Abstract: According to the essence of Pilot Induced Oscillation (PIO) and the theory of Closed-loop control, the mathematical model of Pilot-Plane system is set up. Take a fighter trainer as an example, its PIOs are calculated in time-domain, and their results are compared with those obtained from the frequency-domain method. The results show that time-domain method is not only visualized but also is very clear in physical meaning. Moreover a lot of nonlinear elements are also easy to be considered. Its result may be more reliable.

Key words: polit induced oscillation, flying-quality, pilot-plane system