Executive summary
At about 1735 hours on Monday 2 June 1997 a loss of separation occurred between an RNZAF Hercules and an Eagle Air Metroliner proceeding in opposite directions on the Hamilton - Taumarunui track. The aircraft were under radar control and the Area Controller had cleared the northbound Hercules to descend from flight level 170 to 10 000 feet after the crew reported a pressurisation difficulty. The aircraft passed approximately 0.7 nm horizontally and 600 feet vertically apart.
No deficiencies were identified in relation to established standard procedures for radar control. However the incident underlined the safety benefit likely to ensue from the installation of a system software modification to provide an on-screen alert to controllers of an impending loss of separation and the importance of appropriate track and profile monitoring to ensure separation standards are maintained.
Related Recommendations
Without identifying individuals use the incident involving EAG 105 and HER 7002 in controller education and training as an example of unusual circumstances concerning a 'pressurisation' event, emphasising the importance of appropriate track and descent profile monitoring to ensure separation standards are maintained.
Assign appropriate priority to the installation of a system software modification STCA, already purchased, which will provide radar controller with an on-screen warning of an impending loss of separation between aircraft under radar control in the sectors for which they are responsible.