What is the effect of deploying flaps on stall speed and approaching configuration?

• A. Flaps increase stall speed and decrease drag.
• B. Flaps increase lift at lower speeds, reducing stall speed; they also increase drag and steepen approach.
• C. Flaps have no effect on stall speed.
• D. Flaps decrease lift and increase stall speed.

Answer: (B)

Extending flaps changes the wing’s lift and drag characteristics. Flaps increase the wing’s camber and effective lift coefficient, so the airplane can fly at a given speed with more lift. That means the stall occurs at a lower speed, i.e., stall speed decreases. At the same time, extended flaps increase drag, both parasite and induced, so the aircraft will slow faster and descend more readily without gaining speed. This higher drag lets you achieve a steeper approach angle at the same approach speed, which is why flaps are used to make a steeper, controlled approach during landing.

So, flaps let you fly slower safely (lower stall speed) and increase drag to enable a steeper approach.