Incident Summary
During cruise flight, the pilot reported that the right engine cowling partially separated and the left forward cylinder of that engine separated, followed by an engine compartment fire. He attempted to feather the propeller but was unable to do so. He initiated a descent to extinguish the fire and was successful, but after leveling off, he was unable to maintain directional control. He ditched the airplane and both he and the passenger exited the aircraft. The pilot dragged the seriously injured passenger with him to a nearby island where they were rescued the following day.
Investigation
The aircraft was not recovered; therefore, no determination could be made as to the reason for the separation of the cylinder. Review of the aircraft logbook indicates that on 8/27/91, the No. 5 cylinder of the right engine was removed and replaced. Also, the No. 1 cylinder was removed and reinstalled following repair. There were no further entries in the aircraft logbook regarding cylinder removal or replacement to the right engine.
Probable Cause
For undetermined reason(s), the right engine failed and the right propeller would not feather.