FAA Flight Instructor Airplane (FIA)Aerodynamics and Principles of FlightMedium
A CFI explains to a client that flying at or below maneuvering speed (Va) protects the airframe during turbulence or abrupt control inputs. Why does this protection occur?
- AVa guarantees the airplane cannot be damaged regardless of how many or how abrupt the control inputs are
- BFlying at or below Va prevents the airplane from ever approaching its never-exceed speed (Vne)
- CVa is a fixed airspeed that does not change with the airplane's gross weight
- DAt or below Va, the wing will stall before the load factor can exceed the airplane's structural limit load factor
Show answer & explanationAnswer & explanation
Correct answer: D. At or below Va, the wing will stall before the load factor can exceed the airplane's structural limit load factor
Maneuvering speed is the speed at which the wing will aerodynamically stall before generating enough lift to exceed the airplane's certificated limit load factor, thus protecting the structure. Va decreases as gross weight decreases, and it does not protect against repeated or combined control inputs.
Why the other options are wrong
- A. Wrong — full or repeated multi-axis deflections can still overstress the airframe even at Va
- B. Wrong — Va and Vne are separate limits; Va does not govern proximity to Vne
- C. Wrong — Va varies directly with the square root of weight and is lower at lighter weights
Maneuvering Speed (Va)
The maximum speed at which full, abrupt control deflection can be applied without exceeding the airplane's limit load factor, because the wing stalls first.
- Va decreases with decreasing gross weight
- Protection applies to a single abrupt control input, not repeated inputs
- Above Va, structural damage can occur before the wing stalls
Memory trick: 'Stall before you break' — Va lets the wing quit before the airframe does