The shortest distance between two points is a straight line, you mutter, staring at the road map, despairing at the kinks, bends and wobbles of America’s highway system. About then, an airplane soars overhead.
You envy the jet, which seems to connect those points with that straight line. Yet, the air routes twist and turn almost as much as the highways.
The National Airspace System directs planes in prescribed paths that resemble interstates in the sky. And, like highways, airways back up when too many planes want to go in the same direction at the same time.
“We have a problem,” said Robert W. Baker, executive vice president of operations for American Airlines, referring to flight congestion and the ability to deal with it. “The ability to change technology in one fell swoop in the system is impossible. This collaborative approach called `free flight’ is the only shot we have.” (Baker was talking about FAA attempts to simply swap old technology for new technology at air traffic control centers, a failed project that cost millions in the last 15 years.)
Airlines and the government consider free flight, which basically would allow pilots to choose the most efficient route and altitude, as the future of aviation.
“Free flight should be characterized as finding methods to safely remove existing restrictions to flight. Those restrictions are the things that reduce the capacity and flexibility that’s available to us now,” said Bill Cotton, manager of Air Traffic and Flight Systems for United Airlines.
“It would give pilots more control over choosing and changing the routes they fly and is a key part of our system modernization,” said Don Zochert, spokesman for the Federal Aviation Administration’s regional office in Des Plaines.
When airlines began passenger service in the late 1920s, pilots flew any route they chose, and they usually chose a beeline, within the navigational constraints of the time, which sometimes meant following roads. The sky was big enough to hold the few planes flying.
After World War II, commercial aviation launched an ever-increasing number of flights with pilots continuing to set their own courses. On June 30, 1956, a United Airlines DC-7 and a TWA Super Constellation collided over the Grand Canyon, killing 128 people, then the largest loss of life in domestic aviation. Another crash between a passenger plane and a military aircraft followed within a year.
That sparked public demand for reforms to reduce the chance of mid-air collisions. The resulting Federal Aviation Act of 1958 created the Federal Aviation Agency, which became the Federal Aviation Administration in 1967. The FAA was charged with developing and maintaining a common civil-military system of air navigation and air traffic control. The FAA formalized the air lanes planes use today.
Hundreds of lanes follow ground checkpoints, usually navigational radio beacons, confirmed by en-route air traffic control centers (as opposed to airports) around the country. Any number of planes can occupy an air lane, as long as they are 5 miles apart en route.
Fast-forward 40 years. Air-traffic congestion threatens to strangle aviation. According to FAA statistics, commercial air transport takeoffs and landings totaled 7.51 million in 1965, 12.08 million in 1975, 18.2 million in 1985 and 23.88 million in 1995.
Delays from the volume of traffic cost the airlines billions in fuel and aircraft and crew utilization, not to mention ill will when passengers arrive late. Airlines estimate the waste at $3.5 billion a year. Under the current system, delays will be measured in hours within 15 years from an average of 1.14 minutes now.
According to a conservative American Airlines computer projection, in 2014, that average delay will be 3.62 minutes under the current air-traffic system. Multiply these numbers by more than 30 million flight and the minutes add up. And the delays are averages. If 10 flights are “on-time,” 10 flights will be about 7 minutes late; if 20 flights are on-time, 20 will be about 14 minutes late.
The hub system would cease because passengers and airline crews would no longer be confident of making connections. Right now the minimum connection time at most airports is about 30 minutes. This lets airlines schedule many flights (called “banks”) in and out in a short period of time, allowing passengers quick connections, creating the hub.
If the hub system ceased, many fliers would pay considerably higher fares, and it would require more plane changes to reach certain destinations. The hub system also benefits cities such as Chicago, which is a major hub for the nation’s two largest airlines.
New technology and free flight could make the delays in 2014 less than 0.7 minutes. “The Mitre Corp., a consulting company that works with government, has 350 high-caliber scientists working on this for the FAA,” said American’s Baker, co-chairman of the Implementation Committee for Free Flight, which combines all facets of flying, including general and commercial aviation, pilots’ unions, aircraft manufacturers, the military, the FAA and the air-traffic controllers union.
Modern aircraft contain advanced avionics, the electronics that help the pilot fly. (Most older aircraft could be retrofitted with the new avionics.) Improved radar, computers and global positioning satellites help pilots and ground controllers pinpoint aircraft. Global positioning was made possible by the Defense Department, which launched 24 satellites in the last decade in 12-hour orbits creating the Global Positioning System. It takes four of those satellites to provide precise position, altitude and time. Though the Defense Department distorts the accuracy of the signals to prevent potential enemies from using the system, ground-based transmitters send a correction signal to aircraft, providing accuracy to within a few feet.
Soon after the turn of the century, radar, satellites and airplanes will send and receive data to and from computers. This data-link will eliminate misunderstandings caused by the spoken word (and possible failure of the voice channel) and allow each radio frequency to handle more information than one human voice, much the way a digital phone line can handle data and voice at once.
This would reduce direct reliance on the Air Traffic Control system and increase the efficiency of the present system. It also would allow free flight to expand globally. “It’s not less air traffic control. It’s better, much more precise air traffic control,” said United’s Cotton.
American, Delta, Northwest and United support free flight, in which they are dabbling with FAA approval. An aircraft flying above 29,000 feet and at least 200 hundred miles from its departure/destination airport can participate in the National Route Program, an element of free flight.
The program allows each airline to calculate the ideal route for each flight. Airlines can share information on this or go it alone. If, for example, American decides its aircraft should fly at 35,000 feet, and United at 37,000 feet, there’s no problem. The airlines would still file their flight plans with Air Traffic Control, ATC would continue to monitor flight paths and prevent conflicts and the airlines know the schedule of their competitors. Every major airline owns computers capable of optimizing flight plans.
With airlines no longer having to fly FAA-designated routes, it shortens a transcontinental trip by 5 to 15 minutes and saves money. Some estimates show this saved the airlines more than $40 million this year.
“Think of free flight as an umbrella in which we are going to change over many years from a command-and-control air-traffic system, where every change you make in speed, altitude and direction must be approved, to a system in which the air-traffic function serves as an alarm,” Baker said. “I do anything I want, and only when I come in conflict with another airplane is Air Traffic Control going to tell one of us to do something. The decisions as to where to fly and how high and all the rest transfer from the FAA to the cockpit. The technology, instead of being ground-based, will be airplane based.
“The FAA uses the OAG (Official Airline Guides, a privately published compilation of all of the world’s scheduled airline flights) for information,” Baker said. “All their computers are loaded with OAG information about what American is going to fly this afternoon. They don’t know that I already canceled a trip because of (an airplane breakdown) this morning. They don’t know I want to fly an extra section (an additional aircraft on a route) until I file the flight plan.
“The FAA makes decisions based on what they see out the window and a database that’s far from being up to date.”
Collaborative decision-making will give the FAA better information about what the airlines would like to do and keep the airlines better informed about the system’s capabilities, Baker said.
Free flight creates two airspace zones around an aircraft, based on its speed, performance and communications and navigation and surveillance equipment. The inner “protected zone,” of one plane must not meet the “protected zone” of another.
“The protected zone would be based upon the surveillance used,” said Cotton. “If it were radar, we wouldn’t change from what it is today. If we use Automatic Dependence Surveillance Broadcast, that’s based on the GPS satellite navigation system, then you can much more precisely pinpoint everyone’s location. Theoretically it’s possible to have airplanes safely separated that are a mile apart, instead of the 5 to 10 miles that exists now.”
To assure this, an outer “alert zone” extends much farther, and if it contacts another plane’s alert zone, the pilots and/or air traffic controller will determine necessary corrections. Thus, planes can fly freely until alert zones touch.
“The alert zone is more of a function of time than distance, depending on actual implementation,” Cotton continued. “It could be from one to two minutes before the closest point of approach.”
Air traffic controllers will decide what aircraft takes priority, or in emergencies, on-board equipment will order avoidance maneuvers. As technology progresses, course corrections may be sent via computer rather than human controller.
“We’re basically cautiously optimistic,” said Mike McNally, president of the National Air Traffic Controllers Association. “Free flight is designed to improve the efficiency of the system. Our job is to make sure we maintain the same level of safety as we improve efficiency.
“Our assessment is that free flight is going to increase the number of controllers needed in order to monitor the various systems that are going to be required to make free flight a reality.”
“I think the time frame is going to be a lot longer than a lot of people are hoping for,” said McNally. “There’s a lot of modernization projects involved, and many haven’t gotten off the ground yet. It’s going to be a very evolutionary type of event.”
The FAA operates a test system called User Request Evaluation Tool. According to the FAA’s Zochert, “It predicts potential conflicts, maybe 20 minutes into the future, based upon radar information and flight plan information.”
In free flight, the traffic management tool can help the controller decide whether there will be potential conflicts if, say, American Flight X flies at a specific heading at a specific altitude.
It’s being tested in two en-route air traffic control centers, Indianapolis and Memphis. At Indianapolis, which is in the Great Lakes Region, it is being used only in one airspace sector. “It’s a prototype system operating there for over a year and everything that we’ve seen from it is very, very positive, both in terms of its ability to predict potential conflicts and the way it’s being embraced by the controllers, who are the guinea pigs using it,” Zochert said.
Cotton said United is requesting an enhancement known as “local area augmentation” be installed at O’Hare. It will greatly improve the ability to create flight paths in and out of the airport, to continue landings in bad weather on all runways even if the existing ILS (instrument landing system) ground system fails. (The ILS commonly is out of service for maintenance, which limits O’Hare’s capacity. With GPS, the key to local area augmentation, the two systems will greatly improve reliability.)
Local area augmentation also includes the ability to have surveillance over not only airplanes, but also all ground vehicles, such as food trucks, cars, snow plows and crew buses that run around the airport. Since the control tower cannot always see service vehicles, this would reduce the incidence and risk of collisions between the service vehicles and taxiing aircraft.
“We’re hoping that over the next two or three years, we should see some major advances in the Chicago area, with some new tools for controllers and some new tools for pilots, that will increase safety first and then the reliability of operations,” said Cotton.
American’s Baker said his airline looks forward to a system that optimally spaces aircraft in landing patterns. Controllers now space planes 3 miles apart, even if they could be safely bunched closer together because they lack the information technology to integrate aircraft type and load with atmospheric conditions. An unnamed new system will use new technology such as lasers along the runways to provide this information to controllers.
“Each step we take toward a more flexible system of air traffic management is a step toward free flight,” said L. Lane Speck, director of FAA Air Traffic Program Integration. “Free flight is also safe flight. Every new procedure and technology that makes the system more flexible must maintain the high standard of safety enjoyed by American air travelers. As we move in this direction, we anticipate cost and efficiency benefits for consumers as well as carriers.”
