What happened
The aircraft was operating following a landing phase when the pilot noticed the left engine catch fire while taxiing on the ground. The incident occurred during normal ground operations after the completion of the flight segment.
The investigation
A detailed examination of the affected engine and fuel system components was conducted to determine the root cause of the fire. Inspectors focused on the integrity of the fuel delivery system, specifically looking for signs of leakage or mechanical failure that could have led to ignition sources near hot engine parts.
Findings
The investigation identified a critical maintenance error in the fuel system assembly. The fuel line connecting the fuel pump to the fuel controller was found to be cross-threaded at the fitting located on the fuel controller. This improper installation prevented the total mating of the fitting surfaces, which is essential for creating a sealed connection.
Because the threads were not aligned correctly during installation, the fitting could not achieve the necessary seal. This likely allowed fuel to leak from the high-pressure line onto hot engine components, resulting in the fire observed during taxi. The maintenance records did not provide sufficient information to determine when the most recent work on this specific fuel line was performed, leaving a gap in the service history.
fuel line cross-threading was the primary mechanical failure identified. fuel leakage from the unsealed fitting caused the engine fire. improper installation of the fitting prevented proper sealing.