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What happened

On 22 April 2013, the flight crew of a United Airlines Incorporated Boeing 747-422, registered N119UA, flew from Sydney, New South Wales to Melbourne, Victoria. At Melbourne, the crew taxied to gate D5 and stopped, applying the parking brake. Shortly after stopping, the aircraft started to move forward again slowly. The flight crew realised the aircraft was moving and re-applied the brakes. The aircraft’s left wing collided with the aerobridge before the movement had stopped. No one was injured during the occurrence and the aircraft sustained minor damage.

What the ATSB found

After stopping at the gate, the aircraft parking brake was likely inadvertently released before the nose wheels were chocked and the engines shut down. The flight crew’s attention was inside the cockpit, focused on shutting down the engines. As such they were not actively monitoring aircraft movement, nor was that required at this stage. In addition, the parking guidance system at the gate was set to emergency stop mode by ground personnel when the aircraft first arrived, removing the possibility of an alert for the flight crew that the aircraft had moved. The flight crew became aware of the movement when the captain detected motion through peripheral vision. The very slow acceleration, combined with a lack of visual cues available to the flight crew made it difficult for the crew to detect the movement in time to prevent the collision.

Safety message

This occurrence highlights the importance of flight crew remaining aware of the possibility of aircraft movement whenever the engines are running as aircraft movement, particularly if it is slow, is difficult to detect. Additionally, ground support crew are reminded of the need to leave the parking guidance system in normal mode, unless an emergency stop is required.

Boeing 747 N119UA

Boeing 747 N119UA

Source: Benedikt Mathweis

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Safety analysis


Sources and submissions


General details
Date: 22 April 2013 Investigation status: Completed 
Time: 1025 EST  
Location   (show map):Melbourne Airport Investigation type: Occurrence Investigation 
State: Victoria Occurrence type: Taxiing collision/near collision 
Release date: 07 July 2016 Occurrence class: Operational 
Report status: Final Occurrence category: Incident 
 Highest injury level: None 
Aircraft details
Aircraft manufacturer: The Boeing Company 
Aircraft model: 747 
Aircraft registration: N119UA 
Serial number: 28812/1207 
Operator: United Airlines 
Type of operation: Air Transport High Capacity 
Damage to aircraft: Minor 
Departure point:Sydney, NSW
Destination:Melbourne, Vic.
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Last update 14 November 2018