Patent ID: 7578199

Claim:
An aircraft including an apparatus for measuring a load on an aircraft component, the apparatus including a processing unit, a watertight housing, a controllable source of light, and a detector able to detect light emitted from said source, wherein the source and the detector are situated in the watertight housing and are thereby situated in a region that is protected from the environment to the exterior of the aircraft, the apparatus is arranged so that, when the aircraft component is subjected to a load of the type to be measured, relative movement of the detector and the position of the light from the source in the region of the detector is caused, the detector in use generates in response to light received from the source a signal that is received by the processing unit, the signal being dependent on the relative positions of the detector and the light from the source in the region of the detector, and the processing unit is arranged to provide an output signal dependent on the load sustained by the aircraft component.