How do Vref and Vapp change with weight at landing?

• A. Heavier weight decreases both Vref and Vapp.
• B. Heavier weight increases Vref but decreases Vapp.
• C. They do not change with weight.
• D. Heavier weight increases both Vref and Vapp.

Answer: (D)

When weight goes up, the wing must generate more lift to support the airplane, so the stall speed increases (roughly with the square root of weight for a given configuration). Vref is tied to that stall speed in the landing configuration, usually with a safety factor, so Vref increases as weight increases. Vapp, the final approach speed, is typically Vref plus a fixed margin for gusts and stability; therefore it also increases with weight. In short, heavier weight raises both Vref and Vapp, while lighter weight lowers them.