Accident Overview
The aircraft experienced a total loss of power during flight due to a complete loss of engine oil. The pilot performed a forced landing on a grass field. Because the available landing areas were unsuitable, the aircraft nosed over during the landing.
Maintenance History
On December 11, 1985, the oil filter adapter and its O-ring were replaced. The mechanic informed the aircraft owner via a written work order that the threads on the adapter were worn and broken.
Investigation Findings
During the engine teardown, it was found that the oil filter adapter had slipped past the threads in the oil pump housing. This condition led to the loss of oil, which caused the total loss of power.
Landing and Outcome
The forced landing was made on a grass field. Due to the unsuitable landing area, the aircraft nosed over upon touchdown.