A terrifying close call between two passenger planes above Sydney airport took place after directions from the control centre were misheard, an investigation has found.
A Singapore Airlines flight was preparing to land in Sydney on February 9, 2020 but bad weather left the pilots of the Airbus A380 unable to land on the first attempt.
The crew advised Sydney Airport air traffic control of the missed approach and were told to turn right onto a heading of 270°.
They read back the heading, however, did not include the direction of the turn.
"Air traffic control did not correct the incomplete readback and the flight crew commenced turning the aircraft left instead of right," investigators at the Australian Transport Safety Bureau said.
The aircraft was then on a path that would take it very close to another passenger plane and was ordered to turn right and immediately climb.
The second passenger plane was also told to turn right to maintain the necessary separation between the aircraft.
However that order then left the second plane flying too close to a third passenger plane.
The Australian Transport Safety Bureau said the incident could have been avoided if air traffic control had responded differently.
"The ATSB found that the flight crew were likely experiencing high workload as a result of conducting the windshear recovery and published missed approach procedure," it said.
"This, in combination with an expectation that they would be turning left, contributed to them mishearing the ATC instruction to turn right.
"As a result, the aircraft was turned left. In addition, the flight crew omitted information from their readback and ATC did not correct the flight crew's incomplete readback, which was a missed opportunity to correct the misheard instruction.
"This incident highlights the importance of flight crew completing full readbacks, as well as controllers correcting any readback discrepancies immediately."