Which control surface is responsible for creating movement about the longitudinal axis?

The control surface responsible for creating movement about the longitudinal axis of an aircraft is the ailerons. Ailerons are situated on the outer portions of the wings and operate to control the roll of the aircraft. When one aileron is deflected upwards, the corresponding wing experiences less lift, while the opposite aileron, which is deflected downwards, increases lift on that wing. This differential lift results in a rolling motion about the longitudinal axis, which runs from the nose to the tail of the aircraft.

Understanding the role of ailerons is crucial for pilots because rolling is a fundamental maneuver necessary for banking the aircraft during turns, maintaining balance, and ensuring stability during flight.