Accident Description
Shortly after takeoff, the pilot observed that the oil pressure began decreasing. He turned to return to the departure airport, but the engine failed, and the airplane crashed into a lake near the airport.
Investigation Findings
The airplane was recovered, and examination of the engine revealed that an oil hose from the oil pump to the oil cooler inlet had failed in two places inside the protective fire sleeve. The fire sleeve was oil-soaked and internally contained metal particles. The failed oil hose was manufactured in the third quarter of 1987 and had been installed following an engine overhaul on July 22, 1987.
Further examination of the engine revealed that three of the six cylinder connecting rods failed due to lack of lubrication. The remaining three connecting rods were found to be heat distressed, and their associated rod bearings extruded.
Engine Service History
Review of the engine logbook revealed that the engine had been operated for about 53 hours since the last inspection in November 1994.