Incident Overview
While cruising at 9500 feet, the pilot observed smoke emanating from the left engine cowling. Attempting to reduce power, the pilot found the left throttle lever immovable. After turning the left fuel selector off, the fire initially extinguished but reignited approximately three minutes later.
Emergency Descent and Landing
During the subsequent emergency descent, all electrical power was lost. The copilot manually cranked down the landing gear. Upon touchdown, the left main landing gear collapsed as the wing continued to burn.
Examination Findings
Post-incident examination of the engine revealed that the fuel pressure return line fitting on the firewall was only finger-tight. The opposite fitting remained secure. The maintenance manual specifies a torque of 30–40 inch-pounds for that fitting.
Pilot Actions
The pilot did not follow the approved emergency procedures for an in-flight wing or engine fire.