A Collision Model for Fixed-wing Aircraft over Highways Considering Visual Blind Zones

To address the problem of the negative influence of visual blind spots on pilots'judgment of safe distances during emergency road landings of small fixed-wing aircraft, thereby increasing the probability of collisions with ground vehicles, this study constructs a low-altitude aircraft-ground vehicle collision model considering visual blind spots and uses SA60L as a research object. It quantitatively analyzes the effects of multiple factors on collision risks. Based on the landing characteristics of the SA60L aircraft, a three-dimensional visual blind spots model for the visual landing process is established. A three-dimensional coordinate system is constructed by using the pilot's position as the base point and combined with a 20° downward visual angle constraint to determine the projection range of the visual blind spots on the ground. Collision scenarios are classified into two categories by integrating parameters such as vehicle drivers'reaction time, thus a collision probability model is established. For collisions with rear vehicles, collision probability formulas are derived from three states: no braking, speed not reduced to 0 after braking, and speed reduced to 0 after braking. For collisions with front vehicles, the collision probability calculation logic is established under the conflict conditions that the aircraft landing roll distance covers the front vehicles. The three-dimensional visual blind spots are used as a pre-constraint for probability calculations, and the computation using the Monte Carlo method is activated to conduct 10, 000 simulations only when ground vehicles enter dangerous areas. These simulations analyze how ground vehicle speed, traffic flow, aircraft near-ground speed, and landing altitude affect collision risk and construct a multiple linear regression model. The results indicate that ground traffic flow (t =15.78) and ground vehicle speed (t =9.25) have the most significant impact on collision probability, with both factors showing approximately linear positive correlation with collision probability and increasing ground vehicle speed leads to an increase in collision probability amplitude. Landing altitude has a nonlinear"first increase then decrease"effect on collision probability. A high-risk zone is formed when ground vehicle speed exceeds 80 km/h and landing altitude is below 200 m, where collision probability increases from 0.12 in the safety threshold zone (speed < 40 km/h and altitude > 200 m) to 0.27, representing a 2.3-fold increase. The determination coefficient of the multiple linear regression model is R² =0.965, indicating good fitting and significance.