Abstract: A short paper has been presented to show the phenomenon that the aircraft windshield wiper is blown away from the parking position during the flight. This behaviour has effect on the vision of pilots and copilots, and significantly impacts the flight safety. A windshield wiper was taken as the present study object. Hybrid structured-unstructured grids were adopted for the simulation. Structured grids were used around the fuselage, and unstructured grids were on the wiper framework. An interface was used to combine these two parts, and to generate the final calculation grid. Fluent code was employed to simulate fluid dynamics over windshield wiper. Numerical simulations were carried out based on N-S equations and S-A turbulence model. The incompressible flow parameter was handled by time-averaged method. The aerodynamic forces of the windshield wiper were calculated for several flight states at parking position with different angles and shapes. According to the comparison and analysis, the simulation results indicate that the airflow on the windward surface can be effectively guided by a reasonable parking angle and the spoiler on the wiper arm. This phenomenon consequently decreases the aerodynamic forces. The optimized proposal has been validated by flight test, provided theoretical support for the pre-tightening force and parking position.