Incident Overview
A pilot reported that during cruise flight, the engine began to run rough and subsequently experienced a total loss of power. The pilot executed a forced landing, during which the airplane collided with a utility pole.
Engine Examination
Post-accident examination of the engine revealed that the crankshaft had separated into two pieces, with an additional crack present. Review of maintenance records showed that the crankshaft had been overhauled by Engine Components, Inc., in San Antonio, Texas. During the first magnetic particle inspection, the crankshaft was considered for rejection due to heat cracks in the area of the number 3 main journal. The main and rod journals were then ground and renitrided. Subsequently, the crankshaft underwent two additional magnetic particle inspections and was returned to service.
Crankshaft Findings
Further examination of the crankshaft revealed that preexisting fatigue cracks had propagated at least 75 percent of the crank cheek wall. The accident occurred approximately 9 flight hours after the crankshaft inspections, which were conducted in December 1996.