On Flight Risk Analysis Method Based on Stability Region of Dynamic System Under Icing Conditions

The occurrence of loss of control in flight is often accompanied by deep coupling of flight parameters. In order to explore the mechanism of coupling induced flight risk, a method of flight risk assessment based on the stability region of a nonlinear dynamic system was proposed. The Monte Carlo method was improved to identify the boundary of the stability region, and the key parameters that can represent the flight safety were set. The risk quantification method and the colorized flight risk characterization method were proposed. Combined with the case of aircraft encountering icing, the variation trend of flight stability region and flight risk under different icing degrees was calculated. The results showed that with the aggravation of icing, the flight stability region was significantly reduced and the coupling of flight parameters was aggravated. And compared with the traditional angle of attack protection method, this method can find the potential flight risk earlier, and characterize the way of parameters' coupling and the flight risk evolution process. The proposed method can improve the pilot's situational awareness, and also provide theoretical support for the prevention of flight risk under adverse conditions, and provide reference for the further development of boundary protection control law.