Lower attachment for trimmable horizontal stabiliser actuator

A lower attachment for a trimmable horizontal stabiliser actuator (THSA) for connecting the THSA to a flight control surface, the lower attachment comprising:

• a nut assembly for providing a load path through the THSA to the flight control surface when the THSA is connected to the flight control surface, comprising:
• a nut for location on a screw shaft of the THSA,
• a failsafe plate for coupling to the flight control surface, and
• a transfer plate for transferring load between the failsafe plate and the nut;
• wherein the nut assembly has a first unloaded configuration in which there is no contact between the nut and the transfer plate, and a second loaded configuration in which there is contact between a first pair of opposed surfaces of the nut and the transfer plate, and a clearance between a second pair of opposed surfaces of the nut and the transfer plate;
• and
• a locking assembly operable to prevent relative movement of the nut and the transfer plate in response to the nut assembly transitioning to the second configuration;
• the lower attachment also including a fuse arranged to move in response to transition of the nut assembly from the first configuration to the second configuration, and thereby indicate that transition.