Mooney Aircraft Corp. M20K N3567H accident near Fresno, California

Probable cause

A total loss of engine power during cruise flight due to a failure of the No. 1 piston and connecting rod assembly.

NTSB analysis

The private pilot was conducting a personal cross-country flight. During cruise, the engine experienced a catastrophic failure and a total loss of power. The pilot performed a forced landing to an airport, landed long, and collided with an airport fence. Postaccident examination of the engine revealed internal damage consistent with the initial failure of the No. 1 piston and connecting rod assembly, most likely at the piston end, which caused a cascading failure of the adjacent piston and rod assemblies. Damage to the engine components precluded an accurate assessment of the specific initiating event, and evidence suggested that the engine contained oil at the time of the failure.

The engine had been involved in a propeller strike accident about 310 flight hours prior, which required an engine teardown, examination, and replacement of two connecting rods and one piston pin. Maintenance records did not disclose which rods were replaced. Following the repair, the engine went through a 10-year period of inactivity, during which time internal corrosion occurred. No precautionary steps were taken to monitor the effects of the corrosion, such as oil filter examination or oil analysis. The extent to which the corrosion contributed to the failure of the No. 1 piston and connecting rod assembly could not be determined.

Text from the NTSB. Open the NTSB docket for WPR15LA175 for the full record.