Breakdown of separation, VH-TQZ, Tamworth Aerodrome, New South Wales, on 7 February 2008

On 7 February 2008 at Tamworth Aerodrome, New South Wales, an air traffic controller issued a take-off clearance to the flight crew of a Bombardier Inc DHC-8-315 (DHC8) aircraft, registered VH-TQZ, for runway 30 Right. At the same time, an airport operations officer was operating a vehicle on that runway.

The controller had previously issued a clearance to the operations officer to conduct bird dispersal activities on the runway. The operations officer was monitoring his radio and heard the DHC8's take-off clearance. He advised the controller that he would vacate the runway. At the same time, the flight crew had observed the vehicle on the runway and did not commence the takeoff. The controller cancelled the take-off clearance until the runway was clear.

While these secondary safety defences effectively prevented any possibility of an accident, the issue of the take-off clearance with the vehicle on the runway constituted a breakdown of separation.

The investigation found that the controller's scan of the runway and flight strip board was not effective as a result of his pre-occupation with the management of current and pending traffic and the associated high volume of radio communications. It was also possible that the controller was experiencing some degree of fatigue at the time. The ATSB's investigation did not detect any safety issues that required consequent safety action.