Abstract: A method of testing a system model is disclosed. The system model includes a system parameter and three or more equipment models, each equipment model includes an equipment parameter which models a parameter of a respective equipment. The method includes (a) making a series of changes of the equipment parameter of one of the equipment models so that the equipment parameter of the one of the equipment models adopts a series of test values of the equipment parameter; (b) operating the system model to determine a series of test values of the system parameter, each test value of the system parameter is determined in accordance with a respective one of the test values of the equipment parameter; (c) determining a weight of the selected one of the equipment models, the weight of the one of the equipment models indicates a sensitivity of the system parameter to the series of changes in the equipment parameter of the one of the equipment models; and (d) outputting the weight of the one of the equipment models.

Abstract: An aircraft control system (100) including an aircraft control module (110) and a test module (120). The aircraft control module includes a memory storing a machine learning model (130) adapted, based on received live aircraft operating inputs (102a-102f), to generate live aircraft control outputs (104a-104b). The test module (120) includes a memory storing input data representing test aircraft operating inputs (102a?-102f?) and respective output data representing expected aircraft control outputs (114a, 114b) that are expected to be generated by the aircraft control module in response to an input of the respective test aircraft operating inputs (102a?-102f?). The test module (120) is adapted to write test aircraft operating inputs (102a?-102f?) to the aircraft control module, read test aircraft control outputs (104a?-104b?) of the aircraft control module (110), and remove the authority of the aircraft control module (110) to perform aircraft control.

Abstract: A method of testing a system model is disclosed. The system model includes a system parameter and three or more equipment models, each equipment model includes an equipment parameter which models a parameter of a respective equipment. The method includes (a) making a series of changes of the equipment parameter of one of the equipment models so that the equipment parameter of the one of the equipment models adopts a series of test values of the equipment parameter; (b) operating the system model to determine a series of test values of the system parameter, each test value of the system parameter is determined in accordance with a respective one of the test values of the equipment parameter; (c) determining a weight of the selected one of the equipment models, the weight of the one of the equipment models indicates a sensitivity of the system parameter to the series of changes in the equipment parameter of the one of the equipment models; and (d) outputting the weight of the one of the equipment models.

Abstract: An apparatus for reducing brake wear having a brake de-selection function for selectively disabling at least one brake on a vehicle; and a controller. The controller is configured to receive torque information which relates to torque reacted by a brake on the vehicle during a braking event and wheel speed information which relates to a speed of a wheel associated with the brake during the braking event; calculate an energy input into the brake during the braking event, based on the received torque information and the received wheel speed information; determine whether the calculated energy input meets at least one predefined energy input criterion; and activate the brake de-selection function if the calculated energy input meets the at least one predefined energy input criterion.

Abstract: A control system for controlling a landing gear drive system for driving rotation of an aircraft wheel is disclosed having a control panel with a controller having a forward motion setting and a zero speed setting, a control unit for receiving a control input from the controller, and for providing a torque command to be applied to the wheel, and a speed sensor for sensing an aircraft taxi speed and for providing an indication of the aircraft taxi speed to the control unit. When the controller is moved from the forward motion setting to the zero speed setting, the control unit provides a torque command to the drive system to provide zero forwards driving torque to the wheel, and a braking command to apply a braking torque to the wheel.

Abstract: An apparatus for reducing brake wear having a brake de-selection function for selectively disabling at least one brake on a vehicle; and a controller. The controller is configured to receive torque information which relates to torque reacted by a brake on the vehicle during a braking event and wheel speed information which relates to a speed of a wheel associated with the brake during the braking event; calculate an energy input into the brake during the braking event, based on the received torque information and the received wheel speed information; determine whether the calculated energy input meets at least one predefined energy input criterion; and activate the brake de-selection function if the calculated energy input meets the at least one predefined energy input criterion.

Abstract: An apparatus for reducing brake wear having a brake de-selection function for selectively disabling at least one brake on a vehicle; and a controller. The controller is configured to receive torque information which relates to torque reacted by a brake on the vehicle during a braking event and wheel speed information which relates to a speed of a wheel associated with the brake during the braking event; calculate an energy input into the brake during the braking event, based on the received torque information and the received wheel speed information; determine whether the calculated energy input meets at least one predefined energy input criterion; and activate the brake de-selection function if the calculated energy input meets the at least one predefined energy input criterion.

Abstract: A braking control system for an aircraft having braking wheels, the braking control system being configured to receive input of signals from sensors representative of a plurality of measured aircraft parameters, and to output a plurality of brake commands to brakes associated with the braking wheels, wherein the braking control system includes a health monitoring system for determining the operability and/or reliability of the sensor signals and/or of the braking wheels, and a task manager for automatically self-reconfiguring the braking control system so as to change the manner in which the braking control system utilises the input signals in the event that the health monitoring system judges a failure of one or more of the braking wheels or sensor signals. Also a method for operating an aircraft having a plurality of braking wheels.

Abstract: A method of controlling the motion of a turning aircraft during taxiing on the ground, the aircraft having a steerable landing gear, for example a nose landing gear, operating in a free-to-caster mode, includes (a) ascertaining the rotational position (?) of the steerable landing gear relative to the longitudinal axis (L) of the aircraft (b) receiving a control instruction that would, if effected, continue turning of the aircraft in the same direction away from the longitudinal axis, and (c) modifying the control instruction so that the angle between the rotational position of the steerable landing gear and the longitudinal axis will be lower than the angle that would otherwise be observed had the control instruction been effected and not so modified. The risk of damage to the steerable landing gear through over-steering may thus be reduced.

Abstract: An apparatus for reducing brake wear having a brake de-selection function for selectively disabling at least one brake on a vehicle; and a controller. The controller is configured to receive torque information which relates to torque reacted by a brake on the vehicle during a braking event and wheel speed information which relates to a speed of a wheel associated with the brake during the braking event; calculate an energy input into the brake during the braking event, based on the received torque information and the received wheel speed information; determine whether the calculated energy input meets at least one predefined energy input criterion; and activate the brake de-selection function if the calculated energy input meets the at least one predefined energy input criterion.

Abstract: A data processing unit for monitoring the performance of at least one undercarriage which is used for braking and/or steering an aircraft, wherein the data processing unit is configured to: receive data representative of operating characteristics of the undercarriage(s) and use that data to calculate a maximum achievable braking force and/or yaw moment to be generated by the undercarriage(s). Also a method for monitoring the performance of at least one aircraft undercarriage which is used for braking and/or steering an aircraft, the method including: receiving data representative of operating characteristics of the undercarriage(s); and using that data to calculate a maximum achievable braking force and/or yaw moment to be generated by the undercarriage(s).

Abstract: A controller for an aircraft steering system, the controller being configured to receive a steering input representative of a desired direction of travel of a steerable nose landing gear, and to receive one or more force-based inputs representative of lateral forces acting upon the nose landing gear, wherein the controller is adapted to automatically adjust the steering input based upon the force-based input(s) so as to output an adjusted steering command for a steering actuator of the nose landing gear.

Abstract: An aircraft landing gear longitudinal force control system for an aircraft having landing gears with braking and/or driving wheel(s). The system includes an error-based force controller having feedback for minimising any error between the demanded force and the actual force achieved by the force control system. The feedback may be derived from force sensors on the landing gear for direct measurement of the landing gear longitudinal force. The force control system may include an aircraft level landing gear total force controller and/or a landing gear level force controller for each actuated landing gear.

Abstract: A method of braking left and right landing gear wheels on respective left and right sides of an aircraft. A desired left braking parameter (L) is received for the left wheel and a desired right braking parameter (R) is received for the right wheel. The left wheel is braked with a reduced left braking parameter (L?) which is less than the desired left braking parameter (L), and the right wheel is braked with a reduced right braking parameter (R?) which is less than the desired right braking parameter (R). A difference between the braking parameters is maintained so that L??R?=L?R.

Abstract: A slip-reduction control unit for an aircraft having a steerable landing gear. The control unit receives steering input signals from which a target steering command output may be ascertained and additional input signals (a) the motion of the aircraft, (b) a steering angle, or (c) a parameter relating to the slip sustained by the steerable landing gear. The slip-reduction control unit determines, based on the additional input signals, reduces the rate of change of steering angle that would otherwise be commanded. The reduction in the rate of change may reduce vibration on the aircraft that might be caused by a greater rate of change in the steering angle.

Abstract: A device for lateral control of an aircraft includes a calculating unit for automatically applying, if conditions for turning of the aircraft are met, a symmetrical braking value at a brake assembly. Subsequently, in the course of the turn, the device automatically distributes this symmetrical braking value in differential braking between a braking device of the left main landing gear and a braking device of the right main landing gear of the aircraft. Distribution of the symmetrical breaking is performed as a function of current directional command orders in such a way as to maintain a constant overall braking level for, at least for directional command orders below a predetermined threshold.

Abstract: A controller for an aircraft steering system, the controller being configured to receive a steering input representative of a desired direction of travel of a steerable nose landing gear, and to receive one or more force-based inputs representative of lateral forces acting upon the nose landing gear, wherein the controller is adapted to automatically adjust the steering input based upon the force-based input(s) so as to output an adjusted steering command for a steering actuator of the nose landing gear.

Abstract: A braking control system for an aircraft having braking wheels, the braking control system being configured to receive input of signals from sensors representative of a plurality of measured aircraft parameters, and to output a plurality of brake commands to brakes associated with the braking wheels, wherein the braking control system includes a health monitoring system for determining the operability and/or reliability of the sensor signals and/or of the braking wheels, and a task manager for automatically self-reconfiguring the braking control system so as to change the manner in which the braking control system utilises the input signals in the event that the health monitoring system judges a failure of one or more of the braking wheels or sensor signals. Also a method for operating an aircraft having a plurality of braking wheels.

Abstract: A data processing unit for monitoring the performance of at least one undercarriage which is used for braking and/or steering an aircraft, wherein the data processing unit is configured to: receive data representative of operating characteristics of the undercarriage(s) and use that data to calculate a maximum achievable braking force and/or yaw moment to be generated by the undercarriage(s). Also a method for monitoring the performance of at least one aircraft undercarriage which is used for braking and/or steering an aircraft, the method including: receiving data representative of operating characteristics of the undercarriage(s); and using that data to calculate a maximum achievable braking force and/or yaw moment to be generated by the undercarriage(s).

Abstract: An aircraft landing gear longitudinal force control system for an aircraft having landing gears with braking and/or driving wheel(s). The system includes an error-based force controller having feedback for minimising any error between the demanded force and the actual force achieved by the force control system. The feedback may be derived from force sensors on the landing gear for direct measurement of the landing gear longitudinal force. The force control system may include an aircraft level landing gear total force controller and/or a landing gear level force controller for each actuated landing gear.