Incident Summary
The pilot of a twin-engine airplane performed a ditching in the Pacific Ocean after experiencing a loss of engine power and an in-flight engine fire while at cruise altitude. The flight was operating at 1,000 feet mean sea level when the pilot noted a loss of power in the right engine. Simultaneously, passengers observed a fire emanating from the right engine cowling. The pilot secured the right engine and feathered the propeller. Attempting to reach a nearby airport, the pilot determined that the airplane could not maintain altitude and decided to ditch in the ocean.
Passenger Evacuation
Prior to the forced landing, the pilot instructed passengers to don life jackets and assume the crash position. After the aircraft touched down on the water, all but one passenger exited through the main cabin and pilot doors. The remaining passenger was reportedly frightened and could not swim. One survivor saw this passenger still seated with the seat belt fastened and the life vest inflated. The pilot and passengers were subsequently rescued from the ocean by a helicopter and a boat.
Postaccident Examination
Examination of the aircraft revealed that the right engine's oil converter plate gasket had deteriorated and extruded from behind the converter plate. This allowed oil to spray into the accessory section, resulting in the engine fire. The engine manufacturer had previously issued a mandatory service bulletin (MSB) requiring inspection of the gasket every 50 hours for evidence of extrusion or oil leakage. Maintenance records indicated that the inspection was performed 18.3 hours before the accident. At the time of the incident, the right engine had accumulated 386.8 hours since its last overhaul and gasket replacement.
The MSB was issued one month before the accident after the manufacturer received reports of certain oil filter converter plate gaskets extruding around the plate. Subsequent tests submerged exemplar gaskets in engine oil heated to 245 degrees Fahrenheit; after about 290 hours, the gasket material showed deterioration similar to that of the accident gasket. Investigation revealed that the manufacturer had recently changed gasket suppliers, leading to a shipment of gaskets that did not meet specifications.
Safety Actions
As a result of the accident, the engine manufacturer revised the MSB to require gasket replacement every 50 hours. The Federal Aviation Administration followed by issuing an airworthiness directive mandating the replacement of the gasket every 50 hours.