To retract the speed brake after extension, which conditions must occur?

• A. Flaps Extended
• B. PCL Advanced to MAX
• C. Both Flaps Extended and PCL Advanced to MAX
• D. No action; it auto retracts

Answer: (C)

When speed brakes are extended, they won’t automatically tuck away unless the aircraft is in a configuration that can safely accept a retraction. The system is set so that retraction occurs only if two conditions are met: the wings are in a high-lift state with the flaps extended, and the engines are producing maximum thrust (Power Control Lever advanced to MAX).

Why this combination makes sense is that retracting the speed brakes while flaps are still out and the aircraft is not at high thrust could destabilize the aircraft—there would be a sudden change in lift and drag at a moment when control is delicate. Requiring both conditions ensures you have enough lift to keep the wing stable and enough thrust to maintain safe airspeed after the drag device is removed. If either condition isn’t met, retraction isn’t permitted, preventing an abrupt or unsafe transition.