A stall results from a rapid decrease in lift caused by airflow separation from the wing surface after exceeding the critical angle of attack.

A stall results from a rapid decrease in lift caused by airflow separation from the wing surface after exceeding the critical angle of attack.

• A. Stall
• B. Flutter
• C. Buffet
• D. Mach tuck

Answer: (A)

The main concept tested is that stall occurs when the wing’s angle of attack exceeds a critical value, causing the airflow to separate from the wing surface. When the flow can no longer stay attached, a turbulent wake forms, the lift produced by the wing drops sharply, and drag increases. This separation is what makes the lift curve peak and then fall off as you push past the critical angle of attack, so the wing no longer sustains the same lift. This is not flutter, which is a dynamic aeroelastic vibration of the structure; it’s also not buffet, which refers to unsteady pressure fluctuations often seen near transonic speeds; and it’s not Mach tuck, a high-speed phenomenon where the nose tends to pitch down due to shifts in aerodynamic forces. The description given matches stall: a rapid lift decrease caused by flow separation after surpassing the critical angle of attack.

The main concept tested is that stall occurs when the wing’s angle of attack exceeds a critical value, causing the airflow to separate from the wing surface. When the flow can no longer stay attached, a turbulent wake forms, the lift produced by the wing drops sharply, and drag increases. This separation is what makes the lift curve peak and then fall off as you push past the critical angle of attack, so the wing no longer sustains the same lift.

This is not flutter, which is a dynamic aeroelastic vibration of the structure; it’s also not buffet, which refers to unsteady pressure fluctuations often seen near transonic speeds; and it’s not Mach tuck, a high-speed phenomenon where the nose tends to pitch down due to shifts in aerodynamic forces. The description given matches stall: a rapid lift decrease caused by flow separation after surpassing the critical angle of attack.