The use of the word agility has represented a search for some undefined property of a system which accounts for the discrepancy between how a rotorcraft or an aircraft is flown and what performance metrics indicate can be achieved. A method is proposed which quantifies the maximum capability of change available to a dynamic system within a set of constraints. Instead of looking at the specific value of agility (delta maneuver state per time or change in maneuver rate per time), this paper focuses on possible magnitudes of dynamic parameters and their derivatives. The intent is to provide a means to examine how current levels of agility are being used and from that provide a data base which can be used to infer how much agility is needed. Aircraft equations are presented for body-axis pitch rate, stability-axis roll rate, normal load factor and their derivatives. These are constrained by stability, roll coordination, and flight control limiters.
