Accident Sequence
Approximately 20 minutes after takeoff, the pilot reported that the right engine had lost power and the aircraft could not maintain altitude. Air traffic control provided vectors for an emergency landing, but the aircraft crashed in a wooded area about 3 miles from the airport. Evidence indicated that the landing gear and flaps had been extended and the aircraft had entered a turn before impacting the trees.
Aircraft and Weight
The aircraft was estimated to be 844 lbs over its maximum weight limit, and its center of gravity (CG) limit was exceeded by about 4.8 inches. Six of the passengers were not restrained by seat belts. The aircraft's weight and balance exceeded limits, a condition attributed to the pilot in command's improper preflight planning.
Engine Examination
Post-crash examination revealed unsymmetrical wear on the blades of the right turbocharger. Its thrust spacer, part number 406990-9004, was worn, and there was evidence of oil leakage. The right engine's 13-quart oil system contained only 6.85 quarts of oil remaining. Both propellers had evidence of low to moderate power and neither was feathered. The right turbocharger failure was linked to wear and improper maintenance. The left turbocharger was not specifically mentioned in the failure.
Pilot and Passengers
An associate estimated that the pilot had only 4 to 6 hours of rest in the previous 3 to 4 days, indicating fatigue. The pilot was also noted as lacking familiarity with the aircraft. The official findings cited improper in-flight planning/decision, improper emergency procedure, premature gear and flap extension, and failure to maintain airspeed (Vmc). The passenger briefing was inadequate, and seat belts were not used by six passengers.
Probable Cause
The official probable cause findings include: loss of engine power (partial) due to mechanical failure/malfunction, with the turbocharger worn and failed, maintenance improper, oil leakage, and the pilot not feathering the propeller. During the forced landing, the pilot's improper preflight planning led to overweight and CG exceedance, inadequate passenger briefing, and passengers not using seat belts. During the loss of control in flight, contributing factors included dark night conditions, improper in-flight planning/decision, pilot fatigue, improper emergency procedure, lack of familiarity with aircraft, premature gear and flap extension, and failure to maintain airspeed (Vmc). The collision with trees was the final occurrence.