What are the four most common types of high lift devices?

• A. Leading edge flaps, trailing edge flaps, slats, and slots.
• B. Ailerons, elevators, and rudders.
• C. Vortex generators, spoilers, speed brakes, and canards.
• D. Landing gear, antennas, windows, and doors.

Answer: (A)

High lift devices are wing systems that raise lift at low speeds, such as during takeoff and landing, by increasing wing camber or modifying airflow to delay stall. The four most common types are on the leading edge and trailing edge of the wing. Leading edge devices include flaps that extend from the front edge to increase curvature and lift, and slats that move forward or extend to create a gap (a slot) that energizes the airflow over the wing at high angles of attack. Trailing edge devices are flaps that extend downward and rearward, increasing camber and sometimes wing area to boost lift further. These configurations—leading edge flaps, trailing edge flaps, slats, and slots—cover the primary ways wings are augmented to generate more lift during critical phases of flight.

Ailerons, elevators, and rudders are the main control surfaces for roll, pitch, and yaw, not for increasing lift at slow speeds. Vortex generators, spoilers, speed brakes, and canards don’t represent the four most common high lift devices; spoilers and speed brakes actually reduce lift, and while canards are lifting surfaces, they are not the standard set used for takeoff and landing lift enhancement. Landing gear, antennas, windows, and doors are structural or system components, not high lift devices.