Qantas 737s close call leads to ATC changes at Sydney Airport

A close call involving two Qantas 737s over Sydney has led to Airservices undertaking no less than six safety actions.

A 12-second delay in relaying important air traffic control information to a Qantas 737 flight, contributed to a close call over Sydney involving a second 737, the Australian Transport Safety Bureau has found.

The final report on the “separation occurrence” at Sydney Airport revealed half a dozen safety actions had been adopted by Airservices Australia, to prevent a repeat event.

On the evening of April 29, 2023, one Qantas 737 bound for Brisbane was cleared for takeoff, as another Qantas 737 arriving from Auckland approached the same runway for landing.

There were 58 people on the Brisbane flight, and 107 on the service arriving from New Zealand.

Shortly after the departing aircraft began its takeoff roll, the air traffic controller realised the incoming flight was too close behind to be assured of a safe landing.

As the controller went to direct the flight to go around, the tower shift manager told them to “wait” and instead the pilot was instructed to continue the approach to land.

With no further communication from the manager, the controller delivered the go around instruction 12-seconds later, and the 737 began to increase its altitude from 450ft.

The ATSB report said the lost time meant the incoming flight was 160ft lower and almost a kilometre closer to the runway threshold by the time the go-around order was finally issued.

It was then a second problem arose, when the controller directed the flight to turn left at 2100-feet.

The direction was interpreted as overriding the standard missed approach procedure of turning left at 600ft, which resulted in the two 737s passing within 1.5km horizontally and 330ft (100m) vertically.

“The timing of the additional instruction likely added to the pilots’ workload compared with letting the crew undertake the go‑around manoeuvre, and the turn at 600ft, before issuing any further turn instructions,” the ATSB said.

With the two aircraft uncomfortably close, air traffic control issued a safety alert and guided one 737 away from the other.

A Qantas 737 taking off from Sydney’s Kingsford Smith Airport. Picture: David Gray/AFP

ATSB director of transport safety Stuart Godley said in complex airspace settings it was “inevitable errors would sometimes be made by controllers and pilots alike”.

“Consequently, the system within which these activities take place should be designed to be resilient to error and to reduce the impact that individual actions can have on the overall safety of operations,” he said.

Dr Godley said Airservices had advised it had undertaken, and would continue to undertake, a range of safety actions.

“These include a detailed analysis of landing runway occupancy times at Sydney, and possibly other major airports, to determine expected runway occupancy times for different types of aircraft and conditions,” he said.

The Sydney tower would also add “defensive controlling techniques and minimum assignable altitudes” to go around scenarios, particularly at night.

An Airservices Australia spokesman declined to comment on the report, pointing to the safety actions already being undertaken by the air traffic management agency.

A Qantas spokesperson said their pilots had followed ATC instructions at all times.