Abstract: With the increasing size of civil aviation aircraft, the lateral thrust on the surface course is getting bigger and bigger because of the large weight and low speed when turning on the ground. The current pavement design specification, especially the asphalt concrete pavement design specification only considers the vertical force and ignores the lateral force, but the airport runway system has many corners, so it is necessary to consider the lateral force during the design process of these parts. And the method of front wheel manipulation turning is the main mode of civil aircraft ground turning. Because the aircraft will be influenced by complex forces in the ground turning process, which will be affected by the crosswind, pavement roughness, pilot control way and the plane speed and other factors, so in order to simplify the analysis, reasonable assumptions are made. It is considered that when the aircraft is in the low speed process of turning on the ground, the steering angle of the front wheel is constant. The instantaneous motion mode is circular motion whose radius is fixed. The simplified formula of the specific value of lateral and vertical force is obtained through analysis, which will make the lateral force calculation much easier, and it is found that the lateral force of wheels is not equal in the process of turning. For the model B737-800, the ratio of lateral and vertical force of the four tires of main landing gear is 1.33:1.29:1.04:1, and the lateral force of the outermost tire relative to the center of rotation is the biggest. The lateral force of the innermost tire is the smallest, a drop of 33% than that of the outermost tire.

Key words: aircraft ground turning, front wheel manipulation, lateral force, B737-800