In a bypass turbomachine, at least one air takeoff orifice is provided in the primary channel, said orifice leading to an air takeoff pipe housed inside an air inlet sleeve of the nacelle. The air takeoff pipe opens out in the vicinity of the pylon into two air diffusion pipes each secured to a respective maintenance cover, each air diffusion pipe opening out into an air injection pipe secured to a thrust reverser cover and itself opening out to the outside of the nacelle via the trailing edge thereof, each air injection pipe being suitable for uncoupling from the corresponding air diffusion pipe when the corresponding thrust reverser cover slides downstream.