- Cessna Caravan took off from Ballina Airport directly towards an approaching Boeing 737;
- Caravan pilot had an incorrect mental model of the traffic situation;
- B737 flight crew did not hear radio calls from the Caravan until the Caravan had commenced entering the runway;
- The SFIS controller did not issue a safety alert as they were concerned that doing so would result in over transmitting communications between the B737 and Caravan.
A Cessna Caravan pilot's incorrect mental model was one of number of contributing factors that led to their aircraft taking off from Ballina Airport directly towards a Boeing 737 airliner that was on approach to land there, an Australian Transport Safety Bureau investigation details.
The incident occurred on the afternoon of 16 September 2021, when a Virgin Australia 737-800 was conducting a scheduled passenger service from Sydney to Ballina, and the Caravan was commencing a repositioning flight from Ballina to the Sunshine Coast. The Caravan had commenced its take-off roll from Ballina's runway 06 to the east when the B737 was on final approach to land on the reciprocal runway 24 from the west.
The Caravan pilot's radio call on the Ballina CTAF (common traffic advisory frequency - a designated radio frequency pilots use to make positional broadcasts in the vicinity of airports where there is no air traffic control tower and separation service) announcing they were entering the runway and commencing their take-off roll, was the first call the 737's crew recalled hearing from the Caravan.
Neither the Caravan pilot, nor the surveillance flight information service (SFIS) controller - an air traffic controller based in Brisbane Centre who provided traffic information to aircraft operating in the Ballina CTAF - recalled hearing the 737 crew's subsequent broadcast on the CTAF that they were on a 5 NM final approach.
In subsequent radio calls the crews of the two aircraft established communications with each other, with the Caravan pilot confirming they could see the B737, and the B737 requesting the Caravan commence a turn.
The Caravan pilot initiated a turn to the right shortly after becoming airborne, while the 737 crew commenced a missed approach (aborting the landing).
Shortly after, the 737 flight crew then sighted the Caravan ahead of their aircraft, flying in a northerly direction. They then received a traffic collision avoidance system (TCAS) traffic advisory generated by the Caravan's proximity.
