Definition
A high-lift device mounted on the front edge of the wing that extends forward and downward to increase the wing's curvature and lift at low airspeeds, particularly during takeoff and landing.
Plain English
A movable panel on the front of the wing that drops down to help the airplane fly safely at slower speeds.
Context Anchor
Seen in airplane systems, wing design, takeoff and landing configuration, and slow-flight discussions.
Derivation
The 'leading edge' is the front edge of the wing — the edge that 'leads' into the oncoming air. A 'flap' is a hinged surface that can be moved to change the wing's shape. Together: a movable surface on the front of the wing.
Why Pilots Care
Improves low-speed handling and reduces stall speed, allowing safer operations near the ground.
Intuition Check
Do not picture a normal rear wing flap. A leading edge flap is on the front of the wing, and its main job is to help the wing keep lifting well when the airplane is slow or nose-high.
Example Sentence 1
As the airliner configured for landing, the leading edge flaps extended along with the trailing edge flaps to allow a slower, stable approach speed.
Example Sentence 2
Leading edge flaps allow the aircraft to maintain lift at higher angles of attack during takeoff.