Pushrods

The number 3 cylinder exhaust pushrod broke, due to a valve stuck in the closed position. The valve was not stuck at the time of the investigation. No marks were seen on the top of the piston as viewed through a borescope. The lifter came apart as a result of the broken push rod but appears to have been operating properly prior to the event.

Editorial Staff

Wednesday, May 17, 2017 at 12:00 AM ET

Verified

Key Takeaways:

Various aircraft models (Cessna, Diamond, Maule, Piper) experienced diverse pushrod issues, including breakage, abnormal wear, scoring, and bending.
Reported problems affected both engine cylinder pushrods and aileron control rods, with some occurring at relatively low component total times.
Root causes and contributing factors identified include stuck valves, insufficient lubrication, and manufacturing defects like undrilled oil passages.