Air Traffic Control Free Flight System Explained

Introduction

Free flight represents a positive change in the airline traffic management system. It promises efficiency and profitability to an industry that has been going through a difficult period.

The 1978 deregulation of airlines was perceived as a revolutionary change in the airline industry. Similarly, in the field of air traffic control, the free flight system promises to be the most important change since the introduction of radar in communication and aviation management. Rapid advancements in satellite technology have given tremendous impetus to the field of communication, and satellite-based navigation equipment promises to be the future of aviation control. The phenomenal growth in air traffic and the difficulties in regulating it have highlighted the shortcomings of the present air traffic control system. The American airline industry incurs a loss of approximately U.S. $3.5 billion annually due to inefficiencies in the current centralized air traffic control system. The Federal Aviation Administration (FAA) has already approved and begun implementing the free flight system in a phased manner. The sections below provide a brief overview of the free flight system and compare it with the present air traffic control system.

Current System and Its Limitations

With more than 50,000 flights taking to the skies every day, the present U.S. air traffic control system places increasing strain on control room staff, who are responsible for tracking, guiding, and directing pilots. Under the current system, air traffic controllers resolve conflicts in airspace using radar signals, regulating traffic by adjusting the altitude and speed of different flights. As James Coyne, president of the National Air Transportation Association, explains: "All of the information that flows to and from a pilot today in virtually all aircraft is done on a strictly single-voice channel, back and forth, with human beings actually saying all the words live. As anyone can imagine, that is an extremely inefficient way to convey data."

Pilots are dependent upon instructions from the control room to avoid conflicts and potential disasters in airspace. Once an aircraft is cleared by the departure controller and leaves the TRACON (Terminal Radar Control) airspace, it is monitored en route by personnel in the ARTCC (Air Route Traffic Control Center), who continue to provide the pilots with traffic, altitude, and speed instructions. For most airways, however, the stipulated altitude, route, and speed restrictions do not contribute to optimal efficiency.

The Free Flight System

Though the initial idea was conceived as far back as 1971 by William Cotton — often called the father of free flight — the free flight program was formally developed in 1995 by the RTCA (Radio Technical Commission for Aeronautics). With Charles Keegan as director of the program, the FAA accepted the system for implementation in 1998. The free flight system depends on more reliable and faster satellite-based tracking and positioning, unlike the current radar-based tracking system. In contrast to the present voice-based control model, free flight is based on a continuous exchange of digital information regarding flight positions — not only with control rooms but also with nearby aircraft. The automated surveillance and processing system, which is an integral part of the free flight scheme, would instantly identify and project the path of any flight, relieving control room staff of arduous, time-consuming mental calculations and paperwork.

The Radio Technical Commission for Aeronautics defines free flight as "safe and efficient flight operating capability under instrument flight rules (IFR) in which the operators have the freedom to select their path and speed in real time." The free flight system offers pilots considerably more freedom compared to the current system, in which they must strictly follow instructions from the control room. In free flight, control is essentially decentralized and traffic management is shifted from the control room to the pilots. However, all flights must be equipped with the avionics necessary for air traffic management.

Conclusion

Free flight is definitively the future of air traffic control. The present method of control is far too limited to handle increasing air traffic and congestion. Once implemented, the free flight system would greatly enhance the throughput and operational performance of the airways. Establishing a free flight system would, however, require not only the installation of new technological equipment — including redesigned cockpits — but also significant procedural changes.

Free flight involves increasing automation and decentralization of control. It would be prudent to carefully define the appropriate level of automation so that human complacency is avoided and better integration of automated systems with human participation is achieved. There is no doubt that once free flight avionics are thoroughly tested and approved for full implementation, it will signal the beginning of a new era and a paradigm shift in air traffic control and management.

Bibliography

1) Ken Kaye, "About Free Flight: History," accessed April 22, 2004, http://ffp1.faa.gov/about/about_article1.asp

2) Mica R. Endsley, "Situation Awareness, Automation & Free Flight," accessed April 22, 2004, http://atm-seminar-97.eurocontrol.fr/endsley.htm

3) CAASD, "CAPSTONE," accessed April 23, 2004, http://www.mitrecaasd.org/proj/capstone/overview.cfm

4) Mario S.V. Valenti Clari et al., "Cost Benefit Study of Free Flight With Airborne Separation Assurance," accessed April 23, 2004,

5) National Aerospace Laboratory, "Air Traffic Control: Aspects of Free Flight," accessed April 23, 2004,

6) Jacques Leslie, "Free Flight: The Solution to the Antiquated Air Traffic Control System?" accessed April 23, 2004,

7) Craig C. Freudenrich, Ph.D., "How Air Traffic Control Works," accessed April 23, 2004, http://electronics.howstuffworks.com/air-traffic-control.htm