What happened
During a flight, the aircraft experienced a loss of engine power. This loss of power was caused by the engine being starved of fuel. The failure originated when the fuel transfer tube moved significantly out of its position within the nozzle adaptor, allowing pressurized fuel to escape the system.
The investigation
The investigation focused on the assembly of the fuel transfer tubes and nozzles following a recent replacement. Investigators examined the hardware at the site of the leak and noted that the locking plate was entirely missing from the assembly. While the fasteners were found to be installed and the locking plate mounts showed no signs of damage, the absence of the plate was critical. The investigation determined that the locking plate was likely not reinstalled during the maintenance process when the tubes and nozzles were being fitted.
Findings
- The missing locking plate allowed the fuel transfer tube to gradually migrate out of the nozzle adaptor.
- This migration occurred over a period of 86 flight hours following the maintenance event.
- The movement of the tube eventually allowed fuel under pressure to escape from the nozzle adaptor, resulting in the engine power loss.