Study of aircraft stability margin criterion

A flying quality evaluation method——aircraft stability margin criterion is presented and verified with the simulator test data of an advanced combat.The definition, limiting boundary, and computation process is discussed.The results of this method are compared to those from the low order equivalent system matching and Neal Smith criterion. It is concluded, that the aircraft stability margin criterion can comprehensively evaluate the longitudinal maneuvering characteristic of airplane, and show good correlation to the Neal Smith criterion. So it can be applied to find the flying quality defects that may result in the PIO tendency.