Primary finding
Probable cause
The corroded, and separated, magnetic chip detector plug which allowed the loss of all engine oil and the engine's subsequent seizure. Factors were the inadequate 100 hour inspection, and the high vegetation in the forced landing field.
Investigator assessment
Analysis narrative
While conducting an aerial application flight, the engine seized & a forced landing was made into a corn field. The airplane nosed over during the landing roll. Examination of the airplane revealed that engine oil covered its belly. The chip detector in the oil sump of the engine was found broken, with the detector electrode held on by its transmission wire. The open detector port had allowed all of the engine oil to escape. Metallurgical examination of the detector electrode revealed that it had separated because of corrosion. The operator's mechanic stated that he usually found about one tablespoon of water in the engine sump during 100 hour oil changes.
Source record
Factual narrative
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