Which flap type is defined by moving aft along tracks when extended?

Which flap type is defined by moving aft along tracks when extended?

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

Answer: (C)

The motion described—moving aft along tracks as it extends—defines the Fowler flap. This design slides the flap backward on tracks while it extends, which increases both the trailing-edge area and the wing’s camber. That extra surface behind the original trailing edge boosts lift at lower speeds, useful for takeoff and landing. Other flap types don’t use that rearward track extension: plain flaps hinge down from the trailing edge, split flaps drop a lower surface without sliding along tracks, and slotted flaps create a gap between the flap and wing to energize the airstream rather than moving rearward along tracks.

The motion described—moving aft along tracks as it extends—defines the Fowler flap. This design slides the flap backward on tracks while it extends, which increases both the trailing-edge area and the wing’s camber. That extra surface behind the original trailing edge boosts lift at lower speeds, useful for takeoff and landing. Other flap types don’t use that rearward track extension: plain flaps hinge down from the trailing edge, split flaps drop a lower surface without sliding along tracks, and slotted flaps create a gap between the flap and wing to energize the airstream rather than moving rearward along tracks.