Aviation industry watchesas Australia tacklesADS-B questions
It is increasingly clear that Automatic Dependent Surveillance-Broadcast represents the future of air traffic management. But while many countries are embracing ADS-B, nobody is moving as quickly as Australia to turn its promise into reality.
Airservices Australia has already established itself as a leader in satellite-based surveillance by introducing the world’s most extensive ADS-B network. Now it is looking to expand the technology into new areas to create a truly national system.
For the past year Airservices has used ADS-B to provide continent-wide coverage of its en route airspace. Its next major step will be to bring ADS-B to lower altitudes. This time, however, the issues are far more complex, and the government and other airspace users are grappling with the same dilemmas confronting other countries as they consider satellite-based air traffic management (ATM).
Industry debate is under way in Australia as to when—and how—ADS-B should be introduced at lower levels. Airservices has proved with its en route network that there are no technological barriers; but with more stakeholders involved in lower airspace, questions about mandates and deadlines for equipage become more taxing.
The government has proposed a series of phased mandates, although discussions over this approach are still at an early stage. Significantly, regulators believe mandates can be met without the government funding to equip aircraft that many in the U.S. view as essential for the success of an ADS- program.
Airservices CEO Greg Russell says it is “not rocket science to figure out that this technology is going to play an integral part in the future of ATM . . . some of the periphery [details] are still being worked out, but [the system] is going to be satellite-based.”
By any measure, Australia has been a pioneer in ADS-B. When Airservices began operational use of the network in upper airspace across the continent, it was—and still is—the most ambitious ADS-B deployment. Australia was also the first to use this technology to implement reduced separation, and the first to introduce a mandate for ADS-B equipage in upper airspace.
Other nations, notably the U.S., started the ball rolling with ADS-B development and trials. “It is not important who was first [to develop] the technology, but who was the first to use it operationally so [the airline] industry can get the benefits—and certainly Australia led the way there,” saysTechnical Pilot Alex Passerini.
Many international and domestic airlines are already reaping safety and efficiency advantages from ADS-B. Qantas, naturally, has been one of the major beneficiaries, and Passerini says the carrier is a big supporter of ADS-B. This is evidenced by the fact that it is spending roughly AU$25 million ($25.5 million) to equip its fleet. It plans to finish retrofitting some types before the mandated deadline for upper airspace so it can realize the benefits earlier.
The Australian network is based on 29 ground units spread across the country, providing complete coverage of airspace above Flight Level 290 (FL290). An offshore station on Lord Howe Island allows coverage of important international routes into the East Coast, and Airservices has an agreement under which it exchanges some ADS-B data with Indonesia where their airspaces join.
Airservices began using ADS-B in 2004 and achieved full national coverage in December 2009. Under a directive from the Civil Aviation Safety Authority (CASA), all aircraft in upper airspace must be equipped by 2013.
What this gives Airservices is surveillance over vast areas of Australia’s hinterland for the first time. Its radar coverage is limited to a J-shaped area concentrated on the East Coast, with small patches of coverage around the major centers of Adelaide, Perth and Darwin.
Australia was in many ways the perfect environment for introducing ADS-B. Its large land mass meant that a cost-effective system was essential, and there was no existing surveillance infrastructure over most of the country that would have to be phased out. These conditions also exist for Nav Canada, another ADS-B pioneer. ADS-B “was made for countries like ours,” says Russell.
Network deployment cost AU$14 million, and the total rose to AU$80 million including necessary telecommunications upgrades. This was still a relatively modest price, considering that providing radar coverage over a similar area would be “prohibitive—you just wouldn’t do it,” Russell says.
The service is ADS-B “Out,” which allows Airservices’ controllers to see accurate aircraft positions on their displays based on GPS information transmitted by Mode S transponders. The refresh rate of ADS-B positions is twice per second, far faster than the 8-sec. updates for radar.
The safety benefits are obvious—controllers can see en route traffic over the entire country for the first time, and this helps them to prevent traffic conflicts. Previously controllers relied on procedural separation in non-radar airspace, which gave them only a predictive estimate of where aircraft were.
ADS-B has allowed controllers to cut aircraft separation distances to 5 nm, versus the previous standard of 30 nm, which gives them more flexibility to handle congestion.
This has been particularly useful for the many international routes that cross the West Coast of Australia and continue on to the major East Coast cities. Because these flights are mostly timed to arrive in the morning, there was “bunching” occurring as they entered Australian airspace at around the same time. Since more than 70% of the international aircraft using Australian airspace are ADS-B equipped, controllers can deconflict this traffic more effectively.
The introduction of en route surveillance has also been a big help during severe weather events, particularly in the monsoon and thunderstorm season in the north of the country. With aircraft positions now known more precisely, diversions and re-routing are a lot easier.
Another new procedure enabled by ADS-B is user-preferred routing (UPR), which Airservices hopes to introduce soon, Russell says. This will allow equipped aircraft to re-route during flight to take advantage of wind conditions and reduce fuel burn. An existing program known as flextracks allows airlines to choose between different defined routes, but UPR “is where the big [fuel] savings are,” says Russell. “These aircraft will finally be able to use their onboard avionics to full advantage.”
Airservices plans to trial UPR on routes between New Zealand and Australia, and then roll it out systemwide within the next 12 months.
Qantas’s Passerini says the advantages of ADS-B for en route flights are indisputable for the airline. From a safety perspective, the fact that controllers can see aircraft positions means they can monitor route adherence, and alert pilots if they stray off course. Conflict-detection capability will also help prevent problems before they arise.
On the efficiency side, controllers are able to approve altitude changes more readily, so pilots can fly at higher levels as they burn off their fuel loads. For example, a passenger jet will burn 1-1.5% more fuel if it is flying 2,000 ft. or more off its optimum altitude.
UPR will mean further benefits, says Passerini. More flexibility on transcontinental routes will make it easier for aircraft to take advantage of the jetstream eastbound, and avoid it westbound.
There has not been any serious pushback from airlines regarding the 2013 ADS-B mandate for upper airspace, Russell says. More than 70% of aircraft on international routes have the required ADS-B Out capability, but only 20-30% of domestic aircraft are equipped. Russell expects these numbers to rise quickly, and he notes that by 2013 carriers will have had five years’ notice of the change. Virgin Blue, for example, is expected to have a large turnover in its domestic fleet by 2013, which will help boost the domestic ADS-B percentage.
Qantas has no problem with Australia’s mandate for aircraft equipage, and supports CASA “drawing a line in the sand” for ADS-B, says Passerini. The airline is making a considerable investment to ensure that its entire mainline fleet will be ready before the deadline.
So far, all of the airline’sand and -400s meet the ADS-B standard. All new deliveries of are equipped, but the carrier is still working to retrofit 15 of this type that were delivered before ADS-B was offered.
Qantas expects the -800 fleet to be ready 9-12 months before the deadline. The carrier decided it was “worth doing ahead of time,” says Passerini. Airservices operates a “best-equipped, best-served” policy that helps encourage the early adoption of ADS-B, Russell notes.
Of the airline’s 26, it has so far decided to modify 17 of the youngest for ADS-B. Some of the 767s will likely be phased out, but the carrier could still decide to retrofit more, Passerini says. The 737-400s are due to be retired, so they won’t be upgraded. In the Jetstar fleet, all of its A330s have been equipped, as have three-quarters of the .
While it is hard to find anyone to fault the introduction of ADS-B at higher altitudes, there’s more disagreement over its application below FL290. Lower airspace brings general aviation and regional carriers into the mix, with a new range of issues to address.
General aviation operators are concerned about having to buy expensive equipment that they cannot offset through efficiency gains as airlines can.
To address this, in 2008 the Australian government proposed a scheme where avionics upgrades needed for ADS-B would be subsidized. This would have allowed the government to accelerate its move to full ADS-B coverage, with equipage mandated by 2012 for all aircraft that are required to carry a transponder. However, the plan fell apart when it became clear that legal and tax complications would make the idea untenable. The failure of this plan “was a lost opportunity,” says Paul Tyrrell, CEO of the Regional Aviation Association of Australia (RAAA).
Regulators are now making another attempt at requiring ADS-B in lower airspace. A government aviation white paper stresses this goal, and CASA issued a discussion paper late last year that proposes a timeline for expanding the ADS-B requirement.
As Russell describes it, the basis of the plan is a series of mandates applying to specific classes of airspace. A notable difference from the last attempt is that there is no subsidization on the table this time. “We’re not going into incentives; we think that a series of gradual mandates with plenty of notice is the way to proceed,” says Russell.
The plan is still fluid, and much debate is needed before it becomes a formal proposed rule, Russell says. “People generally agree with the principle, but the question of timing is always something for discussion.”
Technically, expanding the system will not present many challenges for Airservices since its “backbone” has already been established. Coverage spreads upward in a cone from the ground-based stations, so there are already areas around the ADS-B stations that are covered.
Airservices will have to install more ground units to fill the gaps, but the cost should not be greater than the amount spent on the upper airspace network.
The first mandate proposed by the CASA discussion paper would apply to airspace over FL110 within 500 nm of Perth, with all aircraft required to have ADS-B Out capability by the end of 2015. Air traffic in this area is increasing thanks to the growth of the mining industry in Western Australia.
By the end of 2017, the requirement will expand to all Class C, D and E airspace—essentially, controlled airspace around major and medium-size airports, and the busy mid-level airspace along the East Coast. This timeframe will also apply to Class G airspace above FL110, which is the uncontrolled airspace over most of the country.
From 2020, ADS-B will be required at all altitudes around regional airfields with scheduled service.
The Aircraft Owners and Pilots Association (AOPA) of Australia says it recognizes the advantages of ADS-B for the broader aviation industry in improving air traffic services. However, the organization is concerned about the timing of the proposed mandates for lower airspace, and does not believe they should apply to all aircraft.
General aviation faces “a disproportionately bigger investment in relation to aircraft size, and gains the fewest benefits” from ADS-B, says AOPA Vice President Andrew Andersen. A subsidy of any kind would be welcomed by the GA sector, and Andersen says it was a “disappointment” that the previous subsidy plan failed.
A subsidy plan is about the only reasonable way GA users could equip quickly enough to meet the timetable as outlined in the CASA discussion paper, says Andersen.
However, he says general aviation “has got to be realistic—there is no subsidy on the table, so we have to work with what we’ve got.” In the absence of a subsidy, there must be an adequate transition period, says Andersen.
The current transition timetable being proposed is not adequate, according to AOPA. Andersen says the 2017 deadline should be pushed back, since the GA fleet that would be affected could not be completely equipped in that time. Aside from anything else, suitable products are not yet available at a reasonable cost, he says.
Additionally, Andersen does not believe there is any need for aircraft that operate under visual flight rules (VFR)—particularly in Class G and E airspace—to be forced to equip for ADS-B. General aviation aircraft operating in Class E are already required to carry transponders, he notes.
The focus of mandates should be on instrument flight rules operations and aircraft in controlled airspace, says Andersen. “Even the harshest regulatory view wouldn’t make the safety case to cover all aircraft.”
Another group that will be affected by the ADS-B expansion comprises the regional carriers that serve smaller communities. “Everyone is aware that over time ADS-B is the future, and we’re generally pretty supportive,” the RAAA’s Tyrrell says. “We’re all for new technology if it helps operators increase safety and stay in business, and increases efficiency.”
However, Tyrrell believes some sort of incentive should be considered. “The black boxes that go in the aircraft are quite expensive—the upfront cost can be enormous,” he notes. If subsidies are off the table, tax incentives could be used to allow operators to write down installation costs very quickly.
Deciding how to address concerns like these appears to be the major remaining obstacle to the expansion of ADS-B in Australia. And if they are smart, other countries will be watching closely to see how these questions are resolved.