One of the paradoxes implicit in contemporary aviation is the mixture of cutting-edge and antediluvian technology that combines to make routine high-speed transoceanic flight possible.

While we careen along in our state-of-the-art jets at 80 percent the speed of sound in non-radar airspace, oceanic air traffic controllers, relying on position reports conveyed over scratchy HF radios, continue to track us on little slips of paper -- just as they did 60 years ago. As United Airlines' Tom Holford, senior staff representative, flight operations technology, puts it, "The systems that we are currently using that preceded FANS are the best technology that World War II had to offer, because that's the last time we made a change of this magnitude."

FANS is the Future Air Navigation System, the much-touted solution that was supposed to replace procedural ATC with data-linked text messaging, precise satellite-based navigation and automatic position reporting when it was first proposed more than two decades ago. FANS was ultimately intended to relieve aviation's dependence on line-of-sight ground-based nav aids, moving the surface infrastructure off-planet and laying the foundations for true area navigation. Thus, aircraft would be freed from the rigidities of adhering to published routes or even flexible track systems.

Over the years, FANS evolved into the GPS- and satcom-based synthesis we now know as CNS/ATM, or "communications, navigation and surveillance [for] air traffic management." Thanks to the phenomenal accuracy of the GPS-- only a hypothetical concept 20 years ago when FANS discussions began at the ICAO level -- and the ability to quickly relay data via communications satellite, a nifty byproduct of CNS/ATM is automatic dependent surveillance (ADS), allowing controllers to for the first time "see" near-real-time locations of aircraft flying in non-radar environments.

Virtual Radar

Now available as an option in at least 50 percent of the world's oceanic and remote-area airspace, CNS/ATM not only provides a higher level of safety, it is reputed to enhance fuel-efficiency and reduce overall flight times. This is due, in part, to the "virtual picture" controllers use to track FANS-equipped aircraft, allowing them to award more direct routings. (Or as NBAA International Operations Director Bill Stine puts it, the ADS-fed computer-generated display provides controllers with a "pseudo-radar environment" in remote areas where real radar coverage isn't possible, giving them positive control of traffic.)

Furthermore, CNS/ATM not only allows easier and faster weather diversions, it even permits operator-specific dynamic rerouting to counter wind changes once a flight is in progress (more on that later), facilitating for the first time true area navigation in the oceanic flight environment. Think of it as the initial step toward another futuristic navigation concept hotly promoted by the FAA: Free Flight. As we'll see, ideally, under the new system, operational control will move more from ATC to the operator.

But only operators of aircraft equipped with FANS avionics packages -- which include controller/pilot data link communications (CPDLC) and flight-management systems modified with expensive software revisions to support ADS -- can take advantage of these improvements. And right now, that's the airlines, which lobbied hard in the early 1990s for FAA and other oceanic ATC providers, as well as airframe and avionics OEMs. Business aviation has yet to embrace the technology.

Until ATC providers make CNS/ATM mandatory in most parts of the globe, as they're doing now with reduced vertical separation minimums (RVSM), they'll be forced to operate two disparate traffic-management systems side by side into the indefinite future: CNS/ATM and the traditional procedural-based network of published routes and flex tracks, the mix of modern and archaic technology we cited at the beginning of this report. "To a certain extent it will be complex integrating both old and new systems," the FAA's Tom Barclay, air traffic manager at Oakland Center, which provides oceanic ATC for a huge portion of the Western Pacific, told B/CA during a recent visit to the facility.

"We will still be capable of providing services in a mixed environment . . . so no one will be excluded," Barclay continued. "We believe that our new system will allow greater flexibility, but there will be some penalties for unequipped aircraft. That notwithstanding, we also believe the penalties will be less than those imposed by our current [procedural] system, due primarily to the prediction capabilities built into the new equipment. [It] will predict conflicts and also take into consideration the type equipment the aircraft has and, therefore, the separation that will be necessary. That is, the computer will recognize the RNP [required navigation performance] standard via the suffixes on the filed flight plan -- so make sure you get them right when you file!"