The stall angle of attack is the same regardless of gross weight.

• A. Increases with altitude
• B. The same regardless of gross weight
• C. Depends on density altitude
• D. Varies with bank angle

Answer: (B)

The key idea is that stall occurs when the wing’s lift coefficient reaches its maximum value, CL_max. That is a property of the wing’s shape and configuration, not how heavy the airplane is. The lift equation L = 0.5 ρ V^2 S CL shows that at stall, L must equal weight, so heavier weight means you must fly faster to reach the same CL_max. In other words, stall speed (the speed at which stall happens) increases with weight, but the angle of attack at which stall occurs—the angle that makes CL reach CL_max—stays essentially the same for a given wing setup.

Density altitude and altitude change air density, so they alter the speed you need to reach CL_max (stall speed in IAS or TAS), but not the actual angle of attack at which stall occurs. Bank angle changes the required load factor and can raise the speed at which stall occurs in a turn, yet the stall angle of attack remains roughly the same because it’s still governed by CL_max.