What happened
The flight was operating as a scheduled international commuter service when the crew observed flames originating from the number one engine while the aircraft was in the climb phase. In response to the emergency, the crew immediately initiated the applicable emergency checklist procedures and discharged two fire extinguisher bottles into the affected engine compartment.
Despite the discharge of the extinguishing agents, flames continued to exit the engine tailpipe. Recognizing that the situation could not be resolved in flight, the crew executed a forced landing at an intermediate airport. Upon touchdown and shutdown of the aircraft systems, the fire ceased completely.
The investigation
Post-accident examination of the number one engine revealed significant mechanical failures. The aft turbine bearing had failed and showed clear evidence of being mis-aligned during its original installation. Additionally, investigators noted that the bearing retainer exhibited no evidence of being nitrided as required by specifications, a deficiency that accelerated the failure process.