What happens when the airflow exceeds the critical angle of attack?

• A. The airflow remains smooth and lift continues to increase.
• B. The airflow separates and becomes turbulent.
• C. Drag drops to zero.
• D. The wing stalls immediately.

Answer: (B)

When the angle of attack goes beyond the critical value, the air can no longer stay attached to the wing’s upper surface. The flow encounters an increasingly strong adverse pressure gradient, causing the boundary layer to separate from the wing. Once separation occurs, the flow in the separated region is typically turbulent and creates a large wake. This breakdown of attached flow destroys the lift-building effect, so lift stops increasing and then decreases, while drag rises sharply. That combination is what we describe as stall.

So this choice best describes what happens: the airflow separates and becomes turbulent, leading to a loss of lift. The other ideas—flow staying smooth with lift continuing to rise, drag dropping to zero, or the wing stalling immediately—don’t reflect how stall actually develops and manifests.