NTSB Identification: WPR12LA161
14 CFR Part 91: General Aviation
Accident occurred Saturday, April 07, 2012 in Casper, WY
Probable Cause Approval Date: 11/26/2012
Aircraft: PIPER PA-28-181, registration: N30997
Injuries: 2 Minor.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

During cruise flight, the engine sustained a reduction in oil pressure followed by a total loss of power. The student pilot then performed a forced landing into a field. Subsequent examination of the engine revealed that a piston pin plug had disintegrated, the fragments of which contaminated the oil passages and caused oil starvation and the subsequent engine seizure.

The engine's manufacturer issued a service instruction warning of such piston pin wear, recommending oil filter element inspection or spectrographic oil analysis at each oil change, not to exceed 50 hours of engine operation. The engine had undergone an oil change about 8 flight hours prior to the accident and the mechanic reported that the oil filter element appeared to be normal. Based on the relatively short period between the last oil filter inspection and the engine failure, the oil filter inspection should have revealed ample evidence of piston pin wear.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

A total loss of engine power during cruise flight due to a failed piston pin plug, which resulted in engine oil contamination and subsequent oil starvation. Contributing to the loss of power was the failure of maintenance personnel to identify contaminants produced by the failing plug during the last oil filter inspection.

Full narrative available

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