A structural mechanism for an aircraft includes a support, a hinged surface, and a hinge assembly joining the hinged surface to the support. An actuation system includes an actuator shaft engaged to the hinges and lying coincident with a hinged-surface hinge axis and extending through the aligned center passagways of the hinges of the hinge assembly. A lock is selectively operable to lock the hinged surface to the support when the actuator shaft engages the lock. An actuator structure is controllably operable to move the actuator shaft longitudinally along the hinge-surface hinge axis between a first shaft axial position wherein the actuator shaft engages the lock and the hinges, and a second shaft axial position wherein the actuator shaft does not engage the lock but does engage the hinges, and is controllably operable to rotate the actuator shaft about the hinged-surface hinge axis.