Flight management systems - What are they and why are they being developed?

This paper presents the motivation for developing and using flight management systems. The architecture and theoretical basis of these systems is presented and their typical operation during a flight is described. Two computer programs developed to support flight management research are used to obtain numerical results which illustrate significant potential reductions in fuel used and/or airline operating costs which can be achieved through use of flight management systems. The specific levels of savings depend on the nature of the air traffic control system in which the aircraft operates. Accordingly, results are presented both for operations in the existing air traffic control system and in an air traffic control environment with reduced restrictions on airplane operations. The capability of airplanes equipped with suitable flight management systems to operate in a time-based (4-D) environment is also discussed. Programs of the Federal Aviation Administration which may influence the operation of flight management system equipped aircraft in the evolving National Airspace System are also briefly reviewed.