Incident Overview
On the afternoon of 28 September 2022, a Boeing 787-9, registered G-ZBKF and operated by British Airways as flight BA16, was cleared for takeoff from runway 16R at Sydney Airport, New South Wales. The flight was destined for Singapore. Shortly afterward, an Airbus A330-202, registered VH-EBK and operated by Qantas Airways as flight QF926, was also cleared for takeoff from the same runway, bound for Cairns, Queensland. Both aircraft were assigned the DEENA SEVEN standard instrument departure (SID) and instructed by the Departure controller to climb to flight level 280 via that SID.
Loss of Separation
During the departure, the following Airbus A330 climbed faster than the controller had anticipated. The A330 turned toward the next waypoint inside the preceding Boeing 787, resulting in a loss of separation between the two aircraft. The controller did not initially identify the variation in climb performance, in part due to focusing on other aircraft.
ATSB Findings
The Australian Transport Safety Bureau (ATSB) determined that the actual climb performance of the A330, on a domestic route with a lighter fuel load, was greater than that of the heavily loaded 787 on an international route. This performance difference was not expected or identified by the controller. Additionally, the design of the DEENA SEVEN SID did not provide a positive method for ensuring separation between aircraft with different performance characteristics. Because the procedure required aircraft to satisfy two separate conditions before turning, there was no way to guarantee that aircraft would turn at the same distance from the airport, meaning lateral separation could not be assured.
Response
Airservices Australia advised that the DEENA SEVEN SID has been redesigned to remove the conditional requirements of the procedure. The change was approved and planned to be released as part of the Western Sydney International (Nancy-Bird Walton) Airport project. At the time of reporting, a timeline for implementation was being developed.