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:

Several aircraft models (Cessna, Piper, Maule) reported various issues with engine cylinder pushrods, including abnormal wear, breakage, and manufacturing defects such as improper drilling for lubrication.
Common contributing factors to these engine pushrod failures included insufficient lubrication reaching the top of cylinders or specific defects preventing oil flow, and in one case, a valve stuck in the closed position.
An isolated incident on a Diamond DA42 involved bent aileron control rod ends, with no corresponding documentation found in the maintenance manual.