Aviation safety investigations & reports

Ground handling occurrence involving Airbus A330, 9M-MTB, Melbourne Airport, Vic, on 31 March 2016

Investigation number:
Status: Completed
Investigation completed

Final Report

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What happened

On 31 March 2016, an Airbus A330-323, registered 9M-MTB and operated by Malaysia Airlines Berhad (Malaysia Airlines), was being prepared and boarded for a flight from Melbourne Airport, Victoria, to Kuala Lumpur, Malaysia. The captain engaged the aircraft’s park brake before carrying out an external inspection of the aircraft. The resulting lit park brake indicator light on the nose landing gear led the aircraft maintenance engineer to assume that the park brake would remain on. Thinking that the aircraft would remain secure, the maintenance engineer removed the main landing gear chocks out of sequence with the relevant procedure and without informing the others in the ground crew. The ground crews did not check the main gear chocks before removing the nose gear chocks to attach the tow tractor to the nose gear. Unaware that no chocks were in place, and out of sequence with the relevant procedure, the captain released the park brake on return to the flight deck. The aircraft rolled back about 3 m and struck the aerobridge. The aircraft’s forward-left door and hinges, and the aerobridge were damaged. There were no injuries.

What the ATSB found

The ATSB found that the ground and flight crew procedures were not well harmonised, leading to reduced cohesion between the crews, and that the tractor operator’s procedures did not match the way tasks were carried out locally. These problems reduced the likelihood that the respective procedures would be followed correctly. In addition, the flight crew and engineers did not explicitly convey their actions and intentions to the others, resulting in a number of missed opportunities to discover the resulting procedural errors.

What's been done as a result

The engineering company, tractor operator and Malaysia Airlines each planned or initiated safety action in response to this occurrence. The engineering company introduced standard procedures and initiated periodic operational safety inspections at all ports. The tractor operator developed a written procedure to incorporate local differences in work practices and improve coordination. Malaysia Airlines reported that it was planning to amend its procedures so that flight crews advise ground crews whenever the park brake is about to be released. As an interim measure, Malaysia Airlines sent A330 flight crews a reminder to communicate with ground crews before releasing the park brake to verify that chocks are in place.

Safety message

The ATSB stresses the importance of organisations ensuring that ground and flight crew procedures are harmonised to increase the likelihood that potential problems or mistakes are detected before causing harm. It is also important that local variations to procedures are formalised to reduce the risk of the inconsistent completion of tasks, and to improve the organisation’s ability to identify and address potential safety concerns. In addition, the ATSB encourages crews to highlight any procedural problems to their operator in order for them to be reviewed and enhanced as appropriate.

Importantly, when about to perform a key action like removing chocks or releasing the park brake, crews should consider checking with others to identify potential conflicts between tasks. This can reduce the risk of unintentional aircraft movement.

Download Final Report
[Download  PDF: 637KB]
Alternate: [Download  DOCX: 346KB]

The occurrence

Safety analysis


Safety issues and actions

Safety Issue

Go to AO-2016-028-SI-01 -

Coordination of activities related to pushback

The procedures provided to ground and flight crews by Malaysia Airlines Berhad and the towbarless tractor operator did not provide clear guidance or instruction on coordinating activities related to pushback and, in the case of the tractor operator, were informally replaced by local procedures

Safety issue details
Issue number: AO-2016-028-SI-01
Who it affects: Air transport ground handling
Status: Adequately addressed
General details
Date: 31 March 2016   Investigation status: Completed  
Time: 0051 EDT   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): Melbourne Airport    
State: Victoria   Occurrence type: Ground handling  
Release date: 13 September 2016   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Airbus  
Aircraft model A330-323  
Aircraft registration 9M-MTB  
Serial number 1219  
Operator Malaysia Airlines Berhad  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Minor  
Departure point Melbourne, Victoria  
Destination Kuala Lumpur, Malaysia  
Last update 16 September 2019