Incident Overview
While en route from Sydney, New South Wales, to Kuala Lumpur, Malaysia, the oil pressure pump drive shaft for the right engine (engine 2) of an AirAsia X Airbus A330 failed. This failure caused the oil pressure in engine 2 to drop rapidly to 0 psi. The aircraft's electronic centralized aircraft monitor (ECAM) detected the pressure loss and alerted the flight crew with an ENG 2 OIL LO PR alert and associated warning signals.
Crew Actions
In response to the ECAM alert, the flight crew reduced the engine's thrust to idle in accordance with the displayed procedure. However, instead of shutting down the engine as intended by the procedure, they chose to monitor it. After nearly four minutes, the crew returned the engine 2 thrust lever to the normal inflight position, increasing engine thrust. Shortly thereafter, the engine surged multiple times and eventually failed.
Engine Failure and Diversion
Following the engine failure, the flight crew completed the engine failure procedure, shutting down the engine, and initiated a diversion to Melbourne, Australia. During the diversion, the crew attempted to relight engine 2 on two occasions: once shortly after the engine failure, and again just prior to descending into Melbourne.
Investigation Findings
Rolls Royce determined that the drive shaft failed due to fatigue cracking, a failure mode that had not been observed previously for this component. The investigation also examined the flight crew's response to the oil pressure alert, the attempted relights, and the diversion decision, as well as the operator's internal investigation.