Aviation safety investigations & reports

Engine failure involving Airbus A330, 9M-XXD, 445 km SE of Alice Springs, South Australia, on 16 August 2016

Investigation number:
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final Report

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What happened

While en route from Sydney, New South Wales, to Kuala Lumpur, Malaysia, the oil pressure pump for the right engine (engine 2) of an AirAsia X 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.

What the ATSB found

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.

What's been done as a result

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.

Safety message

This occurrence demonstrates the importance of crews adhering to standard operating procedures. It also identifies the need for clarity in the construction of procedures, and that where there is not a need for immediate response, to look at the full contextual and available information before deciding on a plan of action.

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[Download  PDF: 1.07MB]

The occurrence


Safety analysis


Safety actions

General details

Sources and submissions


General details
Date: 16 August 2016   Investigation status: Completed  
Time: 2310 CST   Investigation level: Systemic - click for an explanation of investigation levels  
Location   (show map): Alice Springs 445 km SE   Investigation phase: Final report: Dissemination  
State: South Australia   Occurrence type: Engine failure or malfunction  
Release date: 19 December 2019   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Airbus  
Aircraft model A330-343X  
Aircraft registration 9M-XXD  
Serial number 1066  
Operator AirAsia X  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Sydney, NSW  
Destination Kuala Lumpur, Malaysia  
Last update 03 April 2020