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ASN Wikibase Occurrence # 231602
Last updated: 21 December 2019
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Type:Silhouette image of generic A333 model; specific model in this crash may look slightly different
Airbus A330-343
Owner/operator:AirAsia X
Registration: 9M-XXD
C/n / msn: 1066
Fatalities:Fatalities: 0 / Occupants: 244
Other fatalities:0
Aircraft damage: Minor
Category:Serious incident
Location:445 km SE of Alice Springs, SA -   Australia
Phase: En route
Nature:International Scheduled Passenger
Departure airport:YSSY
Destination airport:WMKK
Investigating agency: ATSB
AirAsia X flight XAX221 was en route from Sydney, Australia, to Kuala Lumpur, Malaysia when the oil pressure pump for the right engine (engine 2) of the Airbus A330 experienced a shaft failure. That shaft failure resulted in the oil pressure in engine 2 dropping rapidly to 0 psi. The aircraft’s electronic centralised aircraft monitor (ECAM) detected the drop in oil pressure and notified the flight crew through the ENG 2 OIL LO PR failure alert. In response to the alert, the flight crew commenced, but did not complete, the associated procedure. In accordance with the procedure the flight crew reduced the engine’s thrust to idle, but then elected to monitor the engine instead of shutting it down. After about 4 minutes, the flight crew returned engine 2 to normal operations. Shortly thereafter, the engine surged a number of times and eventually failed. The flight crew completed the engine failure procedure, shutting the engine down, and initiated a diversion to Melbourne. During the diversion, the flight crew attempted to relight engine 2 twice, the first shortly after the engine failure, and the second just prior to descending into Melbourne.

ATSB Findings:
The ENG 2 OIL LO PR failure, a level 3 alert, was the result of a shaft failure of the right engine oil pressure pump. A level 3 alert required immediate crew action as the failure may be altering the safety of the flight. The ECAM procedure required the flight crew reduce the engine thrust to idle and, ‘if [the] warning persists’, then shut the engine down. The flight crew probably interpreted this as a temporal requirement and not a continuation of the condition, as intended by Airbus. As a result, the flight crew continued to troubleshoot the failure. After monitoring the engine they established a belief that the warning was the result of a gauge failure. With a stated intent of further trouble shooting, the flight crew then increased the engine’s thrust. This led to the first engine stall and ultimately the engine failure.
Despite available guidance and cumulative evidence to the contrary, the flight crew determined that right engine was not damaged and could be restarted. Consequently, and contrary to the operator’s procedures, the flight crew made two attempts to restart this engine. Both restart attempts failed.
Also contrary to the operator’s procedures, the flight crew elected to divert to Melbourne following the engine failure, bypassing closer suitable aerodromes. This increased the time that the aircraft was operating in an elevated risk environment.

The operator restated the operational requirements concerning engine restarts and diversion decision making to flight crew. The operator also used the occurrence as the basis of a training package on response to engine failures, restarting failed engines and diversion decision making.



Accident investigation:
Investigating agency: ATSB
Status: Investigation completed
Duration: 3 years and 4 months
Download report: Final report


Photo of 9M-XXD courtesy

Adelaide - International (YPAD / ADL)
23 November 2013; (c) Gavin Hughes

Revision history:

21-Dec-2019 15:31 harro Added
21-Dec-2019 15:39 harro Updated [Total occupants, Narrative]

Corrections or additions? ... Edit this accident description