Abstract: Pilot induced oscillation （PIO） is a kind of aircraft pilot coupling （APC） events with undesired, largescale and oscillatory characters. Detector can identify PIO events by the signals of aircraft. The key technology of design fuzzy logic detector for PIO events is the choice of fuzzy variables and design of fuzzy inference system, and fuzzy variables are described by some membership functions. In terms of analyzing and deducing the flight’s characters of PIO and fuzzy variables changing range, the membership functions are designed and the adaptability and influence of membership functions are analyzed. The results show that the fuzzy logic PIO detector designed by this method can identify PIO events.

Key words: aircraft pilot coupling, PIO, fuzzy logic, membership function, detectors