Incident Overview
During flight, the pilot heard a loud pop and experienced engine vibrations. Shortly thereafter, the engine suffered a partial loss of power. The pilot declared an emergency and was provided vectors toward a grass airstrip.
Emergency Descent and Landing
The pilot was unable to locate the grass airstrip while en route. Before reaching the intended landing area, the engine experienced a total loss of power. The airplane was subsequently landed in a plowed corn field.
Post-Accident Inspection
A post-accident examination revealed that the crankshaft had separated between the No. 3 main bearing journal and the No. 5 cylinder crankpin. The separation was attributed to fatigue cracking. Additionally, TCM Service Bulletin 92-16, which addresses crankshafts manufactured from non-vacuum arc remelted steel, had not been complied with.