Abstract: Constant Mach/CAS descent is an efficient profile descent procedure which conforms to the operational properties of pilots. It can be used to the four-dimensional (4D) guidance and flight management of aircraft entering into terminal airspace. This paper gives a research on the computation and synthesis techniques of this 4D flight profile. Its constitution and structure characteristics are first analyzed. A numerical integration algorithm and a simplified algebraic algorithm are then presented for its computation. For time-control, two parameters are introduced to describe its speed profile, which can enlarge the time-control range, and the associated iteration process and algorithm to determine the speed profile for a given flight time requirement are developed. Finally, digital simulation is done for a Boeing-707 aircraft model, and satisfactory results are obtained.

Key words: four-dimensional guidance, flight management, air traffic control, trajectory synthsis