Abstract: An aircraft assembly having a first region, a second region spaced from the first region by a flexible region, and a deflection sensor. The first region has greater positional stability than the second region such that the second region deflects further from its default position than the first region during in-use loads. The deflection sensor includes a first gyroscope at the first region to generate a first signal representing rotation of the first region about one or more orthogonal axes, and a second gyroscope at the second region to generate a second signal representing rotation of the second region about the one or more axes. The second gyroscope is synchronised in time with the first. A controller subtracts one of the first and second signals from the other to obtain a differential signal representing deflection of the second region relative to the first due to flexing of the flexible region.

Abstract: An aircraft assembly having a first region, a second region spaced from the first region by a flexible region, and a deflection sensor. The first region has greater positional stability than the second region such that the second region deflects further from its default position than the first region during in-use loads. The deflection sensor includes a first gyroscope at the first region to generate a first signal representing rotation of the first region about one or more orthogonal axes, and a second gyroscope at the second region to generate a second signal representing rotation of the second region about the one or more axes. The second gyroscope is synchronised in time with the first. A controller subtracts one of the first and second signals from the other to obtain a differential signal representing deflection of the second region relative to the first due to flexing of the flexible region.

Abstract: Method and system of determining ground-to-tire friction coefficient for an aircraft landing event. The method uses an aircraft computational model to repeatedly model the landing event, varying one or more initial conditions of the aircraft model until a best match between a modelled value and a provided value of aircraft vertical acceleration is determined. The method uses initial conditions associated with the best match of modelled and provided vertical acceleration values and a strain value from a sensor on the aircraft landing gear, with the ground-to-tire friction coefficient is a variable. The method models the landing gear to generate a modelled strain value and compares this with the measured strain value, and repeats the landing gear modelling step with a different value for the ground-to-tire friction coefficient until a best match between the modelled strain value and the measured strain value is determined and outputting the respective friction coefficient value.

Abstract: Method and system of determining ground-to-tyre friction coefficient for an aircraft landing event. The method uses an aircraft computational model to repeatedly model the landing event, varying one or more initial conditions of the aircraft model until a best match between a modelled value and a provided value of aircraft vertical acceleration is determined. The method uses initial conditions associated with the best match of modelled and provided vertical acceleration values and a strain value from a sensor on the aircraft landing gear, with the ground-to-tyre friction coefficient is a variable. The method models the landing gear to generate a modelled strain value and compares this with the measured strain value, and repeats the landing gear modelling step with a different value for the ground-to-tyre friction coefficient until a best match between the modelled strain value and the measured strain value is determined and outputting the respective friction coefficient value.