Abstract: The flight safety of an aircraft is often seriously affected by wind and rain. The method based on momentum theorem to compute the force and moment generated by raindrops considering aircraft characteristics, flight and meteorologic conditions is provided. The impacts of rainfall with wind on the aerodynamic characteristics of an aircraft are studied. And the aircraft flight dynamic equations in rain and wind fields are deve-loped. By introducing a pilot model, the flight dynamic characteristics of an aircraft in the rain and wind fields are numerically simulated. The study shows that the balance attack angle of an aircraft will increase in the rainfall since the lift decreases and the drag increases, which will threaten the aircraft flight safety. When a rain is accompanied by a wind, the attack angle of the aircraft will be changed by the wind, and the aircraft will be more possibly to stall, which may cause a flight accident. The ability of the aircraft to fly safely in a wind will decrease due to rain.

Key words: flight safety, flight simulation, aircraft, rain, wind, momentum of raindrops