Abstract: The nacelle (3) is characterized in that it includes at least one cable (6) having a top end that leaves the nacelle upwardly and a bottom end that leaves the nacelle downwardly, and a mechanism (11) enabling the nacelle to move up and down the cable when the top end of the cable is hooked to a hook unit (4). A mechanism enables the top portion of the cable to be subjected to a tension greater than the weight of the nacelle while the bottom portion (7) of the cable is fixed to an anchor point, said tensioning mechanism serving to vary the distance between the nacelle (3) and said hook unit at the top end of the cable. Further, mechanism (12, 14) acts on command, on said tensioning mechanism in such a manner as to prevent the distance between the nacelle (3) and the hook unit (4) at the top end of the cable from shortening while not preventing it from lengthening.