What are the ailerons and how do they function in flight and during takeoff/landing?

• A. They are commanded symmetrically to produce yaw in flight.
• B. They are located on the inboard wing trailing edge.
• C. In flight commanded asymmetrically to produce roll; during takeoff/landing deflect symmetrically with trailing edge up to 45 degrees, trailing edge flap down to change lift; located on the outboard trailing edge.
• D. They serve as stabilizers.

Answer: (C)

Ailerons are control surfaces on the trailing edge of the wings that create roll by changing lift on the two wings differently. They’re mounted on the outboard trailing edge. In flight, they are commanded asymmetrically—one goes up while the other goes down—so one wing generates more lift and the other less, tipping the aircraft about its longitudinal axis. Yaw, in contrast, is produced by the rudder, not the ailerons, so they don’t control yaw. For takeoff and landing, flaps are extended to increase lift at low speeds; the ailerons can deflect symmetrically with the flaps to boost overall lift without inducing a roll, or work together with the flap system as designed on the aircraft. This combination—outer trailing-edge location, asymmetric deflection in flight for roll, and symmetric deflection with flaps during takeoff/landing—is why this option is the best description.