The primary function of leading-edge flaps in landing configuration during the flare before touchdown is to?

The primary function of leading-edge flaps during the landing configuration, particularly in the flare before touchdown, is to prevent flow separation over the wing. When an aircraft approaches the runway in the landing phase, it operates at a high angle of attack. Leading-edge flaps increase the camber of the wing, which enhances the aerodynamic characteristics at this critical angle of attack. This design modification helps maintain smoother airflow over the wing’s surface.

When airflow separates from the airfoil, it can lead to a stall, significantly impacting the aircraft's control and performance. By extending the leading-edge flaps, the aircraft can maintain lift at lower speeds and higher angles of attack, reducing the risk of flow separation. This ensures a more controlled descent and stable approach, thus enhancing overall safety during landing.

While other options also relate to various aerodynamic effects during flight, the unique role of leading-edge flaps in maintaining attached airflow makes this the most appropriate choice for their function in the landing phase.