What happened
During a descent into Perth, the right engine of a Boeing 787, registration 9V-OJE, ceased operation. Following the engine failure, the flight crew executed the required emergency checklists and successfully performed a single-engine landing. There were no injuries reported following the incident.
The investigation
An investigation by the engine manufacturer, Rolls-Royce, determined that the shutdown was caused by a blocked inlet filter located on the fuel metering valve (FMV) servo assembly. This blockage prevented the electronic engine controller (EEC) from effectively regulating fuel pressures within the servo. Specifically, when the EEC attempted to increase fuel flow from sub-idle to idle levels, the system failed to respond with sufficient speed, leading to the engine shutdown.
The source of the blockage was identified as debris originating from worn journal bearings within the secondary high-pressure (HP) fuel pump driven gear. Rolls-Royce noted that during a period between late 2018 and early 2019, the operator's fleet of 787 aircraft showed a particular vulnerability to premature wear in these specific secondary HP pump journal bearings.
Findings
- The primary cause of the engine shutdown was insufficient fuel delivery resulting from low pressure in the fuel metering valve servo assembly.
- Debris from worn secondary high-pressure fuel pump bearings obstructed the inlet filter.
- While various elements such as maintenance, fuel quality, and pump design were considered, investigators could not isolate a single definitive cause for the increased wear rate beyond the identified susceptibility within the fleet during the specified timeframe.