Accident Overview
An airplane was substantially damaged during a forced landing following a loss of engine power. According to the pilot, shortly after takeoff, the engine "abruptly and smoothly rolled back." Movement of the power control lever had no effect, and use of the manual override (MOR) system did not restore engine power. The pilot secured the engine and executed a forced landing on a roadway. During the landing rollout, the airplane's wing struck two utility poles.
Engine Data and Inspection
Data downloaded from the accident aircraft indicated that the recorded engine interstage turbine temperature (ITT) exceeded published limits during the event. A post-accident engine inspection revealed turbine damage consistent with an over-temperature event. Additionally, the inspection revealed a leak in the compressor discharge pressure (CDP) sensor bellows within the fuel control unit (FCU).
Fuel Control Unit Findings
The leak prevented the bellows assembly from responding to throttle inputs and resulted in the FCU providing minimum fuel flow to the engine regardless of the throttle setting. Following this accident, an improved FCU design incorporating a more robust bellows design was released and retrofitted into the entire in-service and production fleet. The airframe manufacturer also issued a revision to the pilot's operating handbook to provide an improved procedure for use in the event of an in-flight engine power loss and updated information regarding the Manual Override (MOR) system.