Which pair represents the two primary control surfaces on the wing?

• A. Rudder; Elevators
• B. Spoilers; Slats
• C. Ailerons; Flaps
• D. Ailerons; Rudders

Answer: (C)

The main idea here is which surfaces are mounted on the wing to directly influence its behavior in normal flight. The two primary wing surfaces are the ailerons and flaps. Ailerons are hinged on the trailing edge and are used to control roll by creating more lift on one wing than the other, tilting the aircraft sideways. Flaps are also on the trailing edge but closer to the fuselage; they increase the wing’s curvature (camber) to produce more lift at lower speeds, which is especially important during takeoff and landing.

The other options mix surfaces that aren’t both on the wing. Rudder and elevators are controlled on the tail and govern yaw and pitch. Spoilers and slats aren’t the primary wing-control pair; spoilers alter lift and drag to assist speed control or descent, and slats are high-lift devices at the leading edge. A combination involving the rudder isn’t a correct pairing for wing controls, and one option combines two wing surfaces that aren’t both primary wing controls.

So, the two primary wing control surfaces are the ailerons and flaps.