Abstract: The model of three-dimensional low-altitude windshear with turbulence is systematically established, its threat to helicopter flight safety is comprehensively analyzed. A windshear model composed of microburst and atmosphere turbulence is developed. Without increasing the amount of calculation, a helicopter flight dynamic model integrated with wind velocity and windshear items is proposed, which optimizes the simulation precision of helicopter dynamic response through the windshear. Then a flight control system with attitude holding is synthesized into this model to correspond to the general helicopter flight state and to improve the response performance of helicopter. Following this, based on the characteristics of the windfield model, various flight velocities and windfield positions are selected and analyzed their relation between state changes and windfield. From the aspect of dynamics, the formula of response is derived theoretically with the vertical channel as the example. The results show that the turbulence mainly induces high frequency attitude response, while the windshear plays a dominant role in flight state influence, and the vertical downwind is the main inducement of threat. Based on the results, suggestions to avoid the windfiled threat are proposed.

Key words: windshear, microburst, atmosphere turbulence, threat analysis, flight dynamics modelling, dynamic response