Airspace Management

If the aviation industry is unsure about the implementation of full CNS/ATM systems, it may be because of uncertainty about the costs and benefits to the provider states. At a recent CNS/ATM symposium in Vancouver, the only clue to benefits was in a video produced by the Air Transport Action Group and Inmarsat.

The video emphasised the waste that CNS/ATM could eliminate: Traffic delays in Europe and the United States cost their national economies 12 billion dollars a year, which is 10 times the cost of implementing FANS worldwide. It is claimed that every minute of ground delay of a 747 flight costs the global economy one million dollars. At any given time around the world 500 jets are sitting with engines idling, waiting for takeoff clearance. FANS will cut this waste by increasing the efficiency of airspace usage.

The full FANS-1 benefits can only be realised when all air carriers in a given region are equipped. Only the 747-400 and the Airbus A340 offer a package at the moment, although McDonnell Douglas is planning one for the MD-11, as is Boeing for the 777, 767 and 757. But FANS-1 kits are not yet available for many earlier types such as the 747 Classic, L-1011, DC-10 and others. Even if they were, they might still be considered too costly. Integrating these aircraft into a higher density FANS-1 ATC environment is yet another challenge.

By the end of last year, about 40 Boeing 747-400s had been fitted with FANS-1 avionics for use over the Pacific. Air New Zealand has all of its five 747-400s so equipped, Qantas has fitted more than half of its 18 aircraft, and United had FANS-1 on 24 of its fleet. The FANS schedule for 1996 calls for dynamic air route planning (DARP) to be introduced in stages from April onwards. Air traffic services supplied DARP will be introduced on Los Angeles/Sydney/Auckland with further stages consisting of: airline-proposed DARP for a single reroute with 50nm separation and conflict-probe; single reroute anywhere in the region; and then DARP for multiple reroutes anywhere in the region.

The process of reducing separations to 50nm (93km) laterally and longitudinally is well underway, and the Informal South Pacific ATS Coordinating Group (ISPACG) is now finalising the plan for the eventual reduction to 30/30nm (56/56km) separation. Crews participating in the 50nm (93km) separation trials will be required to downlink reports of RNAV distances to specified waypoints as near simultaneously as possible – initially to be ensured by using air-to-air communications. ATC will confirm separation at least every 30 minutes and remain in contact either directly or through controller-pilot datalink communications (CPDLC).

Qantas would only consider Boeing’s proposed 767 FANS retrofit package if there is proof of economic benefits in Southeast Asia, where the carrier predominantly operates the type. A company spokesman doubted that dedicated FANS routes would be an early reality in the South China Sea region, although it says the air traffic system there is almost at saturation point.

The airline is interested in FANS for the 767, but it has to go hand in hand with developments from the air traffic service providers on routes where they operate the type. With CNS/ATM facilities through the South China Sea area, it would help a lot with slot allocations, routing and altitudes. Qantas, when operating through Singapore, Hong Kong and Bangkok, is also often delayed on the ground waiting to be assigned a flight level.

One barrier to implementation may be lack of support from the operators of a large number of aircraft types which cannot, yet at least, be FANS equipped. Most of the ATC authorities are in the process of either installing or analysing a FANS capability, but the FANS minority may have to overcome the objections of the non-FANS majority. The benefits to them are going to have to be far more significant than the penalties against non-FANS-equipped aircraft.

As we go to press, New Zealand, Tahiti and the US have CNS/ATM facilities and procedures to accommodate FANS-equipped aircraft in the South Pacific. Fiji and Australia are not yet up to speed although trials have been conducted in Brisbane – the site of the oceanic control sector – to test the automatic dependent surveillance (ADS) and CPDLC components of CNS/ATM.

Meanwhile, FANS capability in domestic Australian airspace is currently a low priority because of efficiencies and improved separation standards gained in its recent airspace redesign, says AirServices Australia’s (ASA) Brian Kendal.

Kendal explains: “We’ve had some discussions on continental FANS routes, but they are very preliminary, and it’s not on our current work program because the finalisation of the Australian Advanced Air Traffic System (TAAATS) is taking up most of our energy. Also we’ve found that our new airspace redesign, which offers multiple routes to allow operators to take more advantage of prevailing pressure pattern winds, results in less opposite direction traffic, and we’re already achieving 30/30nm (56/56km) separation domestically on an RNAV basis. All that FANS-1 offers oceanically, is the CPDLC capability which we currently have in domestic airspace through VHF communications. So there is no real driving force within continental Australia to introduce FANS routes.”

He adds, however: “The capability remains, when there’s a need to connect up with the rest of Asia, to develop them and extend the routes up through Indonesia, Singapore and the other South East Asian countries, and we’d certainly always be prepared to move quickly in that direction.”