Spoiler (aeronautics)

Most often, spoilers are hinged plates on the top surface of a wing that can be extended upward into the airflow to spoil the streamline flow.

However, flight spoilers are routinely referred to as "speed brakes" on transport aircraft by pilots and manufacturers, despite significantly reducing lift.

The spoilers also cause a significant loss of lift so that there is more weight acting on the landing gear, allowing more braking to be used without skidding.

Some aircraft use spoilers in combination with or in lieu of ailerons for roll control, primarily to reduce adverse yaw when rudder input is limited by higher speeds.

In the case of a spoileron, in order for it to be used as a control surface, it is raised on one wing only, thus decreasing lift and increasing drag, causing roll and yaw.

Eliminating dedicated ailerons also avoids the problem of control reversal and allows flaps to occupy a greater portion of the wing trailing edge.

The British Aerospace 146 is fitted with particularly wide-span spoilers to generate additional drag and make reverse thrust unnecessary.