Flight mechanics is the application of Newton’s laws (F=ma and M=I ) to the study of vehicle trajectories (performance), stability, and aerodynamic control. There are two basic problems in airplane flight mechanics: (1) given an airplane what are its performance, stability, and control characteristics? and (2) given performance, stability, and control characteristics, what is the airplane? The latter is called airplane sizing and is based on the definition of a standard mission profile. For commercial airplanes including business jets, the mission legs are take-off, climb, cruise, descent, and landing. For a military airplane additional legs are the supersonic dash, fuel for air combat, and specific excess power. This text is concerned with the first problem, but its organization is motivated by the structure of the second problem. Trajectory analysis is used to derive formulas and/or algorithms for computing the distance, time, and fuel along each mission leg. In the sizing process, all airplanes are required to be statically stable. While dynamic stability is not required in the sizing process, the linearized equations of motion are used in the design of automatic flight control systems.

David G. Hull Fundamentals of Airplane Flight Mechanics