What happened
On the night of 5 August 2019, a loss of separation occurred at Sydney Airport involving an Airbus A330 and a Boeing 737. The incident began during runway operations on runway 34R, where a trainee aerodrome controller and an on-the-job supervisor were managing arrivals and departures.
Following the landing of a Dash 8, the trainee controller cleared the Airbus A330 to line up and take off while the Boeing 737 was on final approach. Realising that adequate runway separation could not be maintained, the trainee controller instructed the Boeing 737 to perform a missed approach. During the subsequent turn to the right, the Boeing 737 came into close proximity with the climbing Airbus A330.
The investigation
The investigation revealed that the Boeing 737 flight crew had operated at speeds higher than specified for the independent visual approach and failed to notify air traffic control of this deviation. This increased speed, combined with the slower performance of the preceding Dash 8, reduced the available spacing.
Furthermore, the approach controller had transferred the Boeing 737 to the tower without the required coordination, and the spacing between the arriving aircraft had dropped below the 5 NM standard. The trainee controller's ability to judge the separation was compromised by these factors. Additionally, the Boeing 737 crew did not initiate their turn at the mandatory 600 ft altitude, continuing on a heading that brought them closer to the departure path of the Airbus A330.
Findings
- The Boeing 737 crew did not adhere to approach speed limits or communicate speed non-compliance to ATC.
- Inadequate coordination between the approach and aerodrome controllers allowed aircraft to be sequenced with less than the required 5 NM separation.
- The trainee controller's assessment of separation was hindered by an incomplete understanding of the aircraft speed differences.
- The Airbus A330 was cleared for immediate takeoff without sufficient buffer to prevent a separation loss.
- The Boeing 737 crew delayed their turn beyond the missed approach point, increasing the risk of collision.
- The on-the-job instructor's prompts to the trainee controller were insufficient in scale to address the criticality of the situation.
- Airservices Australia had not formally identified or managed the specific risk of concurrent standard instrument departures and missed approaches on runway 34R.