Breakdown of separation, 17 km west of Melbourne Airport, Victoria

On 29 May 2006 at about 0805 Eastern Standard Time, a Boeing Company 737-7Q8 aircraft (737) passed within 400 ft vertically of an Aero Commander 680-FL (Aero Commander) aircraft. At that time there was less than the minimum 3 NM radar separation standard or the 1,000 ft vertical separation standard between the two aircraft.

The 737 departed Melbourne Airport tracking to the north and then to the north-east of Melbourne on a runway 27 DOSEL 3 standard instrument departure (SID). The Aero Commander became airborne off runway 35 at Essendon. The pilot of the Aero Commander was instructed to track overhead Melbourne Airport and climb to 3,000 ft. From overhead Melbourne Airport, the pilot was instructed to fly a heading of 310 degrees magnetic.

The pilot of the Aero Commander advised the departures controller that he had the 737 in sight. However, there was a breakdown of separation standards because the departures controller did not comply with the requirements of the Manual of Air Traffic Services (MATS) when he assigned separation responsibility to the pilot of the Aero Commander.