What is the primary flight control surface for roll?

The primary flight control surface for roll is the ailerons. Located on the outer wings of an aircraft, ailerons work by moving in opposite directions to control the aircraft's roll about its longitudinal axis. When one aileron is deflected upward, it reduces lift on that wing, while the opposite aileron, deflected downward, increases lift on the other wing. This differential lift causes the aircraft to roll towards the wing with the increased lift, allowing for controlled maneuvers and turns.

The other flight control surfaces, such as elevators, rudders, and flaps, serve different purposes. Elevators control pitch, affecting the nose of the plane moving up or down, while the rudder primarily controls yaw, affecting the direction the nose points left or right. Flaps are used to increase lift at lower speeds, particularly during takeoff and landing, but do not directly contribute to rolling the aircraft. Understanding the specific roles of these control surfaces is essential for effective aircraft operation and maneuvering.