Loss of separation involving a Boeing 747, N188UA and Boeing 737-376, VH-TJD, 111 km east of Sydney Aerodrome, New South Wales, on 28 August 1995

The Sector 8 (Oceanic) controllers’ area of responsibility extended from 58 to 320 km east of Sydney. In the period preceding the incident, there was significant military traffic operating in the area above FL300.

VH-TJD was identified on radar 45 km NE of position LOTRA. (LOTRA is a reporting point 071 degrees M, 240 km from Sydney.) VH-TJD was then cleared to track from LOTRA to position CHEZA (084 degrees M, 96 km Sydney) and to descend to 8000 ft.

About 10 minutes later, N188UA departed Sydney. The standard procedure was for this aircraft to intercept the

Sydney-LOTRA track inside 50 km Sydney. On this occasion, however, the Sydney Departures controller asked the Sector 8 (Oceanic) controller if N188UA could track direct to LOTRA. The Sector 8O controller approved the request. As a result, N188UA was in potential conflict with VH-TJD.

At the time of the request from the Sydney Departures controller, the Sector 8 (Oceanic) controller had been distracted by a telephone call concerning a radar technical matter. He checked the radar display for conflicting traffic before agreeing to the request and did not see any confliction. At this time, however, the radar symbol for VH-TJD was amongst the military traffic radar symbols and was not noticed by the controller. The controller approved the request from Sydney Departures on this basis, and without checking the flight progress strips which displayed the flight details of all aircraft under his control at the time, including VH-TJD and the military traffic. In not checking the strips, the controller failed to comply with standard procedures, thus bypassing an element of the safety net which may have alerted him to the conflict.

As N188UA was climbing through about 15000 ft, the crew advised the Sector 8 (Oceanic) controller that they were deviating left as they had sighted descending traffic ahead. Examination of the recorded radar data showed the two aircraft to have been at the same level at 7nm (12 km) lateral separation.  The minimum separation standard which applied in the circumstances was 1000 ft vertical separation, or 5 nm (8km) lateral separation. The 1000 ft standard was infringed when the aircraft were between 8 km and 6 km apart.

AMENDED TEXT

The Sector 8 (Oceanic) controller's area of responsibility extended from 58 to 320 km east of Sydney. In the period preceding the incident, there was significant military traffic operating in the area above FL300.

The B737 was identified on radar 45 km NE of position LOTRA. (LOTRA is a reporting point 071 degrees M, 240 km from Sydney). It was then cleared to track from LOTRA to position CHEZA (084 degrees M, 96 km from Sydney) and to descend to 8,000 ft.

About 10 minutes later, the B747 departed Sydney. The standard procedure was for this aircraft to intercept the Sydney-LOTRA track inside 50 km Sydney. On this occasion, however, the Sydney Departures controller asked the Sector 8 (Oceanic) controller if the B747 could track direct to LOTRA. The Sector 8 controller approved the request. As a result, the outbound B747 was in potential conflict with the inbound B737.

At the time of the request from the Sydney Departures controller, the Sector 8 (Oceanic) controller had been distracted by a telephone call concerning a radar technical matter. He checked the radar display for conflicting traffic before agreeing to the request and did not see any confliction. At this time, however, the radar symbol for the B737 was amongst the military traffic radar symbols and was not noticed by the controller. The controller approved the request from Sydney Departures on this basis, and without checking the flight progress strips which displayed the flight details of all aircraft under his control at the time, including the B737 and the military traffic. In not checking the strips, the controller failed to comply with standard procedures, thus bypassing an element of the safety net which may have alerted him to the conflict.

As the B747 was climbing through about 15,000 ft, the crew advised the Sector 8 (Oceanic) controller that they were deviating left as they had sighted descending traffic ahead. Examination of the recorded radar data showed the two aircraft to have been at the same level at 7 NM (12 km) lateral separation.  The minimum separation standard which applied in the circumstances was 1,000 ft vertical separation, or 5 NM (8km) lateral separation. The 1,000 ft standard was infringed when the aircraft were between 8 km and 6 km apart.