Airplanes And Aerodynamics Commercial Pilot Practice Test

Stall begins where the local angle of attack reaches the airfoil’s critical value, and for an untwisted rectangular wing the inner portion encounters that condition first. The flow over the wing changes from attached to separated when the local angle of attack becomes too large. In a simple rectangular wing with no washout, the inner section (near the root) tends to reach that critical state before the outer sections, so the stalled region starts at the root and then expands outward toward the tip as the overall angle of attack is increased. This pattern helps explain why the statement is true: stall initiates at the root and progresses toward the tip. The other conditions—supersonic speeds or turbulence dictating stall location—do not define the basic inboard-to-outboard progression on a rectangular wing.