Crew alertness avoids potential taxiing collision

The Australian Transport Safety Bureau (ATSB) reminds flight crews to remain alert and vigilant during taxiing, following an incident where a high workload situation probably led to an air traffic controller forgetting conflicting instructions had been issued.

Airport diagram showing aircraft track. Source: Airservices Australia modified by ATSB

During the 30 April 2018 incident, an Airbus A321 airliner was taxiing to the gate after landing at Melbourne Airport when the captain had to brake heavily to avoid a possible collision with a taxiing Boeing 737-800. Both aircraft had been given clearance by the surface movement controller in the control tower to proceed through the same taxiway intersection.

While the ATSB’s investigation found several factors had increased the workload of the surface movement controller, this occurrence highlights the importance of flight crews remaining alert and vigilant during all phases of their flight, including taxiing. Separation of taxiing aircraft is a joint pilot and controller responsibility, and the timely action taken by the captain of the Airbus helped to avoid a potential collision.

During the morning peak period, the surface movement controller, who was conducting on-the-job training with a trainee air traffic controller at the time, was in the process of handing over the position at the end of shift to a relieving controller.

... this occurrence highlights the importance of flight crews remaining alert and vigilant during all phases of their flight, including taxiing.

Additionally, taxiway maintenance work had resulted in some taxiway closures. While the works were not directly related to the clearances issued to the two aircraft involved in this occurrence, they did reduce the efficiency of controlling taxiing aircraft, thereby increasing the controller’s workload.

The ATSB’s investigation highlights how increased workload and distraction can reduce performance and increase errors. For air traffic controllers, using tools and practices that reduce reliance on memory and delaying handovers until lulls in activity can mitigate these effects.

Read the final report AO-2018-040: Taxiing proximity event involving Airbus A321, VH-VWQ, and Boeing 737, VH-VZB, Melbourne Airport, Victoria, on 30 April 2018

Last update 27 June 2019