Function of wing flaps in aircraft

Understanding the functions of an aircraft’s various control surfaces is one of the most important parts of being a pilot. Each surface affects the aircraft’s aerodynamic profile in different ways, and how they work and when to use them are the most important things a pilot can know. This includes the flaps mounted on the wings, which are vital for take-off and landing procedures.

A flap is placed on the trailing edge of an aircraft’s wing, between the fuselage and the ailerons mounted further out on the trailing edge. Large jetliners can have as many as three parts to their flaps, extended in sections during takeoff and landing. Flaps help to increase or decrease the camber, or surface area, of the aircraft wing. Camber includes how convex the upper part of the wing is, as well as the concavity of the lower half. When the aircraft is taking off, the flaps are deployed to help produce more lift. DUring landing, flaps are used to allow for a steep but controllable angle. Both of these functions help shorten how much runway is needed for takeoff and landing.

Small aircraft will use a plain flap, also referred to as “barn door flaps.” These flaps swing down from a hinge on the back of the wing, generating lift. While not as powerful as other flap designs, they are sufficient for small, general aviation aircraft. Split flaps extend from the lower part of the wing’s surface, and produce more lift than plain flaps. Partially invented by Orville Wright of the Wright brothers, they did not see much use after the 1930s. Most modern aircraft will use slotted flaps, which noticeably increase a wing’s camber by allowing a small opening between the flap and the rest of the wing. This allows the high pressure beneath the wing to rush above the wing, delaying airflow separation. Lastly, Fowler flaps are used on large jets to create massive amounts of lift and drag when needed. Fowler flaps extend in several stages, and depending on the aircraft, these flaps can run on racks or rails in a series controlled by the pilot. Flaperons also exist, in which a control surface serves as both an aileron, and a flap.

At ASAP Aviation Procurement, owned and operated by ASAP Semiconductor, we can help you find all the flap parts and systems for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at or call us at 1-714-705-4780.


October 12, 2022