What do speed brakes do on an aircraft?

Speed brakes are designed specifically to increase drag on the aircraft. When deployed, speed brakes alter the aerodynamic properties of the aircraft, causing a significant increase in drag, which helps to slow the aircraft down during descent or when needing to reduce speed quickly. This capability is essential for pilots as it aids in managing airspeed during landing approaches and other flight phases where controlled deceleration is crucial.

By increasing drag without adjusting engine power, speed brakes allow for more flexible and precise speed control, making them a vital tool in ensuring safe and efficient aircraft operation. This function is particularly important during landing and approach, where maintaining the appropriate speed is critical for a safe descent and runway alignment.