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Summary

Summary

Updated: 5 May 2017

Completion of the draft investigation report has been delayed by competing priorities and workload of the investigator in charge. It is now anticipated for release to directly involved parties (DIP) for comment in July 2017. Feedback from those parties over the 28-day DIP period on the factual accuracy of the draft report will be considered for inclusion in the final report, which is anticipated to be released to the public no later than September 2017.

 

 

Updated: 12 January 2017

On the evening of 16 August 2016, at 2137 Eastern Standard Time,[1] an AirAsia X Airbus A330‑343X, registered 9M-XXD, departed Sydney, New South Wales on flight XAX221 to Kuala Lumpur, Malaysia. At about 2343, as the aircraft was in cruise at flight level[2] (FL) 380 and 445 km south-east of and tracking towards Alice Springs, the aircraft’s engine fault monitoring systems detected low oil pressure in the right engine (ENG 2).[3] This fault was transmitted to the Flight Warning Computer (FWC), which in turn:

  • illuminated the MASTER WARN light and the aural warning signal on the Glareshield Panel (Figure 1)
  • through the Electronic Centralized Aircraft Monitor:

-    displayed the relevant warning message on the Engine/Warning Display (E/WD) and its associated procedure for the flight crew to follow

-    on the System Display, displayed the relevant system synoptics corresponding to the warning on the Electronic Centralized Aircraft Monitor.

Figure 1: Front panels, showing the E/WD and System Display on the Main Centre Panel, and master warning/caution lights on the Glareshield Panel

Figure 1: Front panels, showing the E/WD and System Display on the Main Centre Panel, and master warning/caution lights on the Glareshield Panel

Source: Airbus

The following sequence of events was recorded by the aircraft’s Flight Data Recorder:

2343:20

ENG 2 oil pressure dropped from 90 to 1 psi over a period of 7 seconds.

2343:33

The FWC illuminated the master warning light and the E/WD displayed the red warning message[4] ENG 2 OIL LO PR.

2343:47

The ENG 2 thrust lever was retarded to the idle detent.

2344:04

The left engine (ENG 1) thrust lever was advanced to the maximum continuous thrust detent.

2347:14

The ENG 2 thrust lever was advanced from the idle detent to the climb detent. ENG 2 accelerated accordingly.

2347:55

ENG 2 surged[5] and the engine’s automated surge recovery processes operated correctly.

2347:57

The FWC illuminated the master caution and the E/WD displayed the amber caution message ENG 2 STALL.[6]

2347:59

The ENG 2 thrust lever was retarded to the idle detent.

2348:02

ENG 2 surged and recovered again and separately the flight crew declared an emergency, requested descent and identified their
probable intention of diverting to Melbourne Airport.

2348:37

ENG 2 surged for a third time.

2348:43

The FWC illuminated the master caution light and the E/WD displayed the amber caution message ENG 2 FAIL.

2348:50

Flight crew shut down ENG 2.

Following the engine failure, the aircraft was descended to FL 230. Just prior to reaching that altitude, at 0002:14 on 17 August, the flight crew attempted to restart ENG 2. The restart was unsuccessful, due to the HP assembly not reaching the required rotational speed for fuel to be fed to the engine. The attempted restart was discontinued at 0003:37.

At 0132:00 a second restart was attempted by the flight crew. The flight data indicated a starter‑assisted relight. In this instance, the HP assembly rotational speed was sufficient to feed fuel to the engine, and at 0132:36 a successful relight occurred. During the restart, the flight crew felt vibrations from the engine, and at 0132:46 shut down ENG2.

The aircraft landed at Melbourne Airport at 0159 on 17 August 2016.

Initial examination of ENG 2 found the following:

  • there were no obvious engine leaks
  • oil tank contents were reported as full
  • the engine magnetic chip detectors and oil filters were described as clean
  • the oil pump drive shaft neck was fractured (Figure 2)
  • the HP assembly was seized due to bearing stress
  • damage to the HP assembly ball and roller bearings was consistent with engine operation without oil pressure.

Figure 2: Fractured oil pump drive shaftFigure 2: Fractured oil pump drive shaft
Source: Rolls-Royce

The investigation is continuing and will review the:

  • company and flight crew procedures
  • flight crew actions, including their attempts to restart ENG 2
  • air traffic control data
  • findings of the engineering examination
  • human factors aspects of the occurrence.

The scope of this investigation has been expanded consistent with the ATSB’s increased understanding of the nature of the occurrence. This has impacted on the time taken to complete the investigation. It is now anticipated that the draft investigation report will be released to directly involved parties (DIP) in March 2017 for comment on the factual accuracy of the draft. Any DIP comments over the DIP period will be considered for inclusion in the final report, which is expected to be issued to the public no later than May 2017.

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The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

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[1]     Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.

[2]     Flight level: at altitudes above 10,000 ft in Australia, an aircraft’s height above mean sea level is referred to as a flight level (FL). FL 380 equates to 38,000 ft.

[3]     The aircraft was fitted with Rolls Royce Trent 700 series engines. These engines have three compressor turbine assemblies, the Low Pressure (LP) assembly, the Intermediate Pressure (IP) assembly and the High Pressure (HP) assembly.

[4]     Red warning messages are for configuration or failure requiring immediate action.

[5]     The gross breakdown of airflow through the compressor, resulting from a local stall. Often used synonymously with the term ‘stall’. Often accompanied by a loud bang, the engine may self-recover normal airflow. Large, more complex turbine engines also have automated surge recovery processes that are designed to assist in recovering the engine’s airflow to normal. 

[6]     Amber caution messages are for configuration or failure requiring awareness but not immediate action.

 

 

____________________________

Published: 11 November 2016

The ATSB is investigating an engine shut down involving an AirAsia X Airbus A330, registered 9M-XXD, 445 km SE of Alice Springs Airport, South Australia, on 16 August 2016.

During cruise, the flight crew received a low oil pressure warning from the right engine. The engine was shut down and the flight crew diverted the aircraft to Melbourne. There were no injuries and the aircraft was not damaged.

As part of the investigation, the ATSB will interview the captain and gather additional information.

 

 
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