Event Summary
After takeoff from runway 09, the aircraft initiated a climbing left turn. At approximately 1,000 feet, the #2 (right) engine backfired, emitted flames, and lost power. The captain instructed the copilot to feather the #2 propeller, which the copilot initiated using the feathering button. When the captain requested extension of the landing gear and flaps, the copilot released the feathering button. The button did not remain engaged, contrary to the system design.
The aircraft arrived on a left downwind abeam the landing area at 500 feet and 95 to 100 knots. The captain turned toward the runway, then ordered the gear and flaps retracted and initiated a go-around by increasing the left throttle without increasing propeller speed. A right turn was made, and the aircraft eventually crashed about 3 miles from the runway.
Emergency Procedures and Flight Crew Actions
The emergency procedure for engine fire or failure specified feathering the propeller and moving the respective fuel selector to the 'OFF' position. The best single-engine speed was listed as 85 knots. During the event, the crew did not increase the left engine rpm in accordance with emergency procedures.
Postaccident Examination
Examination revealed the propellers were found unfeathered. The right engine fuel selector was in the main tank position. The number 11 cylinder on the right engine was cracked. Evidence of fire was present adjacent to that cylinder on the cowling, including scorching, sooting, and a burned-through area on the underside of the right engine cowling. The copilot indicated a previous problem with the feathering system, but maintenance records contained no previous discrepancies regarding this anomaly.
Probable Cause
Failure of the #11 cylinder on the right (#2) engine, which resulted in an in-flight fire and loss of power in that engine; and a malfunction/failure of the #2 feathering system, which led to a subsequent forced landing before the flight crew could return to the airport. A factor related to the accident was failure of the flight crew to increase the left (#1) engine rpm (in accordance with emergency procedures) after loss of power in the #2 engine.