Executive summary
On Monday 26 July 1999 at about 1250 hours, an Air New Zealand Boeing 737 was flying a circling instrument approach in the Queenstown Control Zone when a Mount Cook ATR 72 entered the zone without a clearance, infringing the separation requirements for the 2 aircraft.
The ATR 72 had descended early and was joining Queenstown under visual flight rules via Kawarau Gorge at low-level in poor weather. Before entering the gorge, the ATR 72 had been advised by air traffic control of a possible requirement to hold at a reporting point on the edge of the control zone. Committed to continue flying through the gorge in deteriorating weather, the ATR 72 was unable to hold at the reporting point when later instructed to. The crew of the ATR 72 had continued through the gorge in the belief that they did not need to obtain an entry clearance into the control zone.
Having entered the control zone the ATR 72 compromised the circling approach of the Boeing 737 that was operating in accordance with normal instrument flight rules procedures. The controller was initially unsure of the location and intended flight path of the Boeing 737, and when both aircraft were established in the zone he was left with little option than to position the ATR 72 in front of the Boeing 737. The captain of the Boeing 737 was then committed to continuing towards the aerodrome in reducing visibility because the ATR 72 had obstructed its primary escape route to the south of the aerodrome.
Safety issues identified were:
• the ATR 72 entering a control zone without an entry clearance
• safety procedures for flying through Kawarau Gorge
• a general poor industry understanding of the requirements for flight under special visual flight rules
• position reporting by aircraft after becoming visual on the instrument approach
• flight under visual flight rules by medium and large air transport aircraft
• poor industry understanding of the management of general aviation areas within the Queenstown Control Zone.
Recommendations were made to the operators of both aircraft, the Director of Civil Aviation and the Chief Executive of Airways Corporation to address the safety issues.
Related Recommendations
Submit for approval a rule change to special visual flight rules, in particular the application of the 1500 feet cloud ceiling, to remove any ambiguities that may exist.
Educate pilots on the operation of the use of general aviation areas, in particular those areas within the Queenstown control zone.
Educate pilots of the requirement to make a radio call when becoming visual on an instrument approach.
Educate pilots about the objectives and application of operations under special visual flight rules.
Approach the local air traffic service provider and local User Group to discuss the justification and acceptability of developing standardised procedures for the co-ordination of aircraft flying through Kawarau Gorge.
Review company procedures for flights through Kawarau Gorge, including the need for specified minimum flight altitudes and visibility requirements, which permit safe manoeuvring within the geographical constraints of the gorge.
Submit for approval a rule change for flight under visual flight rules in uncontrolled airspace by medium and large air transport aircraft, making reference to aircraft size and manoeuvrability, to ensure adequate safety margins are retained.
Review procedures to ensure air traffic service staff undergo proficiency assessments within the prescribed time frame.
Instruct company pilots of the requirement to obtain an entry clearance from the relevant controlling authority before entering controlled airspace.
Review procedures to ensure that if clearance to enter controlled airspace is not available then appropriate phraseology that correctly conveys that meaning is used, and that instructions requiring a specific action in uncontrolled airspace are not given by ATC.
Instruct Air New Zealand pilots of the requirement to make a radio call as soon as possible after becoming visual on an instrument approach and, if practicable, on circling approaches to include the aircraft's position and intended track to be flown.