Qantas jets came within 15 metres from collision at Perth airport

Two Qantas jets came within 15m of colliding at Perth Airport after one ignored a stop signal and taxied on to a runway.

A Qantas 737 like those involved in the near collision in Perth. Picture: Dan Himbrechts/AAP

Two Qantas jets came within 15m of a collision at Perth Airport after one ignored a stop signal and taxied into the path of another preparing for takeoff.

The Australian Transport Safety Bureau has delivered its final report on the close call on April 28, 2018 involving two Boeing 737s.

The investigation found the captain of one of the aircraft had developed an “incorrect mental model” of the taxiways off runway 03, and did not think his plane would have to cross another runway.

Despite seeing an illuminated stop signal, the captain assumed it was incorrectly constructed and was meant for aircraft taxiing in the other direction.

As a result of his mindset, the other 737 on runway 06 was forced to abort its takeoff and veer to the left to avoid a collision.

The ATSB found the wingtip of the 737 on the runway passed about 15m from the other jet’s nose at low speed.

Diagram of two Qantas jets on a collision course at Perth Airport. Picture: ATSB

Aside from the captain’s assumptions, ATSB director of transport safety Mike Walker said the design of the taxiway in question increased the risk of a runway incursion.

“The relatively shallow intersection angle with the runway and wide turn radius meant pilots were more likely to take the exit at a higher speed, and this combined with the short distance to the holding point gave pilots less time to see the illuminated stop bar lights at the runway holding point and stop,” Dr Walker said.

In response to the incident, Airservices Australia made the taxiway unavailable for use, and Perth Airport subsequently took it off aerodrome charts.

Dr Walker said runway incursions were one of the most “significant risks to safe aviation operations” and were a key global safety priority.

“Airport operators and local runway safety teams are strongly encouraged to identify and mitigate the risk of hot spots, especially those that involve short distances between runways, complicated junctions, and the potential for higher taxi speeds,” said Dr Walker.

Since the incident, Qantas had published a safety information notice to all pilots containing information about the background of runway incursions.

The airline also updated its Flight Administration Manual to include a requirement for pilots to brief relevant airport hot spots in their contingency planning, to mitigate against the possibility of collision or runway incursion.

Qantas fleet safety captain Debbie Slade said they accepted the findings of the ATSB.

“As the pilots of the aircraft that was about to take off could see the other aircraft and was aware of its position on the taxiway, there was no danger that the aircraft would have come into contact,” said Captain Slade.

The investigation found Perth Airport had a significantly higher rate of runway incursion than other major airports in Australia with 11.6 incidents in every 100,000 aircraft movements compared to 2 for Sydney and 0.3 for Melbourne.

In the period from July 2015 to April 28, 2018, 44 such incidents were recorded in Perth, of which the Qantas 737 incident was the most serious.

Dr Walker said pilots could help prevent incursions by identifying runway hot spots during departure and approach briefings, and discussing the actions they would take to reduce the risk of a runway incursion.

“The ATSB also strongly encourages air traffic controllers to provide safety alerts and/or clear instructions – such as ‘stop immediately’ – to the flight crews of all aircraft involved in runway incursions and related occurrences,” he said.