What happened
Approximately one minute after takeoff, the crew observed fire warning indications for the left engine in the cockpit. In response, the pilot retarded the left engine power lever and initiated a turn back toward the airport.
The fire warning indicators continued to actuate intermittently until the crew successfully shut down the engine and deployed the engine fire extinguisher. The aircraft subsequently completed an uneventful landing. Upon arrival, ground personnel notified the captain of visible fire damage to the left engine, which prompted an emergency evacuation of the aircraft.
The investigation
An inspection of the left engine identified a leak at the no. 7 fuel nozzle, which served as the origin of the fire. The investigation found that a hole had been burned into the diffuser case. This defect allowed hot gases to escape and come into contact with oil lines, resulting in extensive fire damage to both the engine and the cowling.