The Land of the 'Lord of the Rings.' 

Enroute from Queenstown to Milford Sound, New Zealand in a Cessna Caravan.

 Showcasing the dramatic backdrop of the 'Lord of the Rings'.

"Queenstown. The Remarkable Challenge of RNP", continues.......

Tools of Trade.

QANTAS operate the Boeing 737-800NG on its Queenstown route and of these 737s, only those equipped with the more powerful 26K engines are scheduled for the service.  Additionally, the aircraft is equipped with technology that is the envy of some of its bigger brothers. Beyond the glass cockpit and the satellite navigation at the heart of its RNP capability, the aircraft boasts a variety of new age equipment.

Of premium interest is the HGS, or ‘Head-Up’ Guidance System, a device which has long employed by military aircraft. The HGS provides a means of transposing vital flight information into the pilot’s primary field of vision, negating the need to alternate between an instrument scan within the cockpit and an external assessment of the flight-path ahead. This is achieved through a unit mounted above the Captain’s head, which in turn generates the information and symbology onto a transparent screen, or ‘combiner’, between the pilot’s face and the windscreen. An HGS Annunciator Panel on the First Officer’s side provides information about the HGS status and warning annunciations.

Via a panel on the centre pedestal between the pilots, numerous ‘modes’ can be selected for the HGS, varying the information presented to best suit the phase of flight. A wealth of information beyond that normally available from a traditional instrument panel can be overlaid on the world outside. An aim point can be placed upon the runway and flown to, the landing flare can be guided in both timing and rate, speed error tapes permit precise speed management and TCAS resolutions can be accurately flown with the eyes outside the flight deck. There is a myriad of purposes for this state of the art equipment, but fundamentally they all equate to more precise flying in all phases of flight with the eyes remaining safely ‘outside’.

Another piece of advanced equipment is the VSD, or Vertical Situation Display. A component of the EFIS instrument panel, the VSD can be selected to show the vertical profile of the aircraft, its projected flight-path and importantly, the terrain ahead. By offering a pictorial display of the aircraft’s vertical situation with direct reference to terrain offers an additional aid to situational awareness above and beyond the traditional map display.

The system is designed to alert the crew of any discrepancies that may compromise the integrity of the approach. Certain messages such as the loss of LNAV or VNAV information, or the actual navigation performance (ANP) failing to maintain the standard required highlight as bold messages across the pilot’s map displays. Additionally, as display functions, warnings annunciate when the pilot’s altimeter settings are in disagreement and the Navigation Performance Scales (NPS) also sum any cross-comparison errors to ensure containment is maintained. Protection also exists against barometric setting (QNH) errors on final approach by way of the display representing a vertical offset from the planned path.

The QANTAS 737NGs also feature an enhanced ground proximity warning system (EGPWS), that features a look-ahead alerting system as distinct to the older systems that offered warnings based upon a rate of closure and level of separation purely with the landscape directly below. The aircraft also has a predictive windshear function that can alert the crew of an impending event well in advance of the indications becoming obvious through conventional instrumentation.

Key to maximising performance in Queenstown operations is the Electronic Flight Bag (EFB). While company manuals are also held here in a digital form on this tough-built laptop computer, it is in the area of take-off and landing performance that the EFB is a critical tool for Queenstown. It allows the optimum figures for arrival and departure in a way that traditional manuals would struggle to match. This equates to the best possible outcomes for payload both into and out of a relatively performance-limited airfield.

For all of this investment in technology, the point is not wasted on the humans that must operate the systems. The pilots that operate into Queenstown for QANTAS are limited in numbers and form what is termed as the ‘Control Group’. The purpose of the Control Group is to ensure that pilot recency into Queenstown is maintained. Given the frequency of service and the challenges of the port, the goal is for pilots to operate to at least 3 times every two months to maintain a level of competency on the sector. Additionally, the crews operating to Queenstown undergo additional training above any mandated requirements, including additional simulator sessions and a mandatory day of ground school each year. Through limiting the numbers, it is also easier to disseminate any new information relating to Queenstown without delay. Landings are also limited to Control Group Captains at the New Zealand port. They undergo additional training which is staged through a defined syllabus which calls for a defined number of arrivals and simulator sessions before their approval is down to the lowest available minimum altitudes.

There is no denying the challenges of Queenstown operations, but as always the key to safety lies in a combination of both technology and the human factor. Both elements are well supported by the airline through the 737NG fleet and under the experienced, watchful eyes of Captains Ian Brinkworth and Alex Passerini.

       Turning 'Finals' Runway 05 at Queenstown. (S.Ruttley)

Flying the Route.

The QANTAS flights to Queenstown starts well in advance of the aircraft pushing back the international terminal. Flight dispatch and load control start looking at the possible prevailing conditions a couple of days before the flight. Similarly, most crews will start reviewing the situation the day before, particularly with reference to the anticipated weather, while an extensive briefing is provided by QMET on the morning of departure. The Integrated Operations Centre (IOC) is also critical in tying all the components together preflight, but also continues to monitor the flight and liaise with it throughout and provide timely information in relation to weather and anticipated payload ex-Queenstown.

Flight planning this ETOPS flight is a critical process as a change in runway surface conditions can have a significant effect on performance. Crews also carefully confirm the anticipated satellite coverage for arrival and departure as this directly impacts upon the level of RNP operations that can be conducted. As mentioned, regardless of the weather, the arrival is always planned with enough fuel to divert to another port, nominally Christchurch. Once at the aircraft, pre-flight is a busy time of verifying the validity of the EFB database, ensuring the additional overwater equipment is on board, tuning the HF radios and attending to the routine duties of the day’s first flight.

Not long after departure, the flight deck becomes quite a busy environment. The flight log is completed to check the ETA at Queenstown and this is then forwarded to both the company and the control tower via ACARS. The latest weather forecasts for all possible ports are obtained and the suitability to continue the ETOPS operation is confirmed. Much of this information gathering must be achieved in a timely manner before VHF ACARS coverage fades approaching top of climb, although the option of obtaining such information by HF radio still exists.

Enroute to Queenstown, the crew will inevitably calculate a number of varied conditions for both runways for their arrival using the EFB. Some considerations include, the maximum acceptable tailwind components for landing on each runway, the performance penalties imposed should the runway surface become wet, and a modified approach reference speed should the aircraft have been loaded with a slightly more aft centre of gravity. They will also endeavour to work through some limiting scenarios for departure based on the current conditions if time permits.

The arrival to Queenstown is thoroughly briefed and this often includes the consideration of alternate approaches to a degree. This is because the fluctuating weather conditions at the airfield and the traffic sequencing can sometimes avail a change to routing and the assigned RNP procedure. Invariably a maximum flap setting, Flap 40, landing is planned and non-normal and diversion contingencies are discussed. This is all completed well before top of descent to allow the crew to focus on the approach ahead.

Given the potentially strong winds and high peaks that surround Queenstown, the aircraft is invariably slowed down earlier and the passengers and crew seated to safeguard against any possibility of mechanical turbulence. While containment along the route laterally and vertical limitations are closely monitored, ground speed also warrants due attention. Strong tailwinds can mean that the ground-speed of the aircraft may spike the EGPWS system. As always, a conservative approach to configuration management offers the safest solution.

The Queenstown RNP arrivals in clear conditions are stunning, with initial phases taking in spectacular views of the peaks, ski-fields and waterways. For Runway 05, the latter stages are conducted in the shadow of the towering ‘Remarkables’ before a descending right turn over Lake Wakatipu brings the runway threshold clearly into view. For Runway 23, the aircraft begins its turn back to the airfield near the hamlet of Cromwell and flies down the valley. Passing beneath is Bungy Bridge where A.J. Hackett started the past-time of bungy-jumping while ahead on short final, the 737NG makes a smooth transition around one final hill before aligning with the runway, at which time the autopilot is normally disengaged.

Once at Queenstown, the departure calculations are made and via the EFB a range of flap settings up to Flap 25 are available. The weather for the return flight is checked and the fuel/payload equation is refined to optimise the commercial aspects. As with arrival, satellite performance is confirmed to maximise the performance of the aircraft in the RNP sphere. The 737NG can also be operated ‘bleeds off’ on departure with the APU managing the pressurisation and the air-conditioning of the aircraft. This permits the bleed air that would be servicing such tasks to be used for engine power and maximise performance.

The departure is equally spectacular as the 737 climbs to a safe altitude overhead before setting course. The aircraft is maintained in the take-off configuration with a limiting speed of 180 knots until it is established at a safe point and heading away from the terrain. All the while, a safe ‘escape plan’ is available to the crew immediately in the event of a non-normal situation.

With the terrain well below and the aircraft re-configured for the climb and cruise, the course is set for home. However, regardless of how many times this arrival and departure is flown, it never ceases to amaze the crews themselves.                    

Where to from here?

Queenstown has often been seen as the RNP test case by many. Across the world, including in the US Congress, the development of RNP operations by QANTAS has been watched with great interest. Yet Queenstown stands in many ways as a test case for the broader use of RNP. The same elements that ensure safety in challenging terrain are also beneficial in avoiding noise-sensitive areas and facilitating efficient idle-thrust descents at less challenging ports. The future also sees RNP approaches transitioning onto existing ILS and GLS approaches, but at much closer proximity to the airport, obviating the need for long final approaches of 10-15 miles as they currently require.

As ICAO moves towards its 2016 goal of providing vertical path guidance to all runways, the QANTAS operations showcase the technology to its fullest potential. As other airlines adopt the technology at a growing rate, RNP will ultimately become the norm. For other types, such as the venerable Boeing 767, the future also lies with RNP. QANTAS recently decided to upgrade 17 of its  767 fleet for ADSB which means they'll be able to fly RNP-AR starting next year. The same flight guidance system found in the 767 currently operates RNP into Lhasa
Airport in Tibet.

RNP technology has brought the accessibility of airline services to Queenstown with an enhanced level of safety and service reliability. In its 90th year, QANTAS may pause to reflect on nearly a century of airline operations, but just as exciting are the years that lie ahead.  Destinations like Queenstown increasingly demonstrate that with the right technology and the right training, the future is already here.

For over 90 years of aviation, QANTAS has been at the forefront of numerous technological advances. From the dawn of the jet age and the Boeing 707 to the certification of the Future Air Navigation System (FANS) was in 1995. Today the airline is once again at the cutting edge with advanced navigation development. Nowhere is this more evident than in its challenging operations into New Zealand’s Queenstown Airport where the latest technology has their Boeing 737-800s setting the pace.

A Remarkable Place.

As destinations go, they don’t come much more dramatic or scenic than Queenstown, New Zealand. The mountain range known as The Remarkables tower 7,500 feet above sea level and along with the surrounding peaks draw ski enthusiasts from around the globe. But there is more to the region’s beauty than its seasonal white blanket of snow. On a clear day, its dramatic peaks reflect in the glassy surface of Lake Wakatipu and it is easy to see why it was found suitable as the mythical “Middle Earth” in filming “The Lord of the Rings”.

It is undoubtedly one of the most beautiful areas around which to fly and this is further evidenced by the amazing amount of general aviation traffic that operates from the airport and the surrounding waterways. There are aerobatic joy-flights, parachute operations, scenic journeys to the nearby Milford Sound, heli-skiing and so much more, giving the region a distinct sense of aviation. Yet the location of Queenstown Airport (NZQN) is not what one may regard as geographically ideal for aviation.

The airport effectively sits in a natural bowl, surrounded by peaks and ridge lines. The terrain is not the only challenging aspect as the winds that swirl around the basin can vary significantly in both speed and direction at different levels. Even on a crystal clear day, the combination of traffic and terrain can make manoeuvring an airline category aircraft challenging, so any deterioration of weather conditions further contributes to the demands of making an approach or departure.

The airfield has long been serviced by traditional non-precision approaches and specific visual procedures; however they are less than ideal. The absence of vertical path guidance is one factor, while the inability to align the approaches with the runway or achieve an effective instrument approach are others.

At the bottom end of the instrument approach, the runway is 30 metres wide and a touch under 1800 metres in length, effectively limiting the port to operations by Boeing 737s and Airbus A320s. While a very proficient control tower is operational, there is no radar coverage, further increasing the tolerances required for procedural separation. However, in the near future, a Wide Area Multilateration system will be introduced to aid situational awareness.

In so many ways, operations to and from Queenstown can present a variety of challenges to crews. As a destination the enhanced safety and efficiency on offer through RNP operations elevated the profile of the South Island ski resort in the aviation world. If RNP could be proven to work here, then its overall potential and credibility could only grow.

The Right Approach.

RNP approaches dispense with the limiting rigid straight lines, arcs and trapezoidal obstacle clearance of traditional instrument approaches and departures. By maintaining an ‘area of containment’ relative to the designed track, it is possible to permit optimised routing, clear of terrain, noise sensitive areas and high density airspace.

In the case of Queenstown, terrain is the limiting factor. While the challenges of terrain are obvious, operationally it makes the design of conventional VOR approaches and departure procedures a very challenging task and this equates to higher instrument approach minimas. Higher minimas in turn equate to a lowered assurance of being able to become visual when weather descends upon the airfield and this impacts directly upon the commercial reliability of the service.

For example, the best case scenario for a traditional VOR approach minima into Queenstown is 4,600’ or around 3,400’ AGL. In comparison, the RNP-AR 0.1 onto Runway 05 as pioneered by QANTAS can achieve a minimum altitude of 1451’, or a mere 291’ AGL. Furthermore, the RNP-AR approaches establish the aircraft on final, stable and aligned with the runway. By comparison, the VOR approach still calls for some challenging manoeuvring within the basin to ultimately achieve a landing as the approach leaves the aircraft well above profile to effect a straight-in landing.

Similarly, on departure, the RNP calls for a minimum cloud base 300’, while the old-style departure tracks require a 4000’ ceiling or greater. Like the arrival, the departure provides both lateral and vertical guidance to maintain the aircraft within its safe area of containment as it climbs to achieve the minimum safe altitude (MSALT) of 10,600’ within 15 miles.

Even so, there are RNP approaches and there are RNP-AR approaches. The former are generic approaches designed under the limitations of PANS-OPS Doc 9905, while the latter ‘Authorisation-Required’ tailored approaches are designed by GE/Naverus in conjunction with QANTAS. However, both containing the critical element of vertical path guidance and position the aircraft favourably to conduct a landing. However, the improvements are not merely at the minimum altitudes, as the vertical path guidance offered by RNP approaches is also a significant safety enhancement.

At Queenstown, safety is also enhanced through RNP by the precise ‘engine-out’ procedures on offer. In the event of either an engine failure on departure, or a single-engine missed approach, the RNP offers a safe resolution despite the challenges of the surrounding terrain. The complex tracking is automatically availed to the crew through the FMC when the engine fails. They need only execute the modified routing and continue to fly the aircraft along the new track, ensuring containment at all times. As with normal RNP operations, judicious use of the autopilot provides the best means of ensuring flight within the specified tolerances, while managing the aircraft’s flight-path and configuration.  So much so, that its use is not simply preferred, but required beyond certain points on the approach and departure.

In the face of challenging conditions, the growth of RNP operations into Queenstown has offered not only greater schedule reliability, but an enhanced level of safety. Even so, nothing is ever taken for granted and all QANTAS aircraft operating to Queenstown are required to carry an alternate, regardless of the weather. Even with the best technology, aviation is a dynamic environment......

Check back for the conclusion of  Queenstown. The Remarkable Challenge of RNP.

This article first appeared in Australian Aviation Magazine.