An aircraft includes a first landing gear assembly, a second landing gear assembly, a braking circuit, a brake control circuit, and a braking capability circuit. The landing gear assemblies each include a first braking wheel and a second braking wheel. The braking circuit may apply brakes independently to each of the braking wheels. The brake control circuit actuates braking of the first braking wheels in response to initial receipt of a braking command in a first braking phase and restrict braking at the second braking wheels during the first braking phase until the first braking wheels reach an anti-skid limit at an end of the first braking phase. The braking capability circuit determines a braking capability of the aircraft based on an amount of braking applied to reach the anti-skid limit at the first braking wheels.

An aircraft includes a first landing gear assembly, a second landing gear assembly, a braking circuit, a brake control circuit, and a braking capability circuit. The landing gear assemblies each include a first braking wheel and a second braking wheel. The braking circuit may apply brakes independently to each of the braking wheels. The brake control circuit actuates braking of the first braking wheels in response to initial receipt of a braking command in a first braking phase and restrict braking at the second braking wheels during the first braking phase until the first braking wheels reach an anti-skid limit at an end of the first braking phase. The braking capability circuit determines a braking capability of the aircraft based on an amount of braking applied to reach the anti-skid limit at the first braking wheels.

A method of controlling and optimizing braking and directional control of a vehicle operated on a contaminated, compliant, or non-compliant surface. The method includes steps of: collecting data from a plurality of sensors, the data being indicative of a condition of the contaminated, compliant, or non-compliant surface; sending the data to a neural controller having an algorithm configured to process the data. The algorithm includes: determining optimum braking and directional control instructions for the vehicle, generating warnings and alerts based on the calculated optimum braking and directional control instructions, and sending the optimum braking and directional control instructions to a braking and steering system of the vehicle and the warnings and alerts to an alert and warning system of the vehicle. The method further includes adjusting the steering and directional control of the braking and steering system in accordance with the optimum braking and directional control instructions provided by the neural controller.

A method is provided for diagnosing a failure on an aircraft that includes aircraft systems configured to report faults to an onboard reasoner. The method includes receiving a fault report at an onboard computer of the aircraft from an aircraft system of the aircraft systems, the fault report indicating failed tests reported by the aircraft system. The onboard reasoner accesses an onboard diagnostic causal model represented by a graph describing known causal relationships between possible failed tests reported by the respective ones of the aircraft systems, and possible failure modes of the respective ones of the aircraft systems. The onboard reasoner diagnoses a failure mode of the aircraft system or another of the aircraft systems, from the failed tests, and using a graph-theoretic algorithm and the onboard diagnostic causal model. A maintenance action is determined for the failure mode, and a maintenance message is generated including the maintenance action.

There is provided a pivot turn load alleviation (PTLA) brake system for alleviating structural loads on a pivoting main landing gear of an aircraft in a pivot turn maneuver. The PTLA brake system includes a brake control system operatively coupled to at least two main landing gear, each having two or more wheels. The PTLA brake system further includes a PTLA brake inhibit subsystem coupled to the brake control system. The subsystem inhibits braking of one or more of the two or more wheels of the pivoting main landing gear, in the pivot turn maneuver, so that at least one wheel of the two or more wheels is in an unbraked state, and a remaining number of the two or more wheels are in a braked state. The PTLA brake system alleviates structural loads, and reduces wear on the at least one wheel that is in the unbraked state.

Methods and apparatus for controlling landing gear retract braking are described. A controller determines wheel speed data corresponding to a speed of a wheel of a landing gear. The controller determines wheel deceleration data corresponding to a rate of change of the wheel speed data. The controller generates a first control signal in response to the wheel deceleration data being greater than a wheel deceleration threshold. The first control signal initiates a wheel deceleration regulation process, the wheel deceleration regulation process to cycle an antiskid valve between a first valve position to release brake pressure from the wheel and a second valve position to cease releasing the brake pressure from the wheel. The controller generates a second control signal in response to the wheel speed data being less than a wheel speed threshold. The second control signal terminates the wheel deceleration regulation process.

Methods and apparatus for controlling landing gear retract braking are described. A controller determines wheel speed data corresponding to a speed of a wheel of a landing gear. The controller determines wheel deceleration data corresponding to a rate of change of the wheel speed data. The controller generates a first control signal in response to the wheel deceleration data being greater than a wheel deceleration threshold. The first control signal initiates a wheel deceleration regulation process, the wheel deceleration regulation process to cycle an antiskid valve between a first valve position to release brake pressure from the wheel and a second valve position to cease releasing the brake pressure from the wheel. The controller generates a second control signal in response to the wheel speed data being less than a wheel speed threshold. The second control signal terminates the wheel deceleration regulation process.

An antiskid controller for controlling braking operation of a wheel of a vehicle based on an output signal provided by a wheel speed sensor coupled to the wheel may comprise a delay toggle, a switch logic for switching between an initial rate and a running rate, and a linear control used for calculating an antiskid correction signal, wherein the linear control receives one of the initial rate and the running rate, depending on a state of the switch logic. The linear control receives the initial rate upon initialization of the antiskid controller. The linear control receives the running rate after a predetermined duration or after the linear control has converged on a desired solution.

Brake control systems are disclosed herein. A brake control system comprises a first set of analog-to-digital converters in electrical communication with a first set of brake input mechanism sensors and a second set of analog-to-digital converters in electrical communication with a second set of brake input mechanism sensors. The first and second sets of analog-to-digital converters comprise one or more of different hardware and different software for differentially manipulating sensor outputs received from the brake input mechanism sensors.

A brake system is disclosed. The brake system includes a brake stack having a stack closure pressure, a force member positioned within a cylinder, a valve configured to control fluid pressure of the brake system, and one or more pressure transducers that generate a proportional electrical signal representative of the fluid pressure within the cylinder. The brake system also includes one or more processors in electronic communication with the valve, the one or more pressure transducers, and a memory coupled to the one or more processors. The memory stores data comprising a database and program code that, when executed by the one or more processors, causes the brake system to determine the stack closure pressure of the brake stack.