Final Report


On 15 December 2016, an Airbus A330-202 aircraft, registered VH-EBA and operating Qantas Flight (QF) 652, was on descent to Brisbane Airport, Queensland, arriving from the south-west. QF652 was sequenced to follow another Qantas Airbus A330-303 aircraft, registered VH-QPG and operating QF62, which was also on descent to Brisbane Airport, but arriving from the north-west.

At 0516:25 Eastern Standard Time (EST), the approach controller cleared QF62 to descend to 5,000 ft.

At 0517:55, a Qantas Boeing 737-838 aircraft, registered VH-VXF and operating QF601, took off from runway 01 and was tracking to the south-west. At 0519:15, the approach controller cleared QF601 to climb to 8,000 ft.

Five seconds later, the approach controller cleared QF652 to descend to 9,000 ft for separation with QF601 travelling in the opposite direction.

At 0520:20, the controller inadvertently cleared QF652 (instead of QF62) to descend to 2,500 ft. The crew of QF652, still on descent to 9,000 ft, read back the clearance and set their assigned altitude to 2,500 ft.

About 30 seconds later, the air traffic system identified a discrepancy between the controller-cleared flight level of 9,000 ft and the flight crew-entered altitude of 2,500 ft. The controller received an alert and asked the crew of QF652 to confirm they were maintaining 9,000 ft. The crew responded that they were on descent to 2,500 ft as cleared. The controller immediately responded ‘no, that was for Qantas 62, Qantas 652 maintain 9,000’. The flight crew of QF652 reported that they were passing about 8,600 ft, when they received that instruction. The crew stopped the descent and climbed the aircraft back up to 9,000 ft.

The incorrect descent clearance resulted in a loss of separation with QF601, where the separation required was 3 NM or 1,000 ft and the minimum recorded was 2.5 NM and 700 ft.

The ATSB encourages aircraft operators to use call sign de-confliction strategies to help prevent similar incidents occurring. Air traffic control is encouraged to consider liaising further with airlines to enhance call sign de-confliction programmes.

Aviation Short Investigations Bulletin - Issue 59

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