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:

Multiple aircraft types reported various pushrod issues, including breakage, excessive wear, and undocumented bending.
Root causes for these failures ranged from mechanical issues like stuck valves and insufficient lubrication to manufacturing defects such as missing oil passages.
The problems primarily affected cylinder pushrods and associated components like rocker arms, often discovered during inspections or due to symptoms like metal in the oil filter.