Air Transport World

On the brink of the SATCOM revolution. (satellite communications; include related article on low-earth-orbit systems)

As with saving the rain forests and ending world hunger, the difficulty in introducing aeronautical satellite communications into the airhne industry lies not in selling it as a concept but rather, in deciding how best to do it. But if the challenge appears datmting, the payoff is well worth it. IATA, not known for aggressive optimism, estimates that by the year 2000, airline industrywide savings from satcom use will be $5 billion annually; a single 747 will save nearly $350,000 in operating costs per year, compared with the cost today. United Airlines estimates that by 1997, it alone will be saving $300 million annually through satcorn use, not counting the revenues generated from the extra payload it will carry, owing to satcom ATC-related fuel savings. Northwest believes it will fly its Pacific routes 20-25% more efficiently with satcom-linked ATC. IATA Direct General -designate Pierre Jeanniot sayt that the airline industry will save $1.9 billion annually, if it can cut just 5 off its flying time.

However, before satcom can reach its full po- tential, a multitude of ambitious structure and sys- tem issues must be addressed, among them nothing

less than calls for a unified global ATC system.

The fruits of this technology are tantalizingly close. Here are the knowns about aeronautical satcom: Satellite-to-aircraft communications works well; there is a definite need for satcornbased ATC and on-board passenger services; the benefits of satcom by the end of the decade will far outweigh the cost of implementation; there are only variations in the degree of enthusiasm for all of the products that satcom brings.

Satcom offers the airline industry advances in three key areas: Air traffic control, passenger communications and company aircraft operational control communications. The greatest payoff will be in ATC.

The revolutionary and global qualities of satcom are what bundle major impediments along with its benefits, forcing a complete rethink of how the world's airspace will be managed with a system that first will supplement and eventually replace what has been achieved through 60-70 years of evolutionary development.

These changes are not surprising. For example, the idea that datalink will replace voice as the prime instrument of ATC communications has been debated for more than a decade. And the ascent of satcorn and satellite navigation into aviation orthodoxy was given its final blessing last year, when ICAO anointed the satellite-based Future Air Navigation System (FANS) plan (ATIE, 12/91).

But now that the direction has been laid down, the details need work-a lot of work. Most daunting is the challenge of orgmfizing a global ATC system to take full advantage of satcora's abihties.

When pressed, the most fervent backers of satcom technology and its benefits will admit that their urgent call for global cooperation, coordination and fast-track adoption and implementation of satcom and ATC standards and systems is a reach for Utopia. Europe, as small and culturally homogeneous as it is, still is mired in an ATC morass after more than three decades of failed coordination.

However, those Utopian goals need not be achieved before the majority of the world's aviation-system users can begin enjoying substantial benefits, experts say. And satcom and satcom-based

ATC has the advantage of being cheaper for all involved, cost being a major barrier to ATC harmony in Europe and elsewhere.

The key advantage of satcom is positive air-traffic control of aircraft in areas lacking radar coverage--largely but not limited to oceanic regions.

Using the automatic dependent surveillance (ADS) concept, ATC will be based on high-integrity on-board aircraft navigation systems linking position reports through satcorn. Initial savings will come through reduced aircraft separation standards, opening more capacity on the most efficient routes.

A few years later, there will be a shift in philosophy from fixed routes and air-traffic control to free routing and air-traffic management. Free routing will allow crews to change course based on information received while en route, reporting the changes through the ADS datalink. The only ATC function will be to compute the effects of route changes and resolve conflicts-- control as an exception--although this will require a significant amount of computer power from the ATM provider. …

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