3.3.1 Commercial flight procedures In a realistic civil aircraft flight, the complete trajectory is broken into series of flight segments, mainly broken into phases as shown in Fig. 9. Each of these phases in turn include several flight segments, where each segment can be defined by control objectives and termination conditions designed to be flyable. Mathematically, each flight segment can be described by two constant control variables selected from among engine thrust setting, Mach number or calibrated airspeed, and altitude rate or flight path angle [18].
Fig.9 Complete trajectory for an aircraft from takeoff to landing Furthermore, airline specifications often combine a number of segments in a specified order to form certain profiles. A lateral profile can be defined for an aircraft flying level and turning at constant bank angle using waypoints. Aircraft takeoff and descent is divided into a sequence of segments defining a vertical profile. Each vertical flight segment is defined by choosing exactly two control objectives, at most one from each category. This either explicitly or implicitly defines how the aircraft pitch and thrust are controlled. For example, choosing constant Mach and idle thrust defines a descent segment that control speed using aircraft pitch.
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