TRUE/FALSE: When the onset of retreating blade stall is detected, an increase of collective is the easiest and quickest way to recover.

TRUE/FALSE: When the onset of retreating blade stall is detected, an increase of collective is the easiest and quickest way to recover.

• A. True
• B. False
• C. Not sure
• D. Depends

Answer: (B)

Retreating blade stall happens when the blade on the far side of the rotor disk reaches a critical angle of attack due to high forward speed and rotor loading. To recover quickly, you want to unload the rotor so the stalled retreating blade can reattach and lift is restored. Reducing collective lowers the rotor’s aerodynamic load and blade angle of attack, helping the stall break and control return. Increasing collective would add more lift and load, worsening the stall and delaying recovery. So the statement is not correct; the fastest recovery is achieved by reducing collective (and often reducing forward airspeed) rather than increasing it.

Retreating blade stall happens when the blade on the far side of the rotor disk reaches a critical angle of attack due to high forward speed and rotor loading. To recover quickly, you want to unload the rotor so the stalled retreating blade can reattach and lift is restored. Reducing collective lowers the rotor’s aerodynamic load and blade angle of attack, helping the stall break and control return. Increasing collective would add more lift and load, worsening the stall and delaying recovery. So the statement is not correct; the fastest recovery is achieved by reducing collective (and often reducing forward airspeed) rather than increasing it.