Which flap increases camber and wing area by sliding backward before deployment, enabling lower-speed flight?

• A. Fowler flap
• B. Plain flap
• C. Split flap
• D. Slotted flap

Answer: (A)

Flaps that increase lift at lower speeds do so by changing both the camber and the wing area. The Fowler flap stands out because it slides backward along tracks before deployment, which extends the flap rearward and outward. That motion increases the wing area as part of the flap surface and also increases camber when the flap is down, giving a much larger lift increase for a given approach or takeoff speed. This combination allows the airplane to fly slower without stalling, improving takeoff and landing performance.

Other flaps mainly change camber or use gaps to improve lift without adding much, or they primarily deflect downward without extending the wing surface, so they don’t provide the same level of lift increase at low speeds.