A turbofan having a nacelle including a slider mobile in translation between advanced and retracted positions to open a window between a duct and the exterior, a plurality of blades, each being mobile in rotation on the slider between stowed and deployed positions, and a maneuvering system that moves each blade and includes, for each blade, a shaft mobile in rotation on the slider and on which the blade is fixed, an arm having a first end fixed to the shaft and a second end, an arc which is coaxial with the longitudinal axis and is rotatably mounted on the slider, about the longitudinal axis, a lever mounted in articulated fashion between the arc and the second end of the arm, and an actuation system which rotates the arc in one direction and in the other.