How the Wing Flaps Help an Airplane Ascend and Descend

John Moss Wathen IV holds an aerospace engineering degree and has a passion for flight. John Wathen IV has extensive knowledge of wing aerodynamics.

On an airplane, the flaps are on the outside edge of the wings, between the ailerons (small hinged sections near the end of the wing) and the fuselage. The flaps may have three parts that work together to change the wing shape and divert air around them. When the flaps are up, camber (wing surface area) is increased, and lift at takeoff becomes easier.

As the airplane settles into cruising altitude, the pilot retracts the wing flaps completely so that no drag is generated. The flaps are extended to create a “broken wing” or drag when the pilot wants to slow down, such as when approaching landing.

The flap setting is generally between 25 and 40 degrees, but this can vary depending on the steepness of the ascent or descent. For example, if a pilot is in danger of overrunning the landing area, he can increase the flap angles while power and pitch are decreased. The reverse is called for when the landing area appears sooner than expected.