Where is the Leading Edge Extension (LEX) located and what does it provide?

• A. It provides added lift at high angles of attack and is mounted on either side of the forward fuselage as an extension of the wing leading edge.
• B. It deflects to produce roll motion in flight.
• C. It is a stabilizer that provides pitch control.
• D. It is a trailing edge flap used for lift during takeoff.

Answer: (A)

Leading Edge Extensions are fixed surfaces on both sides of the forward fuselage that extend the wing’s leading edge at the root. Their job is to generate a strong leading-edge vortex when the aircraft is at high angles of attack. This vortex energizes the flow over the wing, delaying separation, increasing lift, and improving stability and controllability during aggressive, high-AoA maneuvers. They’re not movable devices for rolling, aren’t stabilizers for pitch, and aren’t trailing-edge flaps.