Australian investigators have detailed an incident in which a Cairns air traffic controller cancelled take-off clearance for a departing Tigerair Airbus A320 after realising it had lined up on the wrong intersection.
The crew – comprising of a trainee first officer and an instructing captain – inadvertently lined up at the B4 intersection of runway 33, rather than the B5 intersection which was some 400m further back.
Analysis by the carrier showed that the aircraft would have overrun in the event of a take-off abort, states the Australian Transport Safety Bureau in its assessment of the 21 January event.
Although the A320 crew had been cleared to taxi – and had carried out take-off calculations – for a B5 intersection departure, investigators believe the first officer, who was taxiing the jet, "may have been distracted" by a preceding turboprop, and unconsciously followed it.
The turboprop had been cleared to the B4 intersection.
"There was no specific instruction to the flight crew of [the A320] to follow the [turboprop]," says the inquiry. It adds that the captain was communicating with cabin crew at monitoring the cabin video as the A320 turned towards the intersection, reducing the chance of the error being detected.
Investigators state that the controller cleared the A320 for take-off and the captain read back the clearance. But the controller then "immediately" informed the crew that they were wrongly lined up at the B4 intersection, says the inquiry.
"The crew did not respond so the [controller] cancelled the take-off clearance and instructed them to hold position," it adds. The jet subsequently taxied to the correct intersection and departed without further incident.
Investigators state that the crew procedure for checking the departure runway did not include a requirement to reference the intersection.
Tigerair has distributed a flight training notice to highlight the incident to A320 and Boeing 737 crews.