Propulsion system for an aircraft comprising a bypass turbine engine and a pylon, in which the bypass turbine engine comprises an engine with a fan, two internal cowls surrounding the engine, a fan case and two outer cowls surrounding the internal cowls to define a secondary flow path and positioned to the rear of the fan case, in which the outer cowls are able to move in translation with respect to the engine between a forward position in which the outer cowls are against the rear of the fan case and a retracted position in which the two outer cowls are distant from the fan case to open up a window between the secondary flow path and the outside, in which the bypass turbine engine further comprises, for each outer cowl, at least one door mounted with the ability to rotate on the outer cowl between a non-obstructing position in which the door is not across the secondary flow path and a deployed position in which the door is across the secondary flow path in order to divert the flow of air towards the window, in which the bypass turbine engine further comprises cascades of vanes which are fixed to the outer cowl via hooping means which may alternately adopt a hooping position in which they lock the cascades of vanes to the outer cowl and a disengaged position in which they release the cascades of vanes from the outer cowl, in which each outer cowl is mounted with the ability to slide parallel to a direction of translation on the corresponding internal cowl and in which each outer cowl is mounted with the ability to slide parallel to the direction of translation on the pylon, the turbine engine comprising locking means which can alternately adopt a locked position in which they lock the internal cowls of the engine and an unlocked position in which they release the internal cowls of the engine, each outer cowl being mounted with the ability to slide on the corresponding internal cowl via a top guideway connection and a bottom guideway connection and on the pylon via an upper guideway connection, in which the upper guideway connection comprises, on the one hand, a beam having a slot and, on the other hand, at least one slider secured to the outer cowl which slides in the slot and at least one slider secured to the cascades of vanes which slides in the slot, in which the beam is fixed to the pylon via a pivot connection about an axis of rotation parallel to the direction of translation allowing the outer cowl to move between a closed position in which the outer cowl is closed up around the engine and an open position in which the outer cowl is distant from the engine. in which the outer cowls are able to move in translation with respect to the engine between a forward position in which the outer cowls are against the rear of the fan case and a retracted position in which the two outer cowls are distant from the fan case to open up a window between the secondary flow path and the outside, in which the bypass turbine engine further comprises, for each outer cowl, at least one door mounted with the ability to rotate on the outer cowl between a non-obstructing position in which the door is not across the secondary flow path and a deployed position in which the door is across the secondary flow path in order to divert the flow of air towards the window, in which the bypass turbine engine further comprises cascades of vanes which are fixed to the outer cowl via hooping means which may alternately adopt a hooping position in which they lock the cascades of vanes to the outer cowl and a disengaged position in which they release the cascades of vanes from the outer cowl, in which each outer cowl is mounted with the ability to slide parallel to a direction of translation on the corresponding internal cowl and in which each outer cowl is mounted with the ability to slide parallel to the direction of translation on the pylon, the turbine engine comprising locking means which can alternately adopt a locked position in which they lock the internal cowls of the engine and an unlocked position in which they release the internal cowls of the engine, each outer cowl being mounted with the ability to slide on the corresponding internal cowl via a top guideway connection and a bottom guideway connection and on the pylon via an upper guideway connection, in which the upper guideway connection comprises, on the one hand, a beam having a slot and, on the other hand, at least one slider secured to the outer cowl which slides in the slot and at least one slider secured to the cascades of vanes which slides in the slot, in which the beam is fixed to the pylon via a pivot connection about an axis of rotation parallel to the direction of translation allowing the outer cowl to move between a closed position in which the outer cowl is closed up around the engine and an open position in which the outer cowl is distant from the engine.