Loss of separation involving an Israel Aircraft Industries 1124, VH-LLY and Israel Aircraft Industries 1124, VH-JPW, 18 km west of Darwin Aerodrome, Northern Territory, on 31 October 1994

The pilot of VH-LLY was cleared for descent in Darwin controlled airspace from FL330 to 5,000 ft, on a heading of 085, for radar vectoring to the ILS. VH-JPW had departed Darwin, and the pilot was cleared for climb to FL330, on a heading of 163.

During descent, as VH-LLY was passing through 8,000 ft with a 3,000 ft per minute rate of descent, the pilot heard Darwin Approach advise the pilot of VH-JPW of unidentified traffic in his 2 o'clock position, and to maintain 6,000 ft until clear. He looked out and sighted another aircraft rapidly approaching and realised that he must be the unidentified traffic. He resumed control from the co-pilot, made an immediate left turn and passed behind the other aircraft, with an estimated separation distance of 200m.

He then contacted the pilot of VH-JPW and Darwin Approach to advise them of the occurrence. The pilot of VH-JPW believed that if he had not maintained climb power when he levelled at 6,000ft, the passing distance would have probably been much less.

The Darwin Approach Controller admitted to misidentifying VH-LLY, contributing to the breakdown in separation standard.