Aerostar Acft Corp Of Texas M20E N6807V accident near Clever, Missouri

Probable cause

The failure of the engine No. 2 connecting rod bearing for reasons that could not be determined due to the extensive secondary engine damage.

NTSB analysis

The flight instructor reported that, after takeoff on the instructional flight, the engine was running smoothly before it "missed" or "hesitated." The flight instructor initiated a return to the airport; shortly thereafter, the engine began to make loud noises and vibrate, ultimately experiencing a total loss of power. The flight instructor performed a forced landing to a field, resulting in substantial damage.

Examination of the engine revealed that the No. 2 connecting rod had failed. Remnants of the connecting rod bearing found within the oil pan exhibited evidence of bearing failure and extrusion. Due to the extensive secondary engine damage, the reason for the failure of the No. 2 bearing could not be determined. The engine was overhauled 11 years 6 months before the accident, and had accumulated about 16 hours of flight time in the preceding 3 years. Guidance published by the engine manufacturer stated that abnormal wear could occur during engine start due to a loss of protective oil film after an extended period of inactivity and recommended that all engines not in continuous service be overhauled every 12 years.

Text from the NTSB. Open the NTSB docket for CEN17LA110 for the full record.