AO-1998-011

At about 2125 hours on Friday 4 December 1998, a loss of separation occurred between an Air New Zealand Boeing 767 and a Sunair Piper Aztec near Auckland Airport. Both aircraft were under radar control at the time of the incident. The Boeing 767, on departure from Auckland, was intercepting the Auckland - Rarotonga track and climbing to flight level 250. The Piper Aztec was en route from Hamilton to Whangarei via Auckland, maintaining 7000 feet. The pilot of the Piper Aztec saw the Boeing 767 closing from the left and descended to ensure separation. The aircraft passed within approximately 0.7 nautical miles horizontally and 900 feet vertically.

The controller, on clearing the B767 to turn right on to track, did not notice a possible conflict with the overflying Piper Aztec. The newly installed Short Term Conflict Alert facility alerted the controller to initiate collision avoidance action as the required separation requirements had been infringed.

The safety issues identified were:
• the difficulty for controllers to maintain situational awareness of overflying aircraft,
• controllers management of flight progress strips,
• the span of responsibility for controllers following the consolidation of air traffic control sectors,
• the interaction of the ground based Short Term Conflict Alert system and the airborne Traffic Alert and Collision Avoidance System, and
• interruption of a transmission by the controller to SAV 17R.

Five safety recommendations relating to the safety issues were made to Airways Corporation of New Zealand.