Loss of separation involving Boeing 747-400 and Bell 206B111, over Sydney, New South Wales, on 20 June 1992

The Boeing 747 (QFA 27) was cleared for take-off from runway 16 on a Mudgee One Standard Instrument Departure (SID). This SID procedure required the aircraft to track via the 163 radial of the Sydney VOR (omni) to 3,000 ft and then turn left to track back towards the airfield, passing overhead the Sydney VOR prior to setting course in a north-westerly direction.

The VOR navigational aid is located on Sydney Airport and the SID required the B747 to be at 5,000 ft or higher before passing the VOR. Sydney Air Traffic Control had cleared the aircraft to climb to its initial cruising level, flight level (FL) 310. The Bell 206 (VH-BHU) planned to climb overhead Sydney Airport to FL 125 for a photographic operation.

The Sydney Aerodrome Controller (ADC) cleared the helicopter to climb to FL 125 within the lateral confines of an area between Qantas Maintenance facilities, located on the airport and the Sydney Hilton Hotel which is about 0.5 km west of the airport's northern boundary. Due to suppression of radar returns within 3.5 km of the radar head, which is also located on the airport, the flight path of the helicopter was not detected on any ATC radar screen.