Definition
The maximum airspeeds at which the wing flaps may be extended or flown with flaps in a given setting, as published in the airplane's operating limitations. These speeds protect the flap structure and its attaching mechanism from aerodynamic loads that would exceed design strength. On the airspeed indicator, the upper limit of the white arc marks the maximum speed with flaps fully extended (V_FE).
Plain English
The fastest speeds at which it is safe to lower the flaps or fly with them already down. Go faster than this with flaps out and you can damage them.
Context Anchor
You will see flap limit airspeeds in the airplane's flight manual, on cockpit placards, and during approach and landing when selecting flap settings.
Derivation
“Flap” originally meant a loose or moving piece. That fits the airplane meaning: flaps are movable panels on the wing that change the wing’s shape for takeoff and landing. “Limit” points to the important part here: this is a maximum you must stay within, not a suggested speed.
Why Pilots Care
Exceeding these speeds risks structural damage to the flaps or wing, which can lead to loss of control or an emergency landing.
Intuition Check
Do not read “flap limit airspeeds” as target approach speeds. They are maximum allowed speeds for using each flap setting.
Example Sentence 1
On downwind, the pilot slowed below the flap limit airspeed before lowering the first notch of flaps.
Example Sentence 2
During the landing briefing the instructor emphasized checking flap limit airspeeds before extending full flaps on short final.