Spoilers and Ailerons

Hinged panels called spoilers on top of a wing serve the opposite purpose from flaps and slats. When a spoiler is raised, it spoils the wing’s aerodynamic shape, increases drag, and cuts the amount of lift. Spoilers are used to cut lift after an airplane has landed. They may be used to help a big, heavy plane turn. The spoilers on one wing are raised to help the ailerons.

Ailerons are panels in the trailing edge of an airplane’s wings that are used for turning the plane. One aileron tilts up, and the other tilts down. One wing produces more lift than the other and rises. The wing that produces less lift falls, and the plane rolls into a turn.

Big airliners often have two sets of ailerons. The ailerons closest to the wingtips have more leverage for rolling the plane at low speeds. At high speed, the ailerons closest to the fuselage have enough leverage to turn the plane.