Loss of separation assurance involving a Boeing 717-200, VH-NXQ and Boeing 777-312ER, 9V-SYI, 303 km N Perth Airport, WA, 25 October 2012

Two aircraft, both maintaining flight level 350, were on converging tracks with the same estimate for overhead Morawa NDB, Western Australia. A controller noticed the potential conflict and alerted the sector controllers managing the flights, who acted to resolve the situation.  There was a loss of separation assurance. 

Discontinuation:

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 26 October 2012, the ATSB commenced an investigation into an airspace event involving a Boeing 717-200 aircraft, registered VH-NXQ, and a Boeing 777-312ER aircraft, registered 9V-SYI, near the Morawa non-directional radio beacon, Western Australia, on 25 October 2012.

Examination of the information collected during the investigation indicated that although there was a loss of separation assurance, the potential conflict between the two aircraft was detected and actively managed by air traffic control. This ensured that the required separation standard was maintained.

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