Accident Details
A commercial pilot was conducting an air taxi cargo flight to a remote destination. Approximately 20 minutes after departure, the engine suddenly ceased operation. The pilot executed an emergency landing on rough terrain within a stream bed.
Post-Accident Examination
The aircraft was recovered five months later. An examination of the engine disclosed that the #2 main bearing had failed and the crankshaft fractured through the crank cheek between the #2 rod and #2 main bearing journals. The #2 main bearing was severely fragmented and deformed, and the number 2 main bearing saddle was severely deformed.
A metallurgical examination of the crankshaft indicated failure due to fatigue. The crankshaft conformed to the manufacturer's material specifications for hardness and nitriding.
Engine History
Records showed that the engine had been rebuilt by the manufacturer on July 23, 1992, and installed in the airplane on September 3, 1992. After rebuilding, it had accumulated 1,154 hours of flight time. At 1,004 hours, the oil pump had been serviced due to low oil pressure. During a 100-hour inspection at 1,140 hours, metal was found in the oil filter and the #4 cylinder was changed.