Shrinking Gaskets

The following information is derived from the FAA’s Service Difficulty Reports and Aviation Maintenance Alerts

Friday, March 15, 2013 at 12:00 AM ET

Verified

The crew for the planned mission, Robert Behnken (left) and Douglas Hurley, had made a practice run in January for the flight test in May. SpaceX

Key Takeaways:

Multiple aircraft experienced landing gear system malfunctions, including uncommanded retraction/extension and gear collapse, often due to faulty switches, corrosion, or actuator failures.
Various engine components also failed or malfunctioned, such as shrinking rocker box gaskets causing oil leaks, rough starter adapter bearings, and magneto points assembly defects leading to poor engine performance.

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Beech C90GT King Air
Malfunctioning Gear Switch
After takeoff, the landing gear retracted with the landing gear control switch in the down-and-locked position. The landing gear retracted uncommanded as soon as the aircraft achieved a weight-off-wheels configuration during the takeoff roll.
Part Total Time: 1023 hours

Piper PA-28RT-201 Arrow IV
Corroded MLG Downlock Switch
During landing gear extension, the right main landing gear light flickered. The gear appeared down to observers. During the landing rollout, the right main landing gear collapsed. Inspection revealed corrosion and lack of lubrication. The right gear-down limit switch was rigged to the full-up position, possibly making contact with right downlock hook prematurely.
Part Total Time: 9114 hours

Piper PA-44-180 Seminole
Failed Nose Gear Actuator
After takeoff, landing gear was retracted. Immediately after gear-up indication, a gear warning was indicated. After landing it was found that the rod end (p/n 452729) bearing in the nose gear actuator had broken, allowing the nose gear to extend and return to a down-and-locked position.
Part Total Time 7541 hours

TCM IO-550-C
Shrinking Rocker Box Gaskets
What was described as a “major oil leak” was traced to the engine’s rocker box cover gaskets. Five of the six gaskets (p/n 655528) shrank between the bolts, causing leakage.
Part Total Time: 171 hours

TCM IO-550-N
Failed Starter Adapter
When turning the prop during a compression test, the technician noticed a clunking and ticking noise, which was traced to the starter adapter in the Cirrus SR22. Removed adapter and found the bearing on the drive shaft that goes into the engine is very rough and jerky. This is the second occurrence of this issue on two different aircraft, both with very low time on their starter adapters (p/n 642085A17).
Part Total Time: 60 hours

Slick 6320 Magneto
Failed Points Assembly
The engine, installed in a Lancair IV-P Experimental, began to run poorly. On inspection, the left magneto was found inoperative. The magneto was removed, disassembled and inspected. The follower arm had separated and was laying in the top of the magneto. The right magneto was removed for inspection, and corrosion was seen on the follower arm in the area where the stiffener section stops.
Part Total Time: 176 hours