Incident
Shortly after departure, the aircraft experienced a total loss of engine power. The pilot was forced to ditch in open water. The occupants successfully egressed the aircraft and were subsequently rescued by a recreational vessel.
Examination
Examination of the engine revealed a fracture hole near the number 2 cylinder. This hole was the result of the number 2 cylinder connecting rod fracturing due to fatigue. The fatigue fracture displayed multiple origins, consistent with relatively high cyclic stress. This stress likely occurred as excessive clearances developed between the bearing and the crankshaft journal.
The failure of the number 2 connecting rod bearing was attributed to high heat and high stress. The bearing failure may have been caused either by a material defect in the bearing itself or by a disruption in the oil lubrication supply to the bearing/journal interface. Either situation can cause similar damage patterns, including excessive heating and subsequent bearing failure.
Probable Cause
The official probable cause was determined to be a total loss of engine power due to the failure of the No. 2 bearing, which resulted in the number 2 connecting rod failing due to fatigue, high heat, and stress.