An assembly for an aircraft propulsion system, comprising: a nacelle comprising an outer structure and an inner structure, a bypass flowpath formed by and radially between the outer structure and the inner structure; the inner structure including a support structure, a first core cowl and a second core cowl; the support structure including a plurality of first hinges, a plurality of second hinges, a plurality of longitudinal rails and a plurality of crossover rails spaced longitudinally along and connected to the plurality of longitudinal rails, each of the plurality of first hinges connected to a respective one of the plurality of crossover rails at a first distal end of the respective one of the plurality of crossover rails, each of the plurality of second hinges connected to a respective one of the plurality of crossover rails at a second distal end of the respective one of the plurality of crossover rails; the first core cowl pivotally mounted to the support structure by the plurality of first hinges; and the second core cowl pivotally mounted to the support structure by the plurality of second hinges, characterized in that: the support structure further includes a first mounting bracket, a second mounting bracket, an additional first hinge and an additional second hinge; the first mounting bracket is mounted to and projects laterally out from a first of the plurality of longitudinal rails in a first lateral direction, and the additional first hinge pivotally mounts the first core cowl to the first mounting bracket; and the second mounting bracket is mounted to and projects laterally out from a second of the plurality of longitudinal rails in a second lateral direction that is opposite the first lateral direction, and the additional second hinge pivotally mounts the second core cowl to the second mounting bracket. a nacelle comprising an outer structure and an inner structure, a bypass flowpath formed by and radially between the outer structure and the inner structure; the inner structure including a support structure, a first core cowl and a second core cowl; the support structure including a plurality of first hinges, a plurality of second hinges, a plurality of longitudinal rails and a plurality of crossover rails spaced longitudinally along and connected to the plurality of longitudinal rails, each of the plurality of first hinges connected to a respective one of the plurality of crossover rails at a first distal end of the respective one of the plurality of crossover rails, each of the plurality of second hinges connected to a respective one of the plurality of crossover rails at a second distal end of the respective one of the plurality of crossover rails; the first core cowl pivotally mounted to the support structure by the plurality of first hinges; and the second core cowl pivotally mounted to the support structure by the plurality of second hinges, the support structure further includes a first mounting bracket, a second mounting bracket, an additional first hinge and an additional second hinge; the first mounting bracket is mounted to and projects laterally out from a first of the plurality of longitudinal rails in a first lateral direction, and the additional first hinge pivotally mounts the first core cowl to the first mounting bracket; and the second mounting bracket is mounted to and projects laterally out from a second of the plurality of longitudinal rails in a second lateral direction that is opposite the first lateral direction, and the additional second hinge pivotally mounts the second core cowl to the second mounting bracket.