Over a million people a year fly into Queenstown – the New Zealand tourist and ski resort town set on the edge of a lake among a series of spectacular mountain ranges. Its location in the middle of the South Island of New Zealand relies heavily on air transport. Aircraft passenger numbers have increased 30% in the past three years, and a 40% increase in visitors in the next 10 years is predicted.
Airlines are increasing the frequency of flights and are looking at ways to access Queenstown at night as the current activity is confined to daylight hours. And before November 2012, aircraft were experiencing significant holding delays.
The clean sheet approach to PBN
Queenstown also has some of the most challenging terrain in the world – the high terrain, extreme weather and significant local tourism-related traffic flows call for unique air traffic management (ATM) solutions.
The ATM challengeAs air traffic continued to build into Queenstown, it became clear that a ‘clean sheet’ approach was needed to enable sustained development.
In response to the town’s strong growth and to ensure Queenstown’s skies remain safe and can cope with the larger numbers, Airways New Zealand
established a project in 2010 to redesign the entire Queenstown ATC system using a full suite of performance-based navigation (PBN) tools and procedures.
The challenge was to deliver a safer and more efficient ATM system in extreme terrain-rich airspace with only limited surveillance services available. By redesigning the airspace and implementing PBN-based Required Navigation Performance Authorisation Required (RNP AR) procedures, Airways aimed to reduce TCAS events within the control zone, simplify the task of controllers, provide consistent and predictable flight paths, and improve air traffic flow and efficiency.
Airways New Zealand’s implementation of performance-based navigation at Queenstown illustrates the benefits of the technology, says Phil Rakena, PBN Project Manager at Airways.
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Airways also sought to provide a number of benefits as a result of implementing PBN in Queenstown.
These comprised: enabling airline operators to make use of high-tech avionics equipment on their aircraft; improving efficiency and save costs for their business and their passengers; improving payload and associated efficiencies for airlines; reducing Airways’ pending navigational aid replacement programme costs; and improving traffic capacity at Queenstown Airport, particularly in adverse weather conditions.
The application of PBN procedures allows aircraft to fly very precise flight paths with a high level of accuracy – improving efficiency and safety and enabling jet operations to continue in a range of weather conditions.
The Airways solutionIn November 2012, Airways introduced new RNP AR approaches with fully-separated standard instrument departures and arrivals (SIDs and STARs). Stand-alone RNP AR approaches had been introduced in Queenstown more than a decade earlier, which significantly improved jet aerodrome access, reduced diversions and saved airlines millions of dollars per year in associated costs. These did not deliver good airspace capacity however.
Airways’ PBN implementation team created a completely new and fully integrated ATM package, making use of GE Naverus’ RNP AR design expertise for instrument flight procedures below 10,000ft, among the mountains. Airways’ aeronautical design and development team created all other elements of the IFR procedures.
It took more than two years from the concept being proposed in its first draft to the go-live date of 15 November 2012. Over this time intense consultation took place between the Airways project team, led by Airways PBN Implementation Manager Kevin Bethwaite, and key contributors and users.
Airways engaged a wide group of stakeholders during the project including key airlines, New Zealand’s regulator the Civil Aviation Authority, the Queenstown
Airport Company, general aviation users, operational ATCs and GE Naverus.
The new concept required Airways to lead and drive the project. Airways became an architect and conductor that initially sold the concept and then kept all parties focused on the outcome and facilitated the myriad of interconnecting needs.
Trials and trainingExtensive trials and staff and pilot training were required during the project. The use of Airways’ Total Control simulator allowed the concept to be trialled and developed to its final state, and played a
critical part in training the Queenstown ATC staff to the point where the cutover could happen with complete confidence.
Airline pilots who would use the RNP AR procedures, particularly those from Air New Zealand, Airways’ largest customer, simulated the concept and provided useful feedback. This trial feedback was critical to refining the procedures, and numerous versions were tested.
The turbo prop operators using Queenstown needed to upgrade their navigation capability, and significant co-ordination was necessary between these groups and the regulator.
Surveillance data of actual Queenstown traffic, with arrivals and approaches (STARs/APCHs) depicted in red and departures in blue. Very accurate flightpaths are flown, with only an occasional flight being given more direct by ATC under surveillance.
The Queenstown RNP AR approach concept, involving separated arrivals/approaches and departures (STARs/APCHs and SIDs) was put together by Airways PBN architect Kevin Bethwaite in consultation with a wide range of stakeholders. RNP AR designs were then prepared by GE Naverus.
Airways staff were also provided with training and knowledge of the aircraft navigation systems was incorporated into their training modules.
The implementation of PBN procedures into Queenstown has reaped enormous benefits to the aviation sector and the local economy. In the two years the procedures have been operational, Queenstown Airport’s capacity has increased to 12 aircraft per hour, compared with the previous five per hour in poor weather, in extremely mountainous terrain.
Airways can safely manage more than double the traffic with no requirement to tactically separate arrivals from departures while pilot and ATC workload has reduced in complexity, and the ATC pass rate at Queenstown Airport has improved from 40% to 80%.
All airlines operating in Queenstown are benefiting from dramatically reduced delays – from 2,000-2,600 minutes a month to around 330 minutes a month.
The reworked RNP AR departures have provided a large increase in take-off payload – up to 1,700kg off runway 05 for A320 aircraft.
Airline operators’ on-time performance has improved, and there have been significant reductions in holding delays, fuel burn, and CO2 emissions (see table).
In February 2013, Airways won the prestigious Jane’s ATC Award for Operational Efficiency, for the Queenstown PBN implementation
project. Airways was also the first ANSP in the world to receive the endorsement of ICAO as an instrument procedure design organisation for PBN and conventional designs.
Key customer supportAir New Zealand gave its full support and backing for the project from the outset. Captain Philip Kirk, PBN Programme Manager for Air New Zealand, had this to say about the project: “Air New Zealand has a significant interest in the Queenstown (ZQN) and associated Southern airports, Dunedin and Invercargill; however, it is ZQN that has shown significant growth over the last 10 years and is a key destination for the airline.
“ZQN could only be classed as a difficult environment to operate scheduled jet passenger transport operations,” he continues. “The high terrain, challenging weather and significant local tourism related traffic flows call for unique ATM
solutions. PBN is the key enabler here, in particular RNP AR. RNP AR procedures have been in use at ZQN since 2003. But previous RNP AR approach and departure procedures were considered ATM unfriendly as they had been designed in isolation from the total ATM system.
“As traffic built through ZQN, it became evident that a clean sheet approach was needed to enable continued growth, hence a project was commenced to redesign the entire ZQN ATC system using a full suite of PBN procedures. Air New Zealand worked closely with the Airways team throughout the project, providing many flight simulator trials at various stages to test and prove the design. The use of RNP 1 based STARs into RNP AR approaches to low RNP levels are a key component of the design. Likewise, a combination of RNP AR departures, with accompanying Engine Out SIDs combined with RNP 1 legs again provides for an optimum departure solution.
“The key safety benefits are clear,” concludes Kirk. “The controller can now issue a SID to a departing aircraft and know that this flight will be separated from all arriving traffic with no further input. From an operator’s perspective, the crew are no longer asked to comply with difficult to interpret procedural separation requests. Likewise on the arrivals, all arriving traffic is separated from departing traffic. This again makes for a safe and efficient ATM system, which reduces pilot workload.
“The safety benefits are clear, hence the airline’s support and backing for this key project.”
The entire Queenstown ATC system has been redesigned using a full suite of PBN tools and procedures.
