Final answer:
Flight spoilers must not be extended at airspeeds below the recommended approach speed to ensure adequate maneuver margins.
Step-by-step explanation:
Flight spoilers are used to decrease the lift and increase the drag on an aircraft, aiding in the control and stability of the aircraft during certain flight phases, such as landing or reducing speed quickly. To ensure adequate maneuver margins, flight spoilers must not be extended at airspeeds below the recommended approach speed.
The recommended approach speed is the speed at which the aircraft should be flying just before landing and it depends on several factors, including the aircraft's weight, configuration, and weather conditions. It is typically lower than the normal cruising speed and allows for a safe and controlled landing.
Spoilers can be used to "dump" lift and make the airplane descend; or they can be used to slow the airplane down as it prepares to land. When the airplane lands on the runway, the pilot usually brings up the spoilers to kill the lift, keep the plane on the ground, and make the brakes work more efficiently.