An aircraft structure comprising; a rear spar, an upper cover which is attached to the rear spar and overhangs to its rear; a lower cover which is attached to the rear spar and overhangs to its rear, a hinge rib assembly comprising: a first hinge rib arm attached to a first one of the covers; and a second hinge rib arm connected to the first hinge rib arm and attached to a second one of the covers; and an aerodynamic control element pivotally mounted to the hinge rib assembly. The first and second hinge rib arms are separate parts. This provides the ability to disassemble the hinge rib in-situ for repair or maintenance purposes; the ability to install or remove the hinge rib without having to move it inboard along the structure; reduced material wastage during manufacture; and the ability to install one or more elongate lines which extend in a span-wise direction along the aircraft structure.