An aircraft engine nacelle is provided that includes a fixed front frame, a thrust reverser cowling mounted to slide with respect to the front frame between a direct-jet position and a reversed-jet position, a variable-geometry nozzle positioned in a downstream continuation of the reverser cowling, thrust-reversal jacks interposed between the front frame and the thrust-reverser cowling, adaptive nozzle jacks interposed between said thrust reverser cowling and the variable-geometry nozzle, drive shafts mounted on the front frame, transmission shafts extending along the thrust reverser cowling as far as the variable-geometry nozzle jacks, and mechanical means for coupling said transmission shafts to said drive shafts, and means for locking rotation of said transmission shafts before decoupling of the transmission shafts from their respective drive shafts, and when the decoupling is completed.