airlines_crowding_000804 On the runway at New York's LaGuardia International Airport recently, passengers aboard a shuttle flight to Washington, D.C. had no idea of the danger that was ahead of them.
While revving up for takeoff, their plane suddenly slammed on its brakes, lurching them forward. The aircraft had come within seconds of colliding with another commercial jet coming in for a landing at LaGuardia.
The reason: Air-traffic controllers, by mistake, had put the planes on a collision course.
Airplane gridlock
Near misses like that are on the rise as controllers struggle to clear the gridlock that plagues the skies and runways at the nations airports. But as the air-traffic-control system reaches the limits of its capabilities, there is a space-based solution on the way that will make flying safer and more efficient.
The
Federal Aviation Administration (FAA), which now tracks planes through ground radar, has been developing a space-based air-traffic-control system that uses Global Positioning System (GPS) satellite technology. 
"Air traffic control is definitely handicapped by its initial technology."
The plan involves a number of
satellite-based technologies that will allow commercial airliners to fly more efficiently and better handle inclement weather."Air-traffic control is definitely handicapped by its initial technology," said Wolfgang Demisch, a former aerospace analyst now at the investment banking firm Wasserstein Parella in New York.
More efficient
A satellite-based control system is more efficient and more economical because it does away with the expense of traditional ground-based radar systems, Demisch said.
The solution comes as more and more aircraft take to the skies in what is becoming an increasingly crowded environment. According to FAA statistics, there were 9.2 million departures from U.S. domestic airports in 1999 -- a figure that is expected to swell to 9.9 million by 2010.
Coupled with bad weather conditions, too many flights can spell disaster for the nations commercial carriers.
"We desperately need this system today," said Dave Swierenga, chief economist for the
Air Transport Association, a group that represents the major U.S. airlines. Poor weather accounted for 70 percent of all delays in 1999, costing the airlines about $2.2 billion.Part of the FAAs plan would be to install a system called ADS-B (Automatic Dependent Surveillance-Broadcast) which the agency plans to use to unclog serial gridlock by allowing planes to fly closer together in low-visibility conditions.
FAA regulations usually require air-traffic controllers to keep aircraft at least 5 miles (8 kilometers) apart horizontally during low-visibility conditions.
How it works
The system works like this: Pilots know their own positions from their
GPS receivers, which use precise timing signals emitted by a network of satellites. The planes can broadcast that information from cockpit to cockpit where pilots can read the information on a computer screen. Nearby aircraft know exactly where they are and can send the information to ground systems.
"By allowing precision approaches on parallel runways more planes will be able to land on time," Swierenga said.
UPS Aviation Technologies, a unit of United Parcel Service, will be the first commercial transportation company to employ ADB-S in its fleet. It hopes to have the system up and running by the end of 2002.
Paradigm shift
"ADB-S technology represents a paradigm shift from the old World War 2 radar surveillance system," said Ken Shapero, spokesman for the UPS Air Group. "We believe that the current troubles in our [air-traffic-control] system is the result of reaching the limit of what radar can do."
The ADS-B system is more accurate than radar because it updates itself every second, while radar information is relayed just once every 12.5 seconds. ADS-B can also be employed at low altitudes and can be used to track planes on runways.
The hitch
One hitch, however, is that until the system catches wide acceptance, it will not be of any use because planes must have the device installed in order for other planes to detect it.
But proponents, including the FAA, say that the system will likely catch on.
"The transition to an ADS-B environment is going to be extremely rapid," Shapero said. "It will be equivalent to the move to GPS, which literally happened overnight."
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