Cracked, Failed, Broken

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

Wednesday, December 19, 2012 at 12:00 AM ET

Verified

Key Takeaways:

Reports detail diverse component failures across various aircraft systems, including electrical switches, engine parts (crankshafts, exhaust, TIT probes), and nosewheel steering.
Failure causes varied from material fatigue (cracked crankshaft/exhaust), manufacturing defects (broken solder joint), and premature part breakdown (TIT probe after 21 hours, magneto after 16 hours) to inadequate maintenance (lack of grease).
The incidents underscore the importance of diligent maintenance practices, adherence to Airworthiness Directives, and utilizing improved part designs to prevent recurring failures.

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Beechcraft A36 Bonanza
Failed Strobe Light Switch
During a routine inspection, it was noted the strobe lights would remain on after the switch was selected “off.” Troubleshooting revealed the switch to be defective. Once replaced per AD 2008-13-17, the original switch was disassembled. The solder joint holding the braided wire had broken, and welded itself to the line post. Switch p/n 35-380132-103.
Part Total Time: 516.0 hours

Beechcraft C90GTX King Air
Failed Nosewheel Steering
The aircraft’s nosewheel steering failed. Investigation revealed lack of grease on the steering brace (p/n 101-820024-15). No other findings or problems were detected on the steering assembly. After greasing, operational and functional tests performed smoothly. Recommendation: The steering brace must be greased with the aircraft both on and off jacks to guarantee full lubrication.
Part Total Time: (unknown)

Continental IO-520-C
Cracked Crankshaft
The crankshaft (p/n: 649859) cracked in the propeller flange at the radius. The crack (appeared) in a “V” shape. On one side, the crack was about four inches long and about three inches on the other.
Part Total Time: 1397.0 hours

Continental IO-550-N

Cracked Exhaust
The Cirrus SR22 was equipped with a Tornado Alley Turbo normalizing system. During an unrelated inspection, the right tail pipe was found cracked completely in half along the forward edge of the cabin heat exchanger weldment. An improved designed tail pipe is available from Tornado Alley, and the submitter recommends against welding cracked tail pipes in favor of replacement with the new design.
Part Total Time: 678.0 hours

Lycoming TIO-540-AE2A
Broken TIT Probe
While troubleshooting a “No TIT” indication on the engine in a Piper PA-46-350P Malibu Mirage, the turbine inlet temperature probe (p/n 686216) was found split open at its end. This probe was replaced six months and 21 hours earlier to comply with AS2011-06-10.
Part Total Time: 21.0 hours

Slick 6310 Magneto
Failed Contact Points
After only 16 hours of use, the contactor pointer on the magneto separated from the contact points.
Part Total Time: 16.0 hours