a scheduled inspection, the maintenance technician discovered the screws used to secure the carburetor bowl to the throttle body were loose. He found the screw locking tabs in place and properly installed.The technician removed the carburetor and did not find any other defects. The condition may have been caused by gasket shrinkage and/or undertorque of the fasteners during installation.Part time since overhaul – 1,320 hours.

Cessna 172R Skyhawk
Rudder Control Defect

Pilots reported the rudder control did not feel right and the mechanic discovered the left rudder pedal return spring had broken at the rudder pedal attachment point.The mechanic said this was the second time he had seen the problem in a fleet of four like aircraft. The cause of the defect was uncertain, but its possible the spring material had not received proper heat treatment.Part total time – 1,509 hours.

Cessna 172S Skyhawk
Fuel Shut-Off Control Failure

During a preflight inspection, the pilot moved the fuel shut-off control out of the off position. The control remained in the off position, and the cable came out of the housing.The cable had been clamped tightly against the fuel shut-off valve lever and it could not move freely when the pilot activated the control. It appeared that the cable bent back and forth with the control until the metal cable became work-hardened and broke.Part total time – 263 hours.

Cessna 550 Citation
Wheel Brake Failure

The pilot stopped on the taxiway and the airplane would not move when the flight was cleared to take off. A mechanic found a cracked right wheel brake inboard stator. The stator cracked across its width, and the crack opened enough to allow the stators cracked edge to catch on a wheel-drive key. Part total time – 445 hours.

Mooney M20D
Landing Gear Control Failure

While taxiing at approximately 5 mph, all three landing gear collapsed. The landing gear control was in the down position, and the green light indicated the gear was down and locked.An investigation revealed the landing gear retraction handle, or Johnson bar, broke at the point where it attaches to the bellcrank arm below the cockpit floor.

Mooney M20K
Aileron Trim System Binding

The owner complained that the aileron trim system was very stiff to operate manually.The mechanic discovered that the bearing assembly was frozen. Although the technician decided not to use the bearing assembly again, he cleaned and lubricated the old unit and it rotated freely, implying that the unit should be regularly lubricated.Part total time – 1,532 hours.

PZL 150A Koliber
Nose Landing Gear Failure

After landing the nose gear began to shimmy violently, the axle broke and the wheel assembly separated from the aircraft.The nosewheel axle is hollow at the point where it broke. The failure appeared to be the result of a pre-existing crack. Maintenance records showed the nose gear axle had been replaced four years earlier.Part total time – 376 hours.

Piper PA-28-140 Cherokee
Defective Engine Oil Filter

During an annual inspection, the technician changed the oil and filter. An engine operation test revealed an oil leak, which was attributed to the newly installed Champion filter. Another new oil filter was installed and again leaked when tested. The old filter was reinstalled and did not leak when tested.The technician determined the new oil filter threads bottomed out before the sealing surfaces were properly mated. Champion investigated and determined that the filters used the maximum thread length allowed by the specifications. The extra stud length was minimal. The oil filter adapter thread length was in the mid range of the drawing limits. The combination of these factors was sufficient to prevent proper sealing of the gasket.

Piper PA-28-161 Cadet
In-Flight Engine Failure

The engine failed just after takeoff during an instructional flight.A technician found that the gascolator drain valve was stuck in the open position. The drain valve displayed signs of varnishing and was very stiff and binding.

Piper PA-28R-200 Arrow
Defective Engine Mount Tubes

During other maintenance, the technician noticed cracks at the base of the two vertical engine mount support tubes adjacent to the weld joining them to the engine mount assembly. He removed the engine, conducted a dye penetrant inspection, and discovered that the tubes were completely broken around the circumference of their respective welds. These defects were not visible initially because they were hidden by paint.The cracks may have stemmed from hard landings and the use of the aircraft for flight training. There was also the possibility that the support tubes had been improperly repaired previously. The maintenance records did not show a previous repair, but the technician knew of a prior landing gear collapse incident.

Piper PA-32R-300 Lance
Engine Oil Leak

After landing, following a 4-hour overwater flight, the pilot noticed engine oil dripping from the left side of the aircraft.The leak was traced to a crack in the oil cooler installed as part of STC SA3736WE, which is primarily a cowling modification. The oil cooler was made by Niagara and the STC owner and oil cooler distributor was Lopresti Speed Merchants.The oil cooler cracked at the base of the top cooling fin just below the hose fitting base.Part total time – 463 hours.

Piper PA-32R-301T Turbo Saratoga
Defective Fuel Quantity System

The pilot reported the right fuel gauge operated erratically. The mechanic replaced the right sending units but could not calibrate the system because the gauge indicated 10 gallons when the tank was empty. The technician discovered that the inboard sending unit float arm was getting caught on a cutout in the rib.

Piper PA-44-180 Seminole
Defective Engine Mount

During a scheduled inspection, the technician discovered a broken engine mount.The right engine mount was broken at the top left, just below the Lord mount. The left engine showed the same defect. Several factors may have contributed to this defect, including age, hard landings, environmental operating conditions and exposure to corrosive elements. Part total time – 4,913 hours.

Teledyne Continental TSIO 360
Piston Failure

The engine, installed in a Mooney M20K, lost power during climb, resulting in an off-airport landing.A mechanic discovered the No. 1 cylinder was broken and separated approximately two inches above the base. The piston was broken through the piston pin bore and the upper portion of the piston remained in the cylinder while the lower portion was disintegrated by the internal engine moving parts. The engine had attained the TBO published by the manufacturer.Engine total time – 1,800 hours.


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