NSN 1560-01-090-0539

A movable control surface attached to the leading edge of a wing or other airfoil which, when extended, creates a slot to allow high-energy air to be introduced into the boundary layer over the top of the airfoil. it prevents stalls at high angles of attack and improves lateral control at lower than normal airspeeds. it is closed during normal flight and forms a profile of the airfoil. excludes leading edge devices for creating lift that are not slotted to duct air over the top of a wing or other airfoil. excludes flap, wing landing.