Which action is recommended as part of retreating blade stall recovery?

• A. Reducing airspeed
• B. Increasing collective
• C. Maintaining current airspeed
• D. Increasing pitch

Answer: (A)

Retreating blade stall happens when the blade moving opposite the direction of travel (the retreating blade) can’t develop enough lift because of the dissymmetry of lift at high forward speeds. To recover, you want to lessen the rotor’s demand on the retreating blade, which is done by reducing forward airspeed. Lowering airspeed decreases the required angle of attack on the retreating blade and helps the rotor regain balanced lift, letting control be restored.

Increasing collective or increasing pitch would raise the blade angle of attack and disk loading, making the stall worse. Maintaining current airspeed won’t alleviate the stall.