Definition
Hinged surfaces on the trailing edge of the wing that the pilot can extend or retract to change the wing's lift and drag characteristics, primarily used to allow slower flight during takeoff, approach, and landing.
Plain English
Panels on the back edge of the wing that the pilot can lower to help the airplane fly slower without stalling, mainly for takeoff and landing.
Context Anchor
Seen in aircraft equipment descriptions, commercial pilot training requirements, preflight checks, and takeoff or landing procedures.
Derivation
"Movable" simply means able to be moved, which distinguishes these flaps from fixed surfaces on the wing. The point is that the pilot controls their position rather than them being built into a single shape.
Why Pilots Care
Proper use allows shorter takeoff rolls, steeper descent angles without excessive speed, and safer landings on shorter runways.
Grounding Statement
With the flaps retracted, the wing is cleaner for normal flight; with the flaps extended, the wing is shaped to help the airplane fly more slowly.
Intuition Check
“Movable” does not mean loose or free-swinging; it means the pilot can control the flap position. “Flaps” here does not mean any loose cover or panel; it means specific wing panels used to change how the wing flies.
Example Sentence 1
On final approach, the pilot lowered the movable flaps in stages to slow the airplane and steepen the descent.
Example Sentence 2
During the preflight walk-around the student checked that both movable flaps moved freely and symmetrically.