What is the airspeed threshold for speed brakes to automatically retract during flight?

The correct answer is that the airspeed threshold for speed brakes to automatically retract during flight is below 180 knots. This value is significant because it ensures the safe management of the aircraft's aerodynamics during critical phases of flight, particularly when lower airspeeds could lead to a stall condition.

At higher speeds, deploying speed brakes allows for more effective deceleration and descent without compromising the stability of the aircraft. However, once the airspeed drops below 180 knots, the potential for increased aerodynamic drag and the risk of stall phenomena increases, hence the automatic retraction of speed brakes serves as a protective measure to maintain control and performance.

Accordingly, this threshold is designed in conjunction with the aircraft’s flight envelope to safeguard operational safety and performance efficiency during different flight maneuvers.