Accident Overview
During the takeoff-initial climb, the engine lost power, and the pilot performed a ditching in the ocean. The aircraft was not recovered from the water but was examined after recovery.
Engine Examination
Examination of the engine showed that the number 2 connecting rod had fractured from the crankshaft. A metallurgical examination of the connecting rod, associated bolts, nuts, and bearings revealed that the separation was not instantaneous. The first nut unthreaded from its respective bolt, after which increased loads on the opposite bolt caused the threads of the other nut to strip. This nut had partially unthreaded from its bolt. No evidence of cotter pin installation was found.
Maintenance History
The engine had undergone a field overhaul 735.31 hours prior to the accident. During an annual inspection 233.59 hours before the accident, the cylinders were removed for a blow-by condition. However, the aviation maintenance technician who performed this work stated that he did not remove the connecting rods from the crankshaft.
Occupant Protection
Review of the autopsy results and impact damage to the wreckage indicated that the occupants' use of shoulder harnesses would have significantly increased their chances of survival.