FAA Sport Pilot Airplane (SPA)Aircraft Performance and SystemsHard
An airplane's maneuvering speed (VA) is published as 105 knots at its maximum gross weight of 1,600 pounds. If the airplane is being flown at a reduced weight of 1,300 pounds, what is the approximate new VA?
- A105 knots
- B115 knots
- C85 knots
- D95 knots
Show answer & explanationAnswer & explanation
Correct answer: D. 95 knots
Maneuvering speed varies with the square root of the weight ratio: VA(new) = VA(old) × √(W_new/W_old) = 105 × √(1,300/1,600) = 105 × √0.8125 ≈ 105 × 0.901 ≈ 95 knots.
Why the other options are wrong
- A. Incorrect — this assumes VA does not change with weight, which is false.
- B. Incorrect — VA decreases, not increases, at lighter weights.
- C. Incorrect — underestimates the new VA using an overly steep reduction.
Maneuvering Speed (VA) and Weight
VA is the maximum speed at which full, abrupt control deflection can be used without exceeding the airplane's structural limits; it decreases as aircraft weight decreases.
- VA is published for maximum gross weight
- At lighter weights, actual VA is lower than published VA
- Formula: VA(new) = VA(old) × √(weight new ÷ weight old)
Memory trick: Lighter airplane, lower VA — less weight needs less speed to stall protectively