Southern Star

The lack of an instrument approach procedure resulted in the airport being prone to weather disruption, while visual operations required that the airport be available only during daylight hours.

Airways New Zealand commissioned a VOR/DME in 1991, allowing Air New Zealand to begin jet operations soon after.

Nonetheless, the instrument approach procedures enabled by the VOR/DME still required aircraft to undertake a visual breakout procedure and descend visually.

In order to improve service reliability, Qantas and Air New Zealand pioneered the introduction of RNP-AR (required navigation performance authorisation required) procedures into Queenstown. RNP-AR approach procedures enable aircraft to accurately determine their position and descend along Lake Wakatipu to land. They have enabled aircraft to land with a cloud ceiling of 400ft AGL. GE Naverus commercially developed these procedures in conjunction with Airways. While RNP-AR procedures established lower minima for jet operations, pilots commonly had difficulty in locating the runway in poor weather conditions. To address this problem, basic runway lighting for daytime operations was introduced in 2011. This operational configuration of RNP-AR procedures and runway lighting is termed enhanced daylight operations. The New Zealand Civil Aviation Authority (NZCAA) did not support night operations.

A fleet mix comprising jet and turboprop aircraft has presented Air New Zealand with a number of challenges introducing RNP-AR capability. Air New Zealand was the lead customer in having Airbus develop RNP-AR capability for its A320 aircraft, but its ATR 72 fleet (operated for Air New Zealand Link by Mount Cook Airline) is not equipped to operate RNP-AR as ATR has not developed the required avionics for the type. Industry sources indicate that while ATR is in the process of developing RNP-AR capability for the ATR 72 it is likely to take a few more years before this occurs. In the meantime, Air New Zealand’s ATR 72-600 fleet will continue to rely on the VOR/DME aid or GNSS approaches.

“Aircraft relying on VOR/DME or GNSS are weather-disrupted around 15-20 per cent of the time. In comparison, approximately 95 per cent of aircraft operating under RNP-AR are able to land. This enables airlines to now provide a high level of service reliability all year round,” notes Clayton Lightfoot, Airways New Zealand’s Queenstown chief controller.

The introduction of RNP-AR, with jet aircraft descending to low levels on routes operated by VFR aircraft, provided the imperative forAirways to introduce multilateration surveillance for the Queenstown area. Multilateration involves triangulating aircraft transponder signals to determine aircraft height and position. Transponder signals are collected from a network of 14 sites around the Queenstown area. Unlike traditional radar, which requires a direct line from the antenna to the aircraft, multilateration is ideally suited to mountainous areas.

This multilateration system is not used for separation purposes. Instead air traffic controllers use surveillance information to provide situational awareness in order to assist pilots to see and avoid each other in Class D airspace. With air traffic controllers being able to observe the progress of flights, radio frequency congestion is reduced.

A high level of service resilience for jet operations has provided the foundation for significant passenger growth. For the financial year 2013/14, Queenstown recorded a 4. 2 per cent increase in passenger movements compared to the previous year. This passenger growth was attributable to an increase of 28 per cent in international trans-Tasman numbers. However, domestic passenger numbers fell slightly by two per cent, although the Auckland route continued to grow by five per cent.

The number of fixed-wing and helicopter landings increased by seven per cent, while private jet landings grew by 14 per cent. On the other hand, scheduled airline landings showed a slight drop of one per cent.

Scott Paterson, CEO Queenstown Airport Corporation (QAC) provides further explanation: “For the past 12 months international passengers comprised 25 per cent of the total

We can have 60 IFR flights between 10am and 5pm. When there is a flight disruption airport infrastructure struggles to cater for this number. CLAYTON LIGHTFOOT

IFR and VFR aircraft want to be in the same tube of airspace. CLAYTON LIGHTFOOT

volume. Winter is the peak time for international passengers. By way of illustration, in July 2014 41 per cent of Queenstown passengers were from international flights. In March 2014 the proportion of international passengers was only 21 per cent. Comparing passenger numbers in July 2013 with July 2014 shows an increase of 28 per cent.

“Most international growth (57 per cent) occurred on the Brisbane route. This route had suffered from under-capacity but during the past 18 months both Virgin and Air New Zealand have added capacity. Sydney and Melbourne routes still achieved double-digit growth, although these routes already had greater seating capacity than Brisbane. ” Adds Paterson: “Domestic passenger numbers peak during the summer. The drop in scheduled arrivals is due to Jetstar ending its Wellington to Queenstown direct service. The spare aircraft capacity has been redirected to trans-Tasman routes. We have also seen the replacement of 737 by the higher seat capacity A320 aircraft. Although the number of aircraft movements has fallen slightly, the number of seats available has increased. ” ATR 72 turboprop aircraft provide services on the Wellington and Christchurch routes. The end of the Jetstar service from Wellington has meant that Air New Zealand is the sole operator to Queenstown on these two routes. A loss of competition has resulted in relatively high fares.

Says Paterson: “The smaller capacity ATR 72 provides for greater frequency of services but these aircraft are vulnerable to weather disruption and diversion through not being RNP-AR-equipped. Unfortunately many passengers, particularly business travellers, are unwilling to set firm travel plans that rely on these services. ”Plans are underway to provide noise mitigation for 380 homes. The requirement for daylight operations constrains the span of time when aircraft operations can take place. During the middle of winter the airport operating window is between 8. 20am and 5. 05pm. Often this period is shorter due to the need to allow ice to thaw before morning flights can commence.

“We can have 60 IFR flights between 10am and 5pm. When there is a flight disruption airport infrastructure struggles to cater for this number,” Clayton Lightfoot explains.

Adds Paterson: “QAC has progressively added capacity to the terminal building. We have recently completed a refurbishment of the terminal retail space. This winter we used temporary facilities to handle the passenger volume. Work will start during September to expand international facilities within the terminal. We are also working on a project to improve passenger check-in, which involves providing kiosk facilities and new bag drop arrangements.

“The concentration of flights during a small window means that we risk being caught in a never-ending spiral of adding terminal capacity every two or so years. Improved utilisation of the existing infrastructure requires that aircraft operations are able to take place up to 10pm. This involves night operations during winter months. ” Evening/night operations also provide greater access to Queenstown by business and leisure travellers from both Australia and within New Zealand. “At present, flights need to depart Auckland and Wellington in the early afternoon during winter to complete a turnaround at Queenstown prior to 5pm,” Paterson says. “Flights from Australia need to depart by mid-morning. With night operations flights can depart after 5pm from Auckland and mid-afternoon from Australia. A greater window for operations provides the platform forpassenger growth. Early and late flights also open Queenstown as a home location for business travellers. ” Jetstar and Air New Zealand had independently performed risk assessments for night operations at Queenstown since 2008. In 2012 the NZ CAA completed a risk analysis of operations at Queenstown. It concluded that night operations were well above tolerable risk levels unless a significant infrastructure upgrade was undertaken.

QAC then promoted a coordinated and structured industry approach to understand the risk and feasibility of night operations. The outcome was a foundation safety case that defined the various elements provided by each operational stakeholder plus the initiatives required to enable night operations. Auckland-based Navigatus Consulting was engaged to facilitate this process, which was termed Project Twilight.

QAC, Qantas, Jetstar, Air New Zealand and Airways were involved in the process to develop the foundation safety case. It involved background research and analysis by Navigatus, three stakeholder workshops plus further analysis by the airlines and Airways. The integrity of the process required that the organisations set aside ‘pet’ issues and hold no predetermined view of what the risks and their mitigations might be. Commercial considerations were firmly out of scope.

NZCAA and Australia’s CASA were briefed about progress of the development of the safety case. CASA was included to ensure that the Australian-based airlines would achieve approval to operate.

Analysis spanned the various arrival and departure phases plus system elements, eg ATC operations, flightcrew procedures, infrastructure, aircraft performance, operating conditions etc. It involved defining and analysing threats, mitigations and responses. Probability analysiswas used to link threats, events and consequences.

The safety case proposed widening the runway to 45m and implementing a new lighting system. This lighting system includes dual PAPI; truncated approach, centerline and touchdown zone lights; and obstacle lights on nearby hills. Other initiatives included enhanced fire and rescue capability, particularly for water; enhanced pilot briefing; and improved weather and condition reports.

Airlines brought in experienced Queenstown pilots, from both line and managerial roles. The process looked at individual risks and mitigations. It involved drilling down into the various risk categories and assessing how they could be successfully mitigated. Airline representatives commented that it was not possible to manipulate the outcome of the risk assessment.

The safety case provides for night operations by A320s and 737-800s utilising RNP-AR procedures. It enables operators to retain independent operating philosophies and aircraft equipage plans. A number of airlines consider that aircraft undertaking night arrivals should be equipped with head-up display (HUD). While not mandating use of a HUD, both regulators have recognised the benefits of HUD as a component of the operator safety case.

Each airline is required to develop an operator safety case for approval by its regulator. The operator safety case will define operating parameters such as maximum cross-wind. Depending on the specific features of the safety case the approach minima could reduce from 400ft to 250ft AGL. Airport infrastructure improvements will be completed in 2015/16.

Another outcome arising from the 2012 NZCAA review of Queenstown was a recommendation to commence consultation with users on whether to change the airspace classification to Class C. At present Queenstown has a Class D airspace classification. Class D requires that IFR aircraft are separated by air traffic control but IFR and VFR aircraft are not separated from each other.

Queenstown has significant tourist flights travelling to and from Milford Sound, as Lightfoot explains. “Flights to Milford Sound typically use three low-level routes to enter and vacate the Queenstown area. These routes take the aircraft up the Frankton arm then to the northern part of Lake Wakatipu. However, this is the area where IFR aircraft are descending on a RNP-AR approach. This means that IFR and VFR aircraft want to be in the same tube of airspace. The concern is that jet aircraft might be able to sight VFR aircraft but cannot avoid the traffic due to the high terrain. The navigation tolerances of aircraft flying a RNP-AR require that they closely follow the defined flight path detailed. Air traffic control is able to manage this conflict by keeping VFR aircraft below the IFR or laterally off to one side. The multilateration surveillance system enables us to accurately determine the position of aircraft and assist them to effect separation to ensure there is no risk to safety. ” Class C airspace requires the separation of IFR and VFR aircraft. The terrain around Queenstown makes the application of many separation techniques problematic. Lightfoot says: “Queenstown is 1,200ft AMSL, within 6nm of the airport there are 10 peaks higher than 5,000ft AMSL. Due to the terrain, air traffic controllers are unable to see the entire control zone. When VFR aircraft are within 4nm of the airport they cannot hold and are required to join the circuit. We are very mindful of holding VFR aircraft since the terrain prevents pilots from maintaining vision of the horizon and they can become disoriented.

“To keep VFR aircraft clear of the IFR tracks would involve the use ofsegregated flightpaths. VFR operators are very concerned about having to hold in mountainous terrain. ” At present NZCAA has not made a decision to change the airspace classification. It will need to evaluate whether the changes present a safety risk to VFR aircraft.

New IFR arrival and departure procedures have also been introduced, as part of a PBN (performance-based navigation) redesign of Queenstown, to increase the number of aircraft that can be managed by air traffic control staff. This PBN initiative won the Jane’s 2013 international award for operational efficiency.

Lightfoot explains: “The previous arrival and departure tracks meant that aircraft were head-on with each other. This restricted the arrival rate to four-five aircraft per hour. New standard departure and arrival routes have been implemented. These new routes mean that arriving and departing aircraft are segregated around 80 per cent of the time. They have enabled the arrival rate to increase to seven IFR aircraft per hour. ” A 10pm curfew has been imposed on night operations due to noise management, and QAC has spent the past six years undertakingnoise planning to enable aircraft operations to take place up to 10pm. Scott Paterson explains: “QAC has developed its own noise standards and mitigation strategies. At present the court is reviewing the noise boundaries that QAC has proposed. The court has agreed with mitigation strategies but are still finalising the noise contours. These noise contours are not particularly relevant now but will be needed in 20 years’ time. ” Most arriving and departing jet aircraft fly over the town of Frankton. “Frankton is close to the end of the runway, it gets lots of sun and has lake views. It is a very desirable place to live or for holiday makers to stay,” says Paterson.

Plans are underway to provide noise mitigation for 380 Frankton homes.

The mitigation works will commence at the end of 2014 and will continue in annual or biennial tranches for the next 20 to 23 years. An estimated 170 home owners will be offered mitigation works in the first two years of the program. These initiatives include insulation, internal cladding, double-glazing and mechanical ventilation.

Interaction between QAC and the local community is managed through the Queenstown Airport Community Liaison Committee. The committee comprises an independent chair, three community members, representatives from the airport, airlines, general aviation users, Airways, and the Lakes District Council.

In addition to runway widening, QAC is planning expansion of apron and commercial areas. Parking and administrative space supporting private jets, helicopters and tourism fixed-wing will be relocated. This relocation will provide the foundation for these operators to achieve further growth.

Land acquisition is required to provide for the runway widening and expansion of groundside infrastructure. Negotiations with one landowner have been in progress for a number of years to acquire a parcel of land to the south of the runway. While negotiations are continuing it is quite likely that court action will be required to compulsorily acquire the land.

Queenstown has experienced significant growth since the introduction of jet operations and new instrument approach procedures. The commencement of night operations provides the platform for the next step change. A greater window of operations increases access to Queenstown to both New Zealand and trans-Tasman passengers.