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:

Numerous aircraft types (Cessna, Diamond, Maule, Piper) reported a variety of pushrod issues, including breakage, excessive wear, scoring, bending, and manufacturing defects.
Observed causes for these failures included mechanical stress from related components (e.g., stuck valves), insufficient lubrication, or intrinsic manufacturing flaws like undrilled pushrods.
Pushrod problems frequently resulted in, or were accompanied by, damage to other engine components such as rocker arms and lifters.