What happened
On May 6, 2022, two Qatar Airways flights, A7-BAC (a Boeing 777-300) and A7-BAH (a Boeing 777-300ER), were operating within the Colombo Oceanic Control Area. The aircraft were traveling westbound on route N640, passing the ELATI position.
At approximately 20:22 UTC, the pilot of A7-BAC requested a climb from flight level 300 to 340. The ADS Controller granted this clearance. However, the clearance was issued while A7-BAH was maintaining flight level 320, resulting in a breach of the required 50NM longitudinal separation. Following the error, the controllers attempted to rectify the situation by sending messages to the aircraft, though the instructions were not properly communicated to the climbing aircraft.
The investigation
The investigation, conducted by the Civil Aviation Authority of Sri Lanka, examined the actions of the two air traffic controllers on duty. The inquiry focused on the handover process between the outgoing and incoming Executive Controller, the division of responsance between the Executive and ADS Controllers, and the use of the Air Traffic Management (ATM) system. The investigation also looked into the duty rosters and the fatigue levels of the personnel involved, as well as the failure of the controllers and management to report the incident through the mandatory occurrence reporting system.
Findings
- The primary cause of the incident was the failure to observe fundamental air traffic control procedures by verifying traffic conditions before authorizing a level change.
- The controllers were experiencing fatigue due to excessive duty hours and long shifts.
- There was a lack of clearly defined responsibilities between the Executive Controller and the ADS Controller.
- The controllers failed to utilize available safety features and decision-support tools within the ATM system, such as the flight progress strip board.
- The sector capacity was high during a peak traffic period, yet the controllers failed to implement necessary sectorization.
- There was a significant failure in the safety culture, as the incident was not reported to the senior management or the regulatory authority by the duty controllers.