THE BIG THREE aircraft manufacturers estimate that up to 2,500 of today's jet-powered airliners could potentially be equipped with Future Air Navigation System (FANS) datalinks, although they warn that the speed of implementation will hinge on proof of clear cost gains for airline customers.

Boeing has led the way with the FANS 1 package now being flown in the South Pacific with the 747-400. Dave Allen, who heads FANS projects across Boeing, says that around 300-400 of the type could eventually be equipped with the system, provided that new FANS routes open up across Asia.

The Boeing 777 fleet is also likely to be entirely datalink-equipped. The B-market models will have the system as standard when deliveries start at the end of 1996, and an upgrade will be available on the existing A-market versions.

To date, Allen says, Boeing has orders for 175 FANS-1 shipsets from 15 airlines.

He confirms that Boeing is looking at the potential to support the FANS-1 on older 747s, although he adds that the economics are not as compelling. "We're trying to understand what Boeing could add to such a task and whether it would be commensurate with costs," he says. Potentially around 50-150 aircraft could be fitted.

A development effort for the 757 and 767 is now getting under way, giving a potential for up to 150 aircraft, provided that the economic case for the FANS is proven on markets such as the North Atlantic. Allen adds that Boeing is looking at upgrading the flight-management system (FMS) on the 757 and 767, which would help towards systems commonality across the Boeing fleet. A decision is expected by December, with Honeywell and Smiths the main competitors.

The Boeing 737 fleet could also have as many as 400 installations, relying mainly on the demand from areas such as Russia and China, says Allen.

Airbus will have its initial AIM-FANS A system available in mid-1997, says Peter Potocki, cockpit-avionics manager. This initial offering, like Boeing's FANS-1, will be based on the current 622 offering, although Potocki guesses that a system based around the yet-to-emerge Aeronautical Telecommunications Network is likely to appear in 1999. Overall, he estimates that nearly 500 aircraft could be fitted with such datalinks.

Potocki stresses that, unlike Boeing, the Airbus solution will see the data-communications functions separated from the navigation systems in the FMS. This architecture should allow for future datalink upgrades without having to replace the core FMS.

McDonnell Douglas (MDC) avionics general manager Joe Ornelas sees potential for around 200-300 wide bodies to be fitted with FANS datalink equipment, with another 200-400 narrow bodies, although that would again be dependent on demand from China and Russia.

The MD-11 already equipped with the current ACARS datalink and satellite communications (satcom), could reach the FANS-1, but "probably not much beyond" without an FMS upgrade, says Ornelas. He also admits that MDC DC-10s are not capable of being upgraded "directly" to the FANS.

The MDC MD-88 and MD-90 narrow bodies have a FMS with "no FANS features", although work is under way to develop satcom and satellite-navigation systems, which would help prepare the aircraft.

Ornelas acknowledges that MDC will have to create a path towards the "full" FANS for the whole fleet. A potential solution centres on the creation of a new FANS capable advanced common flight deck, which would be retrofitted to DC-10s and forward fitted to existing production narrow bodies.

The plans also include common FMS software and Pegasus processor, developed by Honeywell, which would be fitted to the MDC MD-11, so giving commonality across the fleet.

Ornelas outlines an integrated FANS architecture hosted by the FMS, although he admits that there is pressure from airline customers, led by Delta Air Lines, for a "Federated" solution which would separate navigation and communications functions.

Source: Flight International