Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (ATSB) to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation.

On 24 October 2014, the ATSB commenced an investigation into a loss of separation assurance involving an Embraer EMB-135, registered VH-JTG, and an Airbus A321, registered VH-VWX, overhead Taroom Aerodrome, Queensland on 21 October 2014.

Examination of the information collected during the investigation indicated that the aircraft were assigned the same flight level on crossing tracks resulting in a loss of separation assurance. VH-JTG passed in front of VH-VWX and separation reduced to 6.6 NM (12 km). The lateral separation standard at the time was 5 NM (9 km) and there was no Short Term Conflict Alert (STCA) or other alert issued, including by the aircraft’s systems.

The ATSB did not identify any organisational or systemic issues that contributed to the incident and assessed that no safety issues would be identified through further investigation. On that basis, the ATSB has decided to discontinue its investigation.