What is the function of the ailerons on an aircraft?

Ailerons play a critical role in controlling an aircraft's roll, which is the movement around its longitudinal axis. When the pilot moves the control yoke or stick to the left or right, the ailerons on the wings respond by moving in opposite directions. One aileron deflects upward, while the other moves downward. This creates a difference in lift between the two wings: the wing with the upward-moving aileron experiences reduced lift, while the wing with the downward-moving aileron experiences increased lift. The resulting differential lift causes the aircraft to roll towards the wing with the upward-deflected aileron.

Understanding this function is crucial for pilots, as controlling roll is essential for maneuvers such as turns and maintaining level flight. The ailerons are primarily used in conjunction with the other primary flight control surfaces to provide a responsive control system, allowing pilots to effectively manage the aircraft's attitude and direction in flight. Additionally, while ailerons can indirectly affect the aircraft’s other movements, such as yaw and pitch, their primary function is strictly to facilitate roll.