Airplanes May Soon Crisscross the Skies Unfettered by FAA Lane Restrictions
The Federal Aviation Administration is working on an extraordinary solution to crowding in the skies: letting airlines and pilots set their own paths.
Under the ``free flight″ system, airlines _ instead of air-traffic controllers _ would choose the best routes given wind and weather. Specialized equipment would alert controllers and pilots to potential accidents, allowing planes to fly closer together. Though free flight for all planes is at least five years away, airlines already are setting flight paths for high-altitude flights _ where there is little congestion _ between 100 pairs of cities.
``Free flight could be one of the most significant developments in aviation since the development of the radio,″ said James K. Coyne, president of the National Air Transportation Association, a trade group, in congressional testimony last summer. But can what sounds like a recipe for chaos really be safe? ``If Mrs. Jones from Toledo sees another airplane half a mile off the wing, she might get worried,″ says Mike Connor, director of safety and technology for the National Air Traffic Controllers union.
But aviation regulators insist safety won’t be compromised. ``Free flight certainly isn’t a free-for-all,″ says Richard Taylor, a consultant heading an FAA-authorized task force on it. ``It’s disciplined in every aspect.″
The new system is needed because the existing air-traffic system can’t safely accommodate the predicted 60 percent jump in domestic air traffic over the next decade to 800 million passengers a year, the FAA says. Already, planes are subject to long delays on the ground and expensive holding patterns before landing.
There is plenty of unused room in the air, free-flight proponents say. The problem, they say, is that an antiquated traffic system creates congestion by limiting planes to skinny _ and now crowded _ paths in the sky.
The FAA-mandated lanes, charted decades ago, can be circuitous. By picking direct paths for nearly 100 flights over eight hours, one airline saved 86,412 pounds of fuel, valued at about $7,300, and nearly seven hours of flight time, the FAA says.
Funneling aircraft into the narrow authorized routes is particularly troublesome at busy airport hubs. Controllers often line up planes at slow, gas-guzzling speeds before clearing them to land. UAL Corp.’s United Airlines estimates that its annual costs for circling airports, being held at gates, flying at inefficient altitudes and taking indirect routes add up to $670 million.
Together, these things cost U.S. airlines an estimated $3.5 billion a year. ``This is the No. 1 controllable expense facing the airline industry,″ says Michael Baiada, president of RMB Associates, an aviation consulting firm in Evergreen, Colo.
Two technological elements for free flight already are in place. One, designed to prevent midair collisions, began going into cockpits in the late 1980s. The Traffic Alert and Collision Avoidance System warns a pilot whenever another aircraft flies nearby; then it issues evasion commands. The system has already prevented some close calls, but controllers say it also has raised false alarms that nearly caused accidents.
The free-flight system also will take advantage of the Global Positioning System, the satellite-based navigation system developed by the Defense Department. With the system’s location coordinates, controllers’ computers on the ground will be able to keep track of planes more precisely. In a big step toward free flight, the FAA last week said it plans to spend $475 million to develop a nationwide network of ground stations to receive navigation data from satellites and transmit it to aircraft. The FAA will gradually decommission older ground-based navigation equipment with plans to switch over to the GPS by 1998.
Thus planes will be able to fly flexible routes while remaining safe, free-flight proponents say. ``People tend to think safety comes from order,″ says Capt. William Cotton, manager of air-traffic and flight systems for United Airlines. ``But it is a big sky.″
Airlines will still have to file flight plans in advance with controllers, who can veto anything that might jeopardize safety. And controllers will clear planes for takeoff and landing, keeping a running list of which planes to expect at the airport at specific times.
Still, pilots and controllers say they need new and upgraded equipment before free flight can be expanded into busier areas such as lower altitudes and airport areas. The Air Line Pilots Association union wants to see an ``airborne situation display″ in planes, says John O’Brien, director of engineering and safety. Such a device would give pilots a screen to monitor any planes in the vicinity.
Meanwhile, the controllers, who have complained bitterly about recent slip-ups by existing radar equipment, are awaiting computers to help track the speed and flight paths of arriving aircraft.
Accurate projections of landing times, to within five seconds, will allow controllers to clear more planes for arrival. Airports in Denver and Dallas may begin testing models by year end.
The FAA expects to have a roll-out schedule for free flight by October. Airlines are urging a quick phase-in of free flight, but critics want a gradual shift over ten or more years, so that technology can keep up.
Limited free flight has caused some glitches earlier this year, controllers say. Currently, planes traveling as low as 29,000 feet can fly free. Planes over Chicago, Cleveland and Indiana have recently produced ``sector overloads,″ meaning that more planes slipped into a portion of airspace than controllers estimate they can safely monitor with existing radar. When that happens, controllers temporarily reroute incoming planes.
Scientists at Mitre Corp., an aviation-research company in Arlington, Va., say more work must be done to ensure that planes can be shifted safely from free flight en route to the controlled paths they need for landing.
In computer simulations of free flight, Mitre researchers have seen a ``merging″ problem, in which more planes arrive to land at once than airports can handle.
``We currently have no way to predict where or when a plane is going to just show up,″ under free flight, says Mr. Connor, the safety official for the controllers union. ``The problem is they still can all arrive at a place without a lot of concrete to put the planes down.″