Mobile leading edge flap for a main wing of the aerofoils of an aircraft and main wing provided with such a flap

Leading edge mobile flap (16) for a main wing (4) of the wing system of an aircraft (1), said flap including an aerodynamic skin (18) that has a bird impact-sensitive frontal area (24), and a rear skin (28) extending between and intergral with a trailing edge (22a) of an upper surface portion (22) of the aerodynamic skin (18) and with a trailing edge (20a) of a lower surface portion (20) of this skin (18), said flap also comprising a plurality of ribs (32, 34, 40) spaced out along a leading edge longitudinal direction (X′), characterised in that the flap additionally includes, between two directly consecutive ribs, a single rigid bird trajectory-deflecting wall (42) anchored to the aerodynamic skin (18) and to the rear skin (28), this wall (42) being capable of deflecting the trajectory of a bird subsequent to it impacting against said impact area (24), and in that in a cross-section taken along any plane orthogonal to the leading edge longitudinal direction (X′), said rigid deflecting wall (42) forms with a geometric chord (26) of the flap an angle (α1) with a value of less than 45°.