Accident Overview
During the flight, an inflight fire developed at the rear of the left engine. Investigation determined that the fire originated from the fitting of the inlet fuel line to the engine-driven fuel pump. The fitting had been tightened to more than one and a half turns beyond the finger-tight position. This improper installation led to the fire.
Wing Separation
As the fire progressed, the left wing separated from the fuselage. The separation occurred when the lower spar cap of the wing reached a temperature near its melting point, resulting in the wing separation.
Maintenance and Pilot Information
The pilot was also a certified Airframe and Powerplant (A&P) mechanic. He had performed maintenance on the aircraft and had personally assisted in the installation of the left engine. This maintenance event took place 19.8 flight hours prior to the accident.
Toxicology Findings
Post-accident toxicological analysis revealed the presence of a metabolite of phendimetrazine. This substance is a drug that can only be legally obtained via prescription. The presence of this metabolite is considered disqualifying for flying.