In terms of flight test, the aerodynamic data of the aircraft after icing are identified mainly through the aircraft icing test flight data. However, due to the complexity of the flat tail flow field and the influence of the wing flaps on the downwash of the flat tail, it is difficult to determine the boundary of the flat tail stall. For a Twin Otter aircraft, when the flap deflects more than 30В°, the flat tail stalls from the leading edge, causing the aircraft to be out of control. Since 1994, NASA had conducted research on tail icing for three years and pointed out that the flat tail icing is the cause of abnormal elevator efficiency. In 2001, Frank and Abdollah compared the stall angle of attack and the maximum lift coefficient of the wing and found that when the angle of attack of the wing is between 0В° and 11В°, the change in the maximum lift coefficient is in linear relationship with the lift coefficient after icing. Under severe icing conditions, the stall angle of the aircraft decreases, and the stall speed increases. The main cause of flight accidents caused by airplane icing is the loss of control caused by the airplane stall. The case of icing flight in altitude hold and roll hold modes shows that flying in the autopilot mode under severe icing conditions is very dangerous and is prone to cause the aircraft to stall. As the degree of icing increases, the throttle skewness and the negative deflection angle of the airplaneвЂ™s level flight requirements continue to increase. The analysis results show that, under icing conditions, in the range of small angles of attack, icing has no obvious influence on the aircraft mode. The closed-loop simulation system of the altitude holding mode and roll attitude holding mode is used to calculate and analyze the flight quality changes of the aircraft after the wing surface is frozen. The aerodynamic equation of the airplane after icing is established, and the modal analysis of the airplane under different icing conditions is completed through the linearization of the flight equation. The two-dimensional interpolation method is used to improve the model of the aircraftвЂ™s stall area, which is mainly divided into the correction of the lift-drag coefficient linear area and the stall area and the correction of the aircraft stability derivative and the control derivative. This paper takes the icing data of the NACA 23012 airfoil as an example, establishes an icing influence model for real-time simulation based on icing time and aircraft angle of attack, and analyzes the influence of different icing geometry on aircraft characteristics. Icing has now become an important factor endangering flight safety.

Airfoil lift