An aircraft's movement around the longitudinal axis is controlled by which control surface?

The movement of an aircraft around the longitudinal axis, which runs from the nose to the tail of the aircraft, is controlled by the ailerons. These control surfaces are located on the outer part of each wing and function by altering the lift generated by each wing. When one aileron is deflected upward, the lift on that wing decreases, causing it to drop. Conversely, when the opposite aileron is deflected downward, that wing generates more lift, causing it to rise. This differential lift results in the aircraft rolling to the right or left, which is the primary function of the ailerons in controlling roll about the longitudinal axis.

Other control surfaces, such as elevators and rudders, primarily manage pitch (up and down movement) and yaw (left and right movement), respectively. Flaps are deployed to increase lift during takeoff and landing but do not play a role in controlling movement around the longitudinal axis. Hence, the role of ailerons is specifically crucial for roll control during flight.