Roll is defined as the movement about which axis?

Roll is defined as the movement about the longitudinal axis of an aircraft. This axis runs from the nose to the tail and is crucial for understanding how an aircraft maneuvers in three-dimensional space. When an aircraft rolls, one wing moves upward while the other wing moves downward. This motion is primarily controlled by the ailerons, which are located on the trailing edges of the wings.

Understanding the longitudinal axis is essential for pilots and aerodynamicists, as it affects how an aircraft turns and responds to control inputs. Roll is one of the three primary rotational movements in flight, alongside pitch (movement about the lateral axis) and yaw (movement about the vertical axis). Recognizing the importance of the longitudinal axis in roll helps in various applications, including flight training and the design of flight control systems.