What happened
During a visual approach into Sydney, the flight crew received a clearance that the captain noted as unusual. During the descent, the captain failed to select the necessary 500 ft altitude in the autopilot mode control panel. The first officer, acting as pilot monitoring, did not notice this omission. As the aircraft descended to 2,000 ft, the autopilot leveled off prematurely, causing the aircraft to deviate above the intended descent profile.
In an attempt to correct the path, the captain performed an unannounced manual intervention. This sudden change, occurring while the crew was managing final landing procedures, significantly increased workload and degraded the first officer's situational awareness. Due to these pressures and a lack of coordination, the crew missed critical checklist items, specifically the final flap and speed brake selections.
The investigation
The investigation focused on the failure to adhere to stabilized approach criteria. The aircraft did not reach the required landing configuration by 1,000 ft above the airport elevation. Although the captain believed the flap selection was timely, the flaps did not reach the necessary position until the aircraft was at 875 ft. While the first officer recognized that the configuration was late, they incorrectly announced the approach as 'stable' rather than declaring it 'not stable.'
Furthermore, the crew failed to notice that the speed brake landing procedure had been omitted. Although the descent rate briefly exceeded stabilized limits for 9 seconds, the primary issue was the failure to initiate a missed approach despite the late configuration and the unannounced manual flight intervention.