What Happened
On the afternoon of 16 September 2021, a Boeing 737-8FE aircraft, registered VH-YIO, operated by Virgin Australia Airlines, was on a scheduled passenger flight from Sydney Airport, New South Wales, to Ballina Byron Gateway Airport (Ballina Airport). Simultaneously, a Cessna Caravan 208, registered VH-YMV, was taxiing for a private instrument flight rules flight from Ballina Airport to Sunshine Coast Airport, Queensland. As the B737 was on final approach to land on runway 24, the Caravan taxied onto the runway and began a take-off roll towards the approaching B737. The flight crew of the B737 conducted a missed approach to avoid the Caravan, during which they received a traffic collision avoidance system traffic advisory. At the closest point, lateral separation decreased to approximately 0.9 nautical miles and vertical separation to about 700 feet. Both aircraft were operating within the airport's broadcast area and were receiving a surveillance flight information service (SFIS).
Findings
The Australian Transport Safety Bureau (ATSB) investigation identified that the Caravan pilot had an incorrect mental model of the traffic scenario, believing the B737 would land behind them on runway 06 rather than runway 24. The SFIS controller had provided traffic information to the Caravan pilot but did not specify the landing direction of the B737, and the pilot did not seek this information. The situation was compounded by the B737 flight crew not hearing the initial communications from the Caravan pilot or the SFIS controller's response; they remained unaware of the Caravan until just before it entered the runway. The Caravan pilot did not see the B737 approaching from the opposite direction and took off directly towards it. No safety alert was issued by the SFIS controller due to concerns about over transmitting communications from the aircraft in conflict. The ATSB also found that the SFIS had been implemented in an area with known surveillance coverage limitations, resulting in the controller having no displayed positional information for the Caravan until it reached an altitude of about 1,500 feet. Consequently, the controller relied solely on radio communications for situation awareness during the period of conflict.
Safety Actions
Airservices Australia advised that there was an intention to install additional technology to improve surveillance coverage near Ballina Airport by March 2023, though the timeline was dependent on several factors. The ATSB issued a safety recommendation to Airservices to address this surveillance limitation in a timely manner, noting the indefinite timeframe and supporting a related recommendation from the Civil Aviation Safety Authority. The ATSB also emphasized the importance of pilots communicating directly on the common traffic advisory frequency when SFIS is provided, and that critical information should be confirmed to maintain accurate shared mental models. Additionally, the ATSB strongly encourages the fitment of ADS-B transmitting, receiving, and display devices for enhanced traffic awareness.