What Happened
Witnesses observed the aircraft perform a rolling takeoff and become airborne by the crossing runway, approximately 1,300 feet down the 6,600-foot runway. The aircraft then climbed at an approximate 40-degree nose-high attitude to about 1,000 feet. Subsequently, it entered a steep left-hand banking turn, the nose dropped, and the aircraft rotated up to about four times before colliding with flat terrain adjacent to the departure end of the runway threshold.
Aircraft and Pilot
On-site documentation found no evidence of a flight control malfunction. The left engine's gearbox section experienced a high-cycle fatigue failure of the high-speed pinion journal bearing oil supply tube, with subsequent degradation of the bearings, resulting in a partial power loss to the left engine. The pilot had recently purchased the aircraft and accumulated approximately 11 hours since the purchase. He stated to personnel at the purchase location that he had not received nor did he need recurrent training in this aircraft, as he had several thousand hours in the aircraft. Flight logs indicated the pilot had accumulated about 551 hours in a Mitsubishi, but the last time he had flown this make and model was 14 years prior to the accident. Logbook entries showed only a few hours of flight time in all aircraft during the approximately two years prior to the accident. Personnel who flew with the pilot in the make and model involved described the pilot as "proficiency lacking."
Performance Calculations
Normal takeoff calculations for the aircraft with flaps configured to 5 degrees indicated a ground run of 2,900 feet, a rotation speed of 106 KCAS, and 125 KCAS for climb out, with a maximum pitch attitude of 13 degrees. Performance calculations indicated the aircraft was capable of lifting off where witnesses observed and climbing to 1,000 feet agl by the end of the runway. To achieve this, the aircraft would have rotated at approximately 84 KCAS and climbed at an airspeed below Vmc (100 KCAS) and close to power-off stall speed (86 KCAS) with 5 degrees of flaps.
Emergency Procedures
The airplane's flight manual specified that if an engine failure occurs during takeoff climb with the landing gear fully retracted, the emergency procedures are to maintain 140 KCAS, flaps at 5 degrees, the failed engine condition lever to EMERGENCY STOP, and the failed engine power lever to TAKEOFF. On-site documentation found the left side condition lever in the takeoff/land position and the power lever halfway between takeoff and flight idle.