Pathfinding

New Zealand’s New Southern Sky programme is already delivering benefits as it moves to crucial third stage.

As the New Southern Sky (NSS) programme moves to its third and final stage, the benefits of the wide-ranging initiative to modernise New Zealand’s aviation system are becoming increasingly apparent.

The programme, a partnership between the country’s civil aviation authority, ministry of transport, and Airways Corporation, seeks to implement New Zealand’s National Airspace and Air Navigation Plan (NAANP). The plan, which is New Zealand’s response to ICAO’s Global Air Navigation Plan, provides clear direction on incorporating new and emerging technologies safely into the aviation system by 2023.

A recent key milestone for the NSS programme was the mandate for Automatic Dependant Surveillance Broadcast (ADS-B OUT) for aircraft operating above flight level 245 in the New Zealand Flight Information Region (FIR).

Using a combination of satellites, transponders and Global Navigation Satellite System (GNSS) receivers, ADS-B involves aircraft self-reporting their GNSS derived position. It is compatible with other surveillance systems and will enable the Airways Corporation, New Zealand’s air navigation service provider (ANSP) to increase air traffic system capacity by improving positional accuracy on air traffic control displays, as well as increasing coverage volume by 40 per cent.

That ADS-B requirement, effective from 31 December 2018, is paving the way for NSS stage three’s proposed ADS-B OUT mandate in all of New Zealand’s controlled airspace by the end of 2021.

NSS programme director Steve Smyth encourages operators and aircraft owners who fly below FL 245 to install ADS-B transponders as soon as possible, rather than waiting for 2021.

“This is important because when we ramp up the rate of installations, avionics workshop capacity will become increasingly under pressure and we don’t want late adopters to be disappointed,” says Smyth.

New Zealand’s civil aviation rules were also updated in 2018 to outline the requirements for ADS-B OUT – New Zealand has chosen to use the 1090 MHz extended squitter (ES) ADS-B system, rather than the Universal Access Transceiver system, which is used in the United States.

Another key NSS initiative is the implementation of Performance Based Navigation (PBN), which is being rolled out through a collaborative approach by participants in New Zealand’s aviation sector, working together on PBN procedures, technologies, and a rules framework.

This shift from ground-based to satellite-based navigation (utilising the Global Positioning System) as the primary means of navigation, has allowed Airways and its subsidiary Aeropath to design an increasingly efficient and flexible routing structure.

As more and more Instrument Flight Rules (IFR) flights in New Zealand are flown on PBN-enabled aircraft and routes, the benefits of PBN make a compelling case for the continued adoption of this technology at a system level.

A 2017 NSS Cost/Benefit Analysis report released at the early stages of New Zealand’s PBN rollout found that 2.2 million more passengers a year were benefitting at non-ILS served runways from the increased safety provided by vertically guided PBN procedures.

That report also identified significant economic and environmental benefits enabled by PBN, with an approximate 4.9 million tonne reduction in CO2 emissions. Direct economic benefits were found to be worth $128 million, due to increased flight efficiency as well as airport accessibility and delay reduction.

At Queenstown Airport, a key arrival point for visitors to the South Island’s tourism hotspots, the introduction of PBN procedures has led to a 17 percent reduction in passengers’ diversions as a result of poor weather conditions.

More recent PBN trials at Auckland, Christchurch and Wellington’s international airports have continued to deliver positive benefits in the form of reduced flight times and distances (with resulting fuel savings and CO2 emission reductions) along with savings from reduced passenger delays.

PBN’s life-saving potential

When thinking about the benefits arising from the adoption of PBN, it’s usually associated with commercial airlines and their passengers – the time, fuel and money saved as a result of more direct and precise routes.

But there are also smaller scale, yet life-changing benefits coming out for IFR rotary fleets.

Providing rapid emergency medical services to New Zealand’s remote communities wouldn’t be possible without reliable rescue helicopter operations, linking far-flung and hard-to-access parts of the country to secondary and tertiary hospitals.

Whether a patient is on the West Coast of the South Island, needing to be transported to Christchurch Hospital, or on Auckland’s Great Barrier Island and facing a long journey by road and ferry, New Zealand’s geography with its high terrain and low population density mean that rescue helicopters are a significant rapid response tool for the country’s medical system.

And PBN is starting to help New Zealand’s rescue helicopters to get to some of their destinations faster and more reliably.

Rob Arrowsmith (pictured), a pilot with the Auckland Rescue Helicopter Trust (ARHT) and a member of the NSS Working Group, says that until the introduction of PBN, rescue helicopter pilots were mostly reliant on visual flying.

Given that ground-based navigation aids in New Zealand were normally located near major airports, they were of limited use for rescue helicopter services.

With the advent of PBN and GPS based navigation, rescue helicopters now have options for getting down low and out of the clouds away from major airfields, says Arrowsmith.

“A really good example is from Auckland up to Wellsford, the centre of the Rodney District. We go up there for a lot of farming incidents, car accidents, and medical events.”

The 36-mile leg up to Wellsford takes about 18 minutes for a rescue helicopter to fly, compared to a road ambulance taking up to 90 minutes in heavy traffic.

But the first PBN route developed for Wellsford saw crews having to approach the town from the north, adding an extra seven minutes’ flight time.

Recently the ARHT secured extra charitable funding to develop more PBN routes, including one for Wellsford which removes the need to approach from the north, shaving off those crucial minutes.

“In the world I live in you’ve got a paramedic sitting in a road ambulance with a very sick patient and they’ve got to know if they’re waiting for a helicopter to turn up or if they just start driving,” says Arrowsmith.

“The aim is to make IFR take the same amount of time as Visual Flight Rules (VFR). The challenge is that you’ve got to have a route structure where you’re flying on the same line as if you were VFR.

“We’ve now got the funding to have a network of routes and instrument approaches using GPS which allow you to fly in the same amount of time as on a nice day.”

Arrowsmith says some people were sceptical at first, but crews have now been able to fly to Wellsford using PBN in the same time as they could ‘on a blue sky VFR day’.

“In the past we’d keep trying with bad weather VFR, which is bad for everybody. It’s bad for safety and it’s bad for the patient.

“It’s not just about survival, whether someone lives or dies, it’s also about their long-term benefit of life.”

Future route development

Now that the Trust has developed a network of PBN routes to Auckland’s Great Barrier Island, and towns on the Coromandel Peninsula, it is looking to develop routes to more towns near Auckland if it gets the necessary funding.

There are still challenges with PBN routes for rescue helicopters in Auckland, though.

Auckland has large areas of controlled airspace to the north and south of the city, surrounding Whenuapai Air Force base and Auckland International Airport respectively.

Arrowsmith says with current PBN procedures there were wide tracks, which pushed you higher up into controlled airspace.

“With getting tighter Required Navigation Performance (RNP) with better technology, and with the Civil Aviation Authority coming onboard, that will allow us to fly closer to controlled airspace without being in it, and will allow us to be lower over terrain,” he says.

The ultimate goal would be RNP 0.3 (H), which in the South Island with its mountainous terrain and lower freezing levels, could open up more days for rescue helicopters to fly – currently their freezing levels are often lower than the minimum altitude they can fly under IFR.

“Emergency response aircraft don’t have anti-icing equipment like airliners do,” says Arrowsmith.

“By lowering the minimum safe altitude along the route with tighter tolerance we should be able to fly below the freezing level.”

By using an augmented GPS system, rather than just the standard GNSS, the accuracy of the system’s position is significantly improved. With RNP 0.3, the aircraft’s navigation system must be able to calculate its position within a path 540 metres either side of the track centreline.

Bringing in a Satellite-based Augmentation System would allow for RNP 0.3 en route, as well as LPV approaches, with its lower minimums.

“It would be pretty amazing to one day get an ILS style approach into Pauanui or Whangamata, little towns on the Coromandel,” says Arrowsmith.

“If we get it right, whether it’s good weather or bad weather, we still get to the patients and get them out of there.”