LAX93LA356

Failure of the crankshaft due to fatigue.

During a local VFR flight, the engine lost power. The pilot tried to land on an asphalt surfaced road, but was unable to reach the roadway. During the forced landing, the airplane collided with trees on uneven desert terrain and was damaged. An examination of the engine revealed that the crankshaft had failed forward of the number one journal. The fractured surfaces displayed beach marks consistent with fatigue. There was no evidence that the engine had sustained any high temperature distress or lack of lubrication. The engine had accrued about 4434 hours since new and about 1110 hours since it was overhauled on 12/10/87.

On September 17, 1993, at 1005 hours mountain standard time, a Cessna 182A, N6336B, collided with some trees during an emergency landing near Oracle Junction, Arizona. The emergency landing was precipitated by a total loss of engine power during cruise flight. The pilot was conducting a local visual flight rules personal flight. The airplane, operated by D. Genzman, dba Snoopy's Flight School, Tucson, Arizona, sustained substantial damage. The certificated private pilot and one passenger were not injured; one passenger sustained serious injuries and was subsequently hospitalized. Visual meteorological conditions prevailed. The flight originated at Ryan Field, Tucson, Arizona, at 0935. Mr. Dean Hennies, Aviation Safety Inspector [Airworthiness], Scottsdale [Arizona] Flight Standards District Office, examined the engine on October 6, 1993. The examination revealed that the crankshaft broke forward on the number one (1) connecting rod journal. The fractured surfaces displayed beach marks consistent with fatigue. There was no evidence that the engine sustained any high temperature distress. The engine displayed normal lubrication signatures. The maintenance records examination revealed that the engine had accrued about 4,434 hours since new and about 1,110 hours since major overhaul. The major overhaul was accomplished on December 10, 1987. -