An airplane will stall at the same angle of attack regardless of its attitude relative to the horizon.

• A. True
• B. False
• C. Only in clean configuration
• D. Only in a turn

Answer: (A)

Stall is caused by reaching the wing’s critical angle of attack, not by where the airplane’s nose is pointed. The angle between the wing’s chord line and the oncoming airflow (the angle of attack) determines when the airflow separates from the wing and a stall begins. For a given wing configuration, this critical angle of attack is essentially fixed, so the stall occurs at roughly the same angle of attack regardless of how the airplane is oriented to the horizon.

What attitude does change is the flight conditions around that stall. In a banked turn, you need more lift to hold a turn, so you fly faster to keep from reaching the same critical angle of attack; the stall speed rises. The actual angle of attack at which stall occurs, however, remains about the same for the wing and configuration. Flaps, slats, or gear change can shift the exact Cl_max and thus the exact AoA at stall, but attitude alone does not. This is why the statement is true.