Incident Summary
During cruise flight, a Cessna 182Q seaplane encountered an in-flight fire in the engine compartment, followed by a total loss of engine power. The pilot completed a successful forced landing to a lake, and local firefighters extinguished the fire. Heat damage was observed on the firewall and structural members aft of the firewall on the bottom of the fuselage.
Examination Findings
Inspection of the engine compartment identified a 10.00-inch long, fire-sleeved, steel braided, flexible fuel line that had chafed against an electrical cable approximately 5 inches from where the fuel line attached to the engine-driven fuel pump. The chafing created a hole in the fuel line and wore away the wire insulation, resulting in the in-flight fire and subsequent loss of engine power.
Modification History
Approximately 2 years, 4 months, and 11 days before the incident, the airplane was modified by a mechanic who installed a dimensionally larger engine and modified the firewall per a Supplemental Type Certificate (STC). The engine provided to the mechanic came from the STC holder with the 10.00-inch fuel line already installed, though the original STC-approved length was 8.25 inches. Prior to STC approval, the FAA Aircraft Certification Office inspected a modified airplane and the submitted drawings, but the drawings depicted only modifications and not previously installed lines or hoses.
Post-Accident Observations
The mechanic who performed the modification inspected five similar airplanes after the accident and found that two had chafing of the same electrical cable against different fuel lines. He noted that the area where the fractured fuel line was located was "tight."