What happened
During a departure from Sydney, a flight crew incorrectly programmed the flight management computer (F/MC) following a change in their assigned clearance. The pilot was originally expecting the SYD1 standard instrument departure but was instead issued the RIC5 departure, which included a radar transition procedure. While attempting to update the computer to reflect the new clearance, the pilot flying removed a discontinuity in the flight path. This discontinuity was intended to represent the radar vectors required to transition from the initial departure to the oceanic route. By deleting this gap, the aircraft was programmed to track directly toward waypoint DIPSO, causing the aircraft to turn right instead of following the prescribed path. This error ultimately led to a loss of separation between the aircraft and another flight.
The investigation
The investigation focused on the crew's departure setup and communication protocols. It was found that the pilot flying had limited experience with Sydney-specific departure procedures and was more accustomed to the procedural-based transitions used in the United States. The removal of the discontinuity was an error driven by a focus on resolving the coding gap in the F/MC.
Furthermore, the investigation examined crew coordination and communication. While the operator had established procedures for verifying F/MC accuracy, the pilot monitoring did not use the detailed LEGS page to verify the waypoint sequence, relying instead on the summary RTE page. Additionally, the pilot monitoring provided a truncated readback of the clearance to air traffic control, which was not challenged by the controller. This lack of a complete readback meant the controller had no assurance that the radar transition component of the clearance was understood.
Findings
- The pilot flying incorrectly amended the F/MC for the cleared departure.
- The amended setup was not effectively communicated by the pilot flying or cross-checked by the pilot monitoring or relief pilots.
- The pilot monitoring failed to perform a full readback of the radar transition segment of the clearance.
- The Sydney departures controller did not insist on a full readback of the clearance.