Accident Overview
During cruise flight, the engine suffered a partial loss of power. While descending for a precautionary landing, the engine stopped completely and the propeller ceased rotating. The pilot carried out a forced landing onto a road. During the landing roll, the right wing collided with a road sign, causing the airplane to veer to the right. It then struck a fence before coming to rest.
Engine Examination
Post-accident examination of the engine revealed that the crankshaft had failed near the rear counterweight. A metallurgical analysis determined that the failure was due to fatigue, which originated from a subsurface point.
Maintenance History
Review of the engine logbooks showed that the crankshaft was the original component installed when the engine was manufactured on April 14, 1961. The engine had accumulated a total of 4,032 hours of operation. It had been overhauled twice, with the most recent overhaul occurring in 1986. During that overhaul, the crankshaft was inspected using magnaflux methods. Since the latest overhaul, the engine had operated for 1,032 hours.