What is the angle of attack?

The angle of attack is defined as the angle between the wing's chord line and the direction of the relative wind. This measurement is crucial in aerodynamics because it determines how the airflow behaves over the wing and directly affects lift generation. When the angle of attack increases, lift increases up to a certain point, beyond which it can lead to stall conditions. It's essential for pilots to understand this relationship as managing angle of attack is key to safe flight operations.

The other options, while they mention different angles, do not accurately define the angle of attack. The angle between the aircraft's wings and the horizon pertains more to pitch attitude rather than the aerodynamic interaction of the wing with the airflow. The angle of descent during landing relates to the approach path rather than the aerodynamic principles affecting lift. Lastly, the angle of incidence is a design parameter of the aircraft and does not vary with flight conditions, making it different from the dynamic nature of angle of attack. Understanding this concept is vital for effective aircraft handling and performance assessment.