Which type of flap extends from the fuselage to the aileron on each wing and is electrically actuated, rotating on a simple hinge?

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

Answer: (A)

The lift increase at lower speeds comes from a flap that changes the wing’s camber by deflecting a portion of the trailing edge. A plain flap is a single, continuous panel that hinges along the trailing edge from the fuselage out to the aileron, rotating on a simple hinge and typically actuated by electric means. This matches the description: a straightforward, one-piece flap that spans from the wing root to the outboard end and uses a basic hinge mechanism. Other flap types involve more complex movement or geometry—split flaps deflect in two pieces on the lower surface, slotted flaps add a gap to energize the airflow, and Fowler flaps slide backward on tracks to increase wing area—so they don’t fit the stated simple, hinge-only, full-span configuration as neatly.