Accident Summary
A pilot who had recently purchased an aircraft experienced a total loss of engine power while cruising. The pilot ditched the aircraft in a harbor, where it subsequently sank. The aircraft was later recovered for examination.
Examination Findings
Following recovery, the engine was examined and its crankshaft was found to be fractured. A metallurgical examination revealed a surface origin fatigue crack in the area of the No. 4 crankshaft cheek, between the No. 2 main journal and the No. 3 crankpin journal. The fracture had initiated in the forward fillet radius of the No. 2 main journal. No evidence of any preexisting material defects was found in the crankshaft metal.
Maintenance Background
Approximately 10 years and 1166 operating hours before the accident, the engine had reportedly undergone a major overhaul. The aircraft's maintenance records were incomplete, and the adequacy of the previous maintenance could not be adequately documented.