Loss of separation involving a Aero Commander 500-S, VH-EXF and Cessna Aircraft Company U206G, VH-AHX, Darwin, NT on 13 September 1993

VH-EXF which had been operating on a low-level training exercise was cleared by Darwin Approach for a visual approach, and instructed to track to a left base for runway 36, and to contact the tower. The aircraft joined left base at about 800 feet AMSL and contacted the tower as instructed. After completing prelanding checks the pilot became aware of another aircraft on a converging track at a similar attitude. The separation between the aircraft was about 200 metres horizontally and less than 100 feet vertically. The other aircraft, VH-AHX, had just become airborne from runway 18 and was making a right turn, as instructed, onto a heading 240 degrees and climbing to 1000 feet.