A holder for a wireless relay device is disclosed including a rigid hollow arm member to be received in a groove in a torque tube spline of an aircraft wheel brake; and a support member to support the wireless relay device, the support member mechanically coupled to the rigid hollow arm member towards a first end of the rigid hollow arm member, wherein: the rigid hollow arm member provides a conduit for a communications cable to couple to the wireless relay device. Also disclosed is an aircraft wheel brake comprising the holder and an aircraft comprising the aircraft wheel brake.

A brake disc for an aircraft wheel brake including: a temperature sensing device comprising a surface acoustic wave (SAW) sensor element and a sensor antenna, wherein the temperature sensing device is attached to the brake disc by means of a ceramic adhesive and one or more ceramic bolts. A method of attaching a temperature sensing device to a brake disc of an aircraft wheel brake.

A brake disc for an aircraft wheel brake including: a temperature sensing device comprising a surface acoustic wave (SAW) sensor element and a sensor antenna, wherein the temperature sensing device is attached to the brake disc by means of a ceramic adhesive and one or more ceramic bolts. A method of attaching a temperature sensing device to a brake disc of an aircraft wheel brake.

A hydraulic system 300 for an aircraft including a backup hydraulic pressure source 216 to provide hydraulic pressure to a brake 222 in the event of a failure condition of a primary hydraulic brake pressure source. The hydraulic system 300 also includes a landing gear backup system to provide hydraulic pressure to enable extension and/or retraction of landing gear 100. The backup hydraulic pressure source 216 is arranged to provide hydraulic pressure to the landing gear backup system in the event of a failure condition of a primary landing gear hydraulic pressure source.

A hydraulic system 300 for an aircraft including a backup hydraulic pressure source 216 to provide hydraulic pressure to a brake 222 in the event of a failure condition of a primary hydraulic brake pressure source. The hydraulic system 300 also includes a landing gear backup system to provide hydraulic pressure to enable extension and/or retraction of landing gear 100. The backup hydraulic pressure source 216 is arranged to provide hydraulic pressure to the landing gear backup system in the event of a failure condition of a primary landing gear hydraulic pressure source.

A brake cooling period prediction system for predicting a brake cooling period following a braking event, and including a sensor apparatus in communication with a prediction apparatus. The sensor apparatus has a torque sensor for measuring the torque reacted by a brake during a braking event; a wear sensor for measuring a wear state of the brake; and an environmental sensor for measuring at least one ambient condition of the environment of the brake. The prediction apparatus includes a memory storing information relating to the thermal behavior of the brake; and a controller configured to receive a torque measurement, a wear measurement and an ambient condition measurement from the sensor apparatus; and predict a cooling period based on the received torque, wear and ambient condition measurements, and the information relating to the thermal behavior of the brake.

A piston housing may comprise: a main annular ring defining a main bore; a torque takeout annular ring defining a torque takeout bore; a torque takeout arm extending from the main annular ring to the torque takeout annular ring and defining an aperture therethrough; and a structural rib disposed within the aperture and extending from the main annular ring to the torque takeout annular ring.

A piston housing may comprise: a main annular ring defining a main bore; a torque takeout annular ring defining a torque takeout bore; a torque takeout arm extending from the main annular ring to the torque takeout annular ring and defining an aperture therethrough; and a structural rib disposed within the aperture and extending from the main annular ring to the torque takeout annular ring.

A brake control system of the present disclosure calibrates a servo valve and calculates a calibrated transfer function associated with the servo valve for precise braking in open-loop mode. The calibration steps may include determining i) whether an aircraft is on a ground surface, ii) whether the aircraft is not moving relative to the ground surface, and iii) whether braking is applied to a brake system of the aircraft. The brake control unit may calibrate the servo valve in response to the brake control unit determining that i) the aircraft is on the ground surface, ii) the aircraft is not moving relative to the ground surface, and iii) the braking is not applied to the brake system of the aircraft. The calibration process includes sending two or more test currents to the servo valve, and determining braking pressures associated with those test currents to calculate the transfer function.

Various embodiments of aircraft brake assembly structures are provided for achieving noise reduction during braking activity. In certain embodiments of the invention, the actual application of force to the pressure plate is regulated such that a different number of actuator pistons are used during low-energy stops than during high-energy stops. In other embodiments of the invention, the pressure plate or endplate is augmented as to surface area in some instances and as to a taper angle in others, again to achieve a desired increase in effective pressure application during low-energy stops. In other embodiments of the invention, the stator and/or rotor disks are characterized by slots to break up the propagation of noise waves.