Virgin Australia changed its operating procedures for aircraft pushing back from selected gates at Melbourne Tullamarine after an on-the-ground collision with a nearby Jetstar Airbus A320 in 2013, the Australian Transport Safety Bureau (ATSB) says.
The incident, which occurred on August 10 2013, happened when the left wingtip of a Virgin Boeing 737-800 VH-YID pushing back for departure hit the tail cone of a Jetstar A320 VH-VGR that had just arrived from Sydney and was holding short of its gate.
The ATSB’s final report on the incident, published on Thursday, said the ground controller had issued pushback approval to the Virgin 737 located at gate E1 that required the Jetstar A320 to be on gate D2 before pushback could commence.
The Jetstar Airbus ended up stopping short of gate D2 after the automatic nose-in guidance system (NIGS) displayed a “STOP-WAIT” message.
The crew then transmitted to the controller that they were holding short of the gate because of the NIGS, the ATSB report said, then repeated the message about 40 seconds later because the first message had been “over-transmitted by another aircraft”.
“The message was acknowledged by the controller, who requested to be advised when the aircraft was at the gate,” the report said.
As a result, the Jetstar aircraft was not in position before the Virgin aircraft commenced its pushback.
However, the ATSB report said the dispatcher of the Virgin 737 looked under the aircraft and saw that the Jetstar A320 had stopped, then waited for 15-20 seconds “to confirm the aircraft remained stationary”.
“While VGR was actually holding short of the gate, the dispatcher formed the opinion that the aircraft was on the gate based on the observation that it had been stationary for a period of time,” the ATSB said.
“This was consistent with their experience and as a result, they did not move to a position from where they could accurately assess VGR’s location.
“The pushback of the B737 was commenced with insufficient clearance from the A320, which was not identified prior to the collision as the dispatcher’s position to the right-front of the B737 prevented observation of its left wing.”
The left wingtip of the Virgin 737 contacted the tail cone of the Jetstar A320 immediately aft of the operating auxiliary power unit. The tail cone fell to the ground.
While the ATSB report noted that from dispatcher’s perspective, the Virgin 737 obscured most of the Jetstar A320, it was normal practice for Virgin not to use a wing walker during pushback from gate E1.
“Following this occurrence, Virgin Australia Airlines Pty Ltd provided a local instruction to Melbourne Airport ground staff that stipulated the gates that required the presence of a wing walker prior to push back,” the ATSB said.
“Gate E1 was included in that list of gates.”
In terms of the radio communications between the flight crew of the Jetstar A320 and the ground controller, the ATSB said it was “not reasonable to expect that the transmission from VGR could have alerted the crew of YID to the collision risk”.
“In addition, in the lead up to the collision, the crew of VGR were communicating with their company to resolve the issue with the nose-in guidance system at the gate. This limited their ability to identify and therefore react to the collision risk.”
There were no injuries resulting from the incident.