ABSTRACT
The chapter introduces the notion of stability via examples of first-order and second-order systems. Concept of ‘dynamic stability’ introduced in this chapter is identical to the ones commonly used in engineering analysis and widely accepted in aircraft flight dynamics; it is shown that the popular notion of stability in flight mechanics ‘static stability’, which is restricted, is derived from ‘dynamic stability’. The notion of dynamic stability is illustrated via example of perturbed pitch dynamics of aircraft around a level flight trim condition. A physics-based remodelling of pitch damping derivative is introduced, following which, an approximation for the short-period dynamic mode of aircraft is derived. Additionally, forced response of linear systems with example of pitch response to elevator control is presented.
