Breakdown of Separation - Boeing 767-300, Saab 340B, 19 km west-south-west of Sydney Airport, New South Wales, on 8 May 2007

On 8 May 2007 at about 1858 Eastern Standard Time, a Boeing Aircraft Company 767-338 (767), registered VH-OGI, was inbound to Sydney, NSW from Melbourne, Vic. on descent to 6,000 ft and a SAAB Aircraft Company 340B (SAAB), registered VH-OLL, was departing Sydney for Moruya, NSW on climb to FL140. The distance between the aircraft reduced to 1.5 NM horizontal and 400 ft vertical separation. Separation standards as specified in the Manual of Air Traffic Services (MATS) required the provision of either 3 NM horizontal or 1,000 ft vertical separation between the aircraft. There was a breakdown of separation.

The apparent distraction of the controller by his involvement in a non-operational control room discussion would probably have adversely affected his mental 'air picture' and traffic planning. That included unintentionally clearing the flight crew of the SAAB to climb through the assigned level of the inbound 767, rather than the routinely assigned intermediate altitude of 5,000 ft. The traffic manager's preoccupation with administrative duties meant that the monitoring and control of the distraction risk and operational activities in the control room was ineffective.

Action by the controllers to issue traffic information to the flight crew of the 767 and a radar vector and altitude limit to the flight crew of the SAAB quickly re-established the required separation standards.

Although no safety issue was identified as a result of this investigation, in its submission in response to the draft report, Airservices Australia (Airservices) advised of its development of an Air Traffic Control (ATC) Reform initiative. The aim of that initiative was to improve the structure and processes used by Airservices to verify ATC operational performance. At the time of writing this report, the initiative was in the design phase, with implementation planned for early 2009.