Kevin O'Toole and Julian Moxon/AMSTERDAM
ALMOST BY definition, the debate over the Future Air Navigation System (FANS) has been strong on the benefits of tomorrow's technology, but a little weaker on how the world will get there.
There are encouraging signs that the debate is coming back to Earth, however, as the technology starts to make the transition from theory into practical airline implementation.
The change of emphasis was clear from the Flight International Airline Navigation Conference '95, held in Amsterdam on 25-27 September, as suppliers and airlines alike got down to discussing hard economic realities.
The overall message is that the FANS will have to be implemented a step at time and that those steps will only be taken once airline management can be persuaded that the technology will yield real cost benefits.
It is such economic arguments, which have driven the experiment, taking place in the South Pacific, with Boeing 747-400s now being flown equipped with FANS-1.
United Airlines reports that on its longest Pacific routes, the annual saving is likely as much as $750,000 per aircraft, with an average figure of $250,000.
The cost benefit is further emphasised by the fact that Boeing's FANS 1 package is based around the 747-400's existing cockpit systems, including the ACARS datalink sending messages using the ARINC 622 standard.
"FANS 1 on the 747-400 made clear economic sense. It didn't take a rocket scientist to work out that the airlines could make a large amount of money," says Dave Allen, who heads FANS projects at Boeing.
The cost benefits are already opening up elsewhere in Asia, with China and Russia the latest to announce intentions to base future ground systems around the FANS. Aviation authorities in Africa and the Indian Ocean are also moving in the same direction.
George Birutis, ARINC programme development director, points to a massive potential gain from flying great circle routes over the Russian Far East. On 2 September, a United Airlines Boeing 747 forged the way with a FANS-1 proving flight from Chicago to Tokyo, over Russia, which Birtus describes as "history in the making". He estimates potential for savings of up to $12,000 per flight, or $2 million a year on such routes.
JUSTIFYING ATN
While the FANS is on course to become widespread in Asia within the next three years, the immediate prospects on North Atlantic services remain less certain.
The goal on both sides of the Atlantic is to launch into the FANS based on the Aeronautical Telecommunications Network (ATN) datalink, which is more suitable for the high-density traffic in Europe and the USA than the less-capable and slower 622 standard.
Technically, the ATN system should be operating some time after 1998, but the exact time-scale remains hazy. The economics for the airlines are also less certain.
British Airways is a case in point. BA FANS specialist Paul Roper says that while the airline intends to press ahead with the FANS 1 on its 747-400s as Asian routes open up, it is still unconvinced by the economics for using ATN across the Atlantic or in North America.
"We will equip [with ATN], but only when it is clear there is a realistic associated cost saving," he says. At present, he admits that the benefits are not apparent, given the routes and separations already achievable, using existing systems.
Some of the greatest benefits in cost and capacity across the Atlantic are anyway due to come, not from satellite navigation, but from the implementation of 1,000ft (300m) reduced vertical separation minima, is scheduled to be introduced in late 2001.
Roper adds that it is up to the air-traffic-control (ATC) providers to demonstrate how ATN-based FANS will produce fresh benefits. "We require them to show us how they would utilise the system," he says.
For its part, BA is resigned to having both standards, and Roper calls for development of a dual-stack system. "Our preference is for ATN, but we have to be realists. Both systems will be sitting alongside each other for many years to come," he says.
Boeing, too, remains agnostic over the present cost case for a North Atlantic ATN. "My financial handlers are not going to let me drag out the cheque book until a clear business case is made with the airlines," says Allen. He says that Boeing, like its customers, is prepared to be convinced by the technology, but believes that the economic justification is missing.
Allen even offers to make Boeing's sophisticated economic-modeling techniques available to the ATC providers to help them try to balance the equation.
Airbus avionics manager Peter Potocki, also cautions that it is in the hands of ATN supporters to fight for implementation, or else risk losing ground, to the more pragmatic 622-based systems. Airbus, he says, will support either.
The message on data-linking standards, like much else within the FANS debate, is that the move from existing navigation systems towards the ultimate goal of free flight is likely to be through a gradual evolution.
"We cannot wait for the benefits that ATN or automated air-traffic management may eventually bring, we must look for the gains that we can find today," says Denny Helgeson, FANS director at Rockwell-Collins Avionics.
Echoing a general view among the avionics community, he puts forward a phased introduction, starting with the existing infrastructure, and only gradually working to a "more-robust" automation of systems, both airborne and ground-based. The prospect is that the type and speed of implementation will vary by region, as the South Pacific example already shows.
WARY AIRLINES
The idea of a phased implementation is comforting as far as it goes, but airlines continue to be wary of the prospect of taking on a series of expensive, piecemeal systems solutions, which will require constant upgrades. The universal call is for commonality and future proofing.
Perhaps the most encouraging news to come out of the conference is that the airframe and avionics manufacturers appear to be listening to the operators.
Allen promises that Boeing will look for greater commonality across its fleet, with customer discussions taking place with 757 and 767 operators on a FANS solution, probably based on a new flight-management system (FMS).
McDonnell Douglas (MDC) is also looking at a new common flightdeck and FMS upgrade, which would allow a path towards FANS for the MD-11 and MD-80/90 as well as retrofits for the DC-10. The flightdeck would have the added advantage of commonality with the Boeing 777 and 737.
The MDC proposal is for an integrated architecture with navigation and communications both hosted in the FMS, but the company admits that customers are pushing for a "federated" solution, which would potentially allow upgrades to parts of the system without replacing the entire box.
The Airbus AIM-FANS system, due for certification in 1996 and service by mid-1997, does separate out navigation and data-communication functions, with the aim of providing an easier upgrade path.
Ben McLeod, programme director of strategic alliances at AlliedSignal Aerospace, estimates that "as a rule of thumb", operators looking to take advantage of a FANS should expect to retrofit any aircraft that they intend to keep for more than five years.
He warns, however, that even with the retrofit options now being promised, there will be aircraft for which a FANS will be either "impractical or too costly". For those the brave new world of free flight is likely to have its penalties. "I believe that in the end there will have to be operational limitations imposed on aircraft not equipped for even minimal FANS," he warns, suggesting that they will simply not have equal access to optimum flight trajectories.
Tom Graff, FMS procedures manager at United Airlines, gives an equally stark message for operators. "Those who choose not to participate should be warned that their choice not to improve could result in their financial demise," he says.
The enthusiasm for the free-flight concept now coming out of the USA is not hard to understand, given the ambitious pace, which the US Federal Aviation Authority is now setting on satellite navigation.
In 1994, the global-positioning system (GPS) was approved as the primary means of navigation in oceanic airspace, and by early 1998 the plan is to extend that to domestic airspace as the wide-area augmentation system (WAAS) comes on line.
The WAAS essentially consists of a network of ground-based reference stations designed to monitor the GPS satellites and detect any errors in their signals. This data is fed through to a master station, which then passes on the information to an aircraft's GPS receiver via a communications satellite.
The first contract for the WAAS, handed over in August, calls for 35 reference stations, with a master station on either coast, covering the whole of the USA.
By 2001, when the project will be complete, the aim is not only to use the WAAS for en route navigation, but also as a primary means for a Category I precision approach.
In the longer term, the FAA is looking at providing Cat II/III accuracy through a local-area augmentation system concept, similar to the WAAS, but with a single ground reference station covering traffic in a 45-55km (25-30nm) radius around an airport.
Although the WAAS is essentially a domestic US venture, FAA technical advisor Kanwaljit Sandhoo explains that other nations will be invited to use the network. That could realistically involve no more than a relatively cheap investment in reference stations. The USA's near neighbours in South America, are already clear candidates to take up the offer.
CAUTIOUS EUROPE
Even outside the Americas, the concept is understood to have attracted some interest, although more distant countries would probably require a hefty investment in a master station to achieve the necessary levels of integrity.
While the USA forges ahead, Europe is perhaps understandably taking a more cautious view of the free flight goal.
The region, after all, not only has the world's densest air-traffic environment, but also the most-developed ground-based infrastructure. The view in Europe is that this will be capable of performing many of the ATM functions required for at least the initial stages of the FANS.
At the conference, Eurocontrol's Roland Rawlings outlined a prospective timetable under which the EATMS (European air-traffic management system) "...will achieve initial operational capability around 2005". He foresees a ten-year transition period to the full EATMS, with full operational capability in 2015.
Europe has its own plans for augmented satellite navigation, but again the time-scale is less aggressive than for the WAAS. The GNSS 1, the initial, augmented satellite-based system, will be part of the system architecture by 2005 says Rawlings. He stresses, however, that it "...will not provide the integrity and availability for stand-alone input to area navigation", leaving a need for ground aids through to 2015.
The plan is to provide augmentation via The European Geostationary Navigation Overlay Service (EGNOS), and will employ two leased transponders aboard Inmarsat communications satellites, which will cover Europe and other areas, which come under the footprint, such as Africa. The associated ground infrastructure is already funded, and Eurocontrol says that talks are going on with other nations.
Source: Flight International
