Define the term “stall” in helicopter flight.

In helicopter flight, the term “stall” refers specifically to a condition where the rotor blades exceed the critical angle of attack. When this happens, airflow over the rotor blades becomes turbulent, leading to a significant reduction or loss of lift. This phenomenon is analogous to an airplane stall, where the wings reach an angle where they can no longer generate sufficient lift.

Understanding the critical angle of attack is vital, as it marks the threshold beyond which the rotor's efficiency is compromised. In a stall situation, pilots can experience a loss of control if corrective actions aren't taken promptly, as the rotor system struggles to produce the necessary lift for sustained flight. Recognizing the signs of an impending stall is essential for pilots to maintain safe and effective flight.