What happened
During ground operations, the surface movement controller (SMC) issued taxi instructions to the crew of RXA2113 that directed them to runway 06. This instruction contradicted the air traffic system's records, which had assigned the aircraft to runway 03. The flight crew followed the instructions to hold point V, runway 06. Despite noticing a discrepancy between the instructions and the ATIS information, the crew did not request confirmation, missing an opportunity to rectify the error.
Subsequently, a trainee aerodrome controller (ADC) issued a take-off clearance for RXA2113 from runway 06. This clearance was also inconsistent with the departure runway recorded in the flight data record. Because the aircraft departed from runway 06, its initial flight track differed from the northward path expected by the departures controller, potentially impacting that controller's situational awareness.
The investigation
The ATSB examined the actions of the SMC and the ADCs to determine why the incorrect runway was used. Regarding the SMC, investigators found that the flight data record was clear, legible, and highly visible, suggesting the controller likely failed to attend to the record when issuing the taxi clearance. There was no evidence of fatigue, stress, or workload issues contributing to this oversight.
For the ADC function, the investigation focused on whether the ongoing training activity influenced the error. The ATSB found that the training itself was likely not a factor. Instead, the controllers were focused on monitoring traffic and runway safety. The physical position of RXA2113 at hold point V created a strong expectation that the aircraft was scheduled for runway 06, leading the controllers to either overlook or misperceive the actual flight strip data.
Findings
- The primary cause of the incorrect taxi was the SMC's failure to verify the flight data record.
- Expectation bias played a significant role, as the aircraft's position at hold point V reinforced the controllers' incorrect assumption that runway 06 was the correct departure runway.
- The flight crew's failure to highlight the discrepancy between the taxi instructions and the ATIS prevented an early resolution of the error.
- The incident did not result in a reduction of safety for the aircraft or other traffic, and no broader safety risk was identified.