The load on an aircraft component is measured. In one embodiment, the system is a contactless, all-weather displacement measuring system including a processing unit and a plurality of pairs of controllable microwave emitters and microwave detectors. When the aircraft component is subjected to a load, relative movement of the emitter and detector is caused. The detector generates signals which convey information concerning the relative positions of the emitter and the detector of the pair, the signals being received and processed by a signal processor of the processing unit. The processing unit may, for example with the use of triangulation techniques, provide an output signal representative of the load sustained by the aircraft component. The system may be used to control braking in dependence on the output signal so as to maximise braking efficiency without overloading the landing gear leg.