The present disclosure provides a brake system including (a) a brake stack, (b) a force member moveable between a retracted position and an extended position in response to a brake command, wherein the force member contacts the brake stack in the extended position, and wherein the brake system includes a running clearance defined by a distance between the brake stack and the force member in the retracted position, (c) a sensor in communication with the brake stack to measure a force between the force member and the brake stack in response to the brake command, and (d) a brake control unit configured to determine a running clearance brake command defined as a percentage of a maximum braking force that causes the force member to contact the brake stack, wherein the running clearance brake command is determined based on the force measured by the sensor for a plurality of brake commands.

The present disclosure provides a brake system including (a) a brake stack, (b) a force member moveable between a retracted position and an extended position in response to a brake command, wherein the force member contacts the brake stack in the extended position, and wherein the brake system includes a running clearance defined by a distance between the brake stack and the force member in the retracted position, (c) a sensor in communication with the brake stack to measure a force between the force member and the brake stack in response to the brake command, and (d) a brake control unit configured to determine a running clearance brake command defined as a percentage of a maximum braking force that causes the force member to contact the brake stack, wherein the running clearance brake command is determined based on the force measured by the sensor for a plurality of brake commands.

An electronic circuit (12) connected to a variable-excitation sensor (24) and comprising: a digital envelope detector (20) arranged to acquire signal that is produced by the sensor in response to an excitation signal, the detector comprising: an analog-to-digital converter (22) arranged to sample the measurement signal in such a manner as to produce sample points during successive observation windows of duration T that comprise a number N.sub.S of sample points, the sample points being spaced apart by a sampling period T.sub.S, the sampling period T.sub.S and the duration T being such that:

T.sub.S=N.sub.P.Math.T.sub.0+(N.sub.T/N.sub.S).Math.T.sub.0 and T=N.sub.S.Math.T.sub.S,

where T.sub.0 is one excitation period of the excitation signal, where N.sub.P, N.sub.T, and N.sub.S are non-zero natural integers, and where N.sub.T is not a multiple of N.sub.S.

An electronic circuit (12) connected to a variable-excitation sensor (24) and comprising: a digital envelope detector (20) arranged to acquire signal that is produced by the sensor in response to an excitation signal, the detector comprising: an analog-to-digital converter (22) arranged to sample the measurement signal in such a manner as to produce sample points during successive observation windows of duration T that comprise a number N.sub.S of sample points, the sample points being spaced apart by a sampling period T.sub.S, the sampling period T.sub.S and the duration T being such that:

T.sub.S=N.sub.P.Math.T.sub.0+(N.sub.T/N.sub.S).Math.T.sub.0 and T=N.sub.S.Math.T.sub.S,

where T.sub.0 is one excitation period of the excitation signal, where N.sub.P, N.sub.T, and N.sub.S are non-zero natural integers, and where N.sub.T is not a multiple of N.sub.S.

A 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.

A 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.

The present invention is a system and method for evaluating runway conditions that combines known brake control systems with a new runway condition monitoring unit working in conjunction with an anti-skid/brake control unit to improve runway condition evaluation. The runway condition monitoring unit is installed on an airplane and receives data from the brake control unit, and processes that data through hardware and software to formulate a runway condition report of the airplane while landing on a runway. The invention may include additional sensors or interfaces that supplement the data received from the BCU. The runway condition monitoring unit contains a processor and interfaces that calculates and creates a runway condition report. The runway condition monitoring unit communicates the report by way of the avionics communication network on the airplane to devices that then send the runway condition report to consumers of the data, such as the flight deck, air traffic controllers, airport operators and airline operations.

The present invention is a system and method for evaluating runway conditions that combines known brake control systems with a new runway condition monitoring unit working in conjunction with an anti-skid/brake control unit to improve runway condition evaluation. The runway condition monitoring unit is installed on an airplane and receives data from the brake control unit, and processes that data through hardware and software to formulate a runway condition report of the airplane while landing on a runway. The invention may include additional sensors or interfaces that supplement the data received from the BCU. The runway condition monitoring unit contains a processor and interfaces that calculates and creates a runway condition report. The runway condition monitoring unit communicates the report by way of the avionics communication network on the airplane to devices that then send the runway condition report to consumers of the data, such as the flight deck, air traffic controllers, airport operators and airline operations.

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.

An aircraft includes a brake lever for receiving a pilot braking input as a lever travel of the brake lever, a braking wheel operatively coupled with the brake lever to brake the aircraft based on the lever travel, a brake actuator operatively coupled with the braking wheel to apply a braking force in response to a braking pressure provided to the brake actuator, and a brake pressure circuit. The brake pressure circuit is configured for: estimating a maximum braking pressure above which the braking wheel will skid with respect to a ground surface; scaling a lever gain of the brake lever to command the maximum braking pressure at a full travel of the brake lever such that a remaining brake lever travel indicates the amount of braking capability remaining for the aircraft; and braking the braking wheel based on the lever gain and the lever travel.