Accident Sequence
The pilot, the sole occupant and holder of a private pilot certificate, was conducting a cross-country business flight when the engine ceased operating. The pilot executed a forced landing approximately 250 feet short of a dirt airstrip. The airplane was destroyed by the impact and subsequent post-impact fire, and the pilot sustained fatal injuries.
Engine Examination
A post-accident examination of the engine identified a broken crankshaft on the crankcheek adjacent to the number 1 cylinder. The crankshaft had been replaced 42 hours before the accident. This replacement crankshaft was sourced from an engine that had accumulated about 1,000 hours of total operation and had previously experienced a separation of the number 1 cylinder from the engine case. After inspection, the crankshaft was deemed serviceable and installed in the accident airplane's engine.
Metallurgical Findings
Metallurgical examination of the fractured crankshaft revealed a high cycle fatigue failure consistent with surface-initiated cracking. A metallurgical report indicated that surface cracking would not be expected in the area of failure unless prior damage to the surface had occurred.