Screwed by a Nut

RV fuel pickups may be rotated by turning a nut just like youre supposed to


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


A Vans RV-8 made a forced landing after losing engine power immediately after takeoff.

The accident investigation showed the fuel tank had 10 gallons in it, but the fuel pick-up tube was crimped just outboard of its threaded fitting, and the tube had rotated more than 180 degrees.

This resulted in the pick-up intake end of the pick-up tube being positioned midway between the top and bottom of the tank.

The pilot/builder reported that several weeks previous to the event, he had accomplished maintenance on the right fuel tank and had tightened the nut that secured the fuel pick-up tube 90-degree elbow fitting to the right fuel tank access plate.

The aircraft design drawings revealed that tightening the nut that secures the 90-degree elbow fitting tight against the access plate may rotate the elbow and thus inadvertently deform and reposition the fuel pickup tube.

American Champion 8KCAB Decathlon
Aileron Control System Restriction

While performing aerobatic maneuvers, the pilot rolled right, at which point the aileron control jammed. He used all his force on the aileron control and full left rudder input, and the aircraft entered a steep slip. After a few seconds, he felt a pop and regained control of the aircraft. He made an immediate and safe landing.While inspecting the aircraft, a technician found a pin-and-ring assembly, which he identified as the emergency door release pin, loose on the bottom skin just below and aft of the right lower aileron bellcrank. He also found a freshly-made impression on the emergency door release pin.

Beech A36TC Bonanza
Electrical System Failure

While the pilot was completing the pre-takeoff checklist, the aircraft suffered an electrical system failure.A technician discovered the aircraft battery was smoking, but none of the circuit breakers, fuses or current limiters had popped. Each battery cell was almost dry. In addition, an electrical short circuit had been made between the positive battery cable and the throttle cable. The throttle cable had chafed against the battery cable and penetrated the cable insulation, which caused a direct electrical short between the batterys positive cable and ground.

Beech 58 Baron
Autopilot Pitch Servo Failure

The pilot reported the autopilot pitch axis failed after flying through turbulence. The pitch servo remained engaged; however, it would not follow the flight director. When the technician removed the unit, he noted the sound of loose internal parts and returned the Bendix-King unit to the manufacturer as required by the warranty.Part total time – 149 hours.

Beech C90A King Air
Engine Exhaust System Crack

During an engine inspection, the technician discovered a crack in the exhaust system.The right engine inboard exhaust stack displayed a 1.5-inch crack adjacent to a weld at the nacelle inlet deice tube attachment point. This was the sixth reported occurrence of this defect on the same aircraft. The technician discussed the problem with the manufacturer and a service bulletin release is pending.Part total time – 21 hours.

Cessna 172L Skyhawk
Defective Fuel Selector Valve

Maintenance personnel installed a new fuel selector valve in accordance with the manufacturers technical data and conducted extensive leak and operational tests.The tests included fuel flow to the carburetor at each of the three selector valve positions. All tests proved satisfactory and the technician returned the aircraft to service. After approximately 2.5 hours of flight time, the engine failed due to fuel starvation. The pilot landed safely at a nearby airport.The pilot had run the right tank dry and the left tank was still full. A technician investigated and discovered the selector valve was not allowing fuel flow from the left tank with the valve in the both position. Fuel flow was normal in all other selector valve positions.The fuel starvation incident occurred when the right fuel tank was empty with the fuel selector being in the both position. The fuel remaining in the left tank could not flow past the selector valve.Part total time – 2.5 hours.

Cessna R182 Skylane RG
Defective Rudder Pedal Security

A technician submitted reports on five different aircraft with identical defects. All of these aircraft had approximately 10,000 hours operating time. The FAA Service Difficulty Program database contains one additional report that is similar.During an annual inspection, he discovered cracks in the inboard rudder pedal bar bearing block brackets. In order to inspect the area, he moved the rudder pedals and noticed the bearing blocks flexed. After he cleaned the area, he discovered the cracks on the left and right bracket assemblies.

Cessna 182S Skylane
Autopilot Roll Servo Defect

While complying with Bendix/King SB KS271C-5, the maintenance technician discovered problems with the autopilot roll servo assembly unrelated to the SB.The roll servo idler gear attachment nut had backed off the threads. The output gear bearings were contaminated with dirt and metal shavings from an unknown origin. Part total time – 143 hours.

Lake LA-250
Elevator Horn Cracks

While completing an annual inspection, the technician found the elevator horn attachment brackets broken.The breaks appeared in the upper ears of both attachment brackets, possibly caused by metal fatigue. Part total time – 1,900 hours.

Piper PA-23-250 Aztec
Main Landing Gear Retraction Defect

During an annual inspection, the technician discovered the left main landing gear would not fully retract into the wheel well.A gap of approximately 1.5 inches remained between the gear doors at the completion of the retraction cycle. The technician investigated and found a section of the actuating cylinder rod broken out of the threaded end and the end cap severely damaged.

Piper PA-28-140 Cherokee
Main Landing Gear Strut Cracks

After a flight, the student pilot reported experiencing shimmy and vibration during the landing rollout.A maintenance technician found the left main gear strut attachment ears for the upper torque link broken. The broken ears left the wheel assembly free to rotate, restrained only by the brake line. Side loads imposed on the gear during landing might have caused this damage. The FAA Service Difficulty Program data base contains 11 additional reports concerning similar failures. Piper Service Letter 760 deals with this subject.Part total time – 7,354 hours.

Piper PA-28-181 Archer
Defective Starter Armature

A technician reported finding six Electrosystem starter armatures with the drive end spline worn or stripped away.The metal debris produced by the spline removal contaminates the gear case, causing damage to the roller bearings. The submitter reported the drive gear did not display damage, and the shear pin remained intact in all cases.Part total time – 839 hours.

Piper PA-28R-201 Arrow
Main Landing Gear Crack

During a scheduled inspection, the technician discovered a hydraulic leak in the left main landing gear area.After further investigation, he discovered a crack in the landing gear trunnion at the point where the web joins the trunnion tube. This is a typical area for crack development, especially on high-time components used in a training environment.Part total time – 9,165 hours.

Piper PA-28R-201 Arrow
Defective Wing Attachment Bolts

As part of a wing repair process, the submitter removed the wing attachment bolts.All the bolts displayed severe corrosion and required replacement. This was the third occurrence of this defect found by the submitter during a six-month period.Part total time – 3,273 hours.

Piper PA-31-350 Chieftain
Numerous Magneto Problems

This aircraft is equipped with Textron Lycoming Model TIO-540 and LTIO-540 engines using Bendix dual magnetos.According to the aircraft maintenance records, this aircraft experienced numerous and recurring problems which included unusual drop-off, completely dead magneto, hard engine starting, and the engine failing to start. The records attributed all these defects to faulty capacitors. TCM SB 662A lists capacitors coded prior to 9946 that should have been removed from service and replaced with newer code-number capacitors. After complying with SB 662A, engine operation has been satisfactory for this operator.

Piper PA-32R-301 Saratoga
Main Landing Gear Cracks

During an annual inspection, a technician found cracks in both of the main landing gear strut assemblies.Using a magnifying glass, the technician discovered cracks adjacent to the two top axle bolt holes on both the left and right strut assemblies. These six holes attach the wheel brake anchor plate to the strut. The metal is thinnest at this location. The aircraft maintenance records did not include any damage history or hard landings. The FAA Service Difficulty Reporting program data base contains five other similar defects.Part total time – 3,351 hours.

Piper PA-39 Twin Comanche
Wing Structural Damage

The pilot reported experiencing an unusual vibration during flight. He also noticed the right wing tip tank trailing edge fluttering approximately 1 inch. The pilot reduced power and made a safe, precautionary landing.A technician discovered a crack extending through the lower spar cap and approximately 1 inch up into the face of the aft wing spar. Several solid rivets, originally used to attach the upper wing skin to the rib and aft spar at WS 132, had been replaced with cherry type rivets during previous maintenance.The technician reviewed the aircraft maintenance records which stated the aircraft experienced a hard landing 2 years prior. At that time, a technician made repairs that included replacing the right main landing gear and repair of the aft tail bulkhead.Aircraft total time – 3,376 hours.


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