Dual redundant active/active brake-by-wire architecture

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having right and left main landing gear and center landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes- for the plurality of wheels, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising a plurality of primary hydraulic fluid control channels and a plurality of secondary hydraulic fluid control channels, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and being redundant and partitioned among said plurality of wheel brakes so that even if both the primary and secondary hydraulic fluid control channels fail to apply pressure, braking will be lost to only a portion of the wheel brakes and the loss will be in a symmetrical pattern;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system providing dual redundant analog brake-by-wire control in the alternate braking mode for the right and left main and center landing gears of the aircraft, and said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off;
• and
• a landing gear lever controlling retraction of the landing gear, and dual redundant switches on the landing gear lever to bypass the thrust lever switches to stop the wheels during climb when the thrust levers are advanced to enable wheel braking upon retraction of the landing gear.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having right and left main landing gear and center landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising a plurality of primary hydraulic fluid control channels and a plurality of secondary hydraulic fluid control channels, the primary-and secondary hydraulic fluid control channels operating simultaneously and autonomously, and being redundant and partitioned among said plurality of wheel brakes so that even if both the primary and secondary hydraulic fluid control channels fail to apply pressure, braking will be lost to only a portion of the wheel brakes and the loss will be in a symmetrical pattern;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system providing dual redundant analog brake-by-wire control in the alternate braking mode for the right and left main and center landing gears of the aircraft, and said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off;
• wherein said control unit further comprises a plurality of sensors for sensing the position of each said brake pedal, and wherein said plurality of sensors comprises dual redundant switches that break both power and ground to said first and second solenoid operated shut-off valves, such that depression of one of said brake pedals opens the first and second solenoid operated shut-off valve for one of the primary hydraulic system in the normal braking mode and the secondary hydraulic system in the alternate braking mode.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having right and left main landing gear and center landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising a plurality of primary hydraulic fluid control channels and a plurality of secondary hydraulic fluid control channels, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and being redundant and partitioned among said plurality of wheel brakes so that even if both the primary and secondary hydraulic fluid control channels fail to apply pressure, braking will be lost to only a portion of the wheel brakes and the loss will be in a symmetrical pattern;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system providing dual redundant analog brake-by-wire control in the alternate braking mode for the right and left main and center landing gears of the aircraft, and said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• and
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off;
• wherein said first and second solenoid operated shut-off valves also turn off hydraulic power to said servo control valves during flight.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having right and left main landing gear and center landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising a plurality of primary hydraulic fluid control channels and a plurality of secondary hydraulic fluid control channels, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and being redundant and partitioned among said plurality of wheel brakes so that even if both the primary and secondary hydraulic fluid control channels fail to apply pressure, braking will be lost to only a portion of the wheel brakes and the loss will be in a symmetrical pattern;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system providing dual redundant analog brake-by-wire control in the alternate braking mode for the right and left main and center landing gears of the aircraft, and said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• and
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off;
• wherein said control unit further comprises means for sensing weight on said plurality of wheels and for generating a brake inhibit signal when weight is not applied on said plurality of wheels.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising a plurality of primary hydraulic fluid control channels and a plurality of secondary hydraulic fluid control channels, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• and
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut- off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off;
• and
• a landing gear lever controlling retraction of the landing gear, and dual redundant switches on the landing gear lever to bypass the thrust lever switches to stop the wheels during climb when the thrust levers are advanced to enable wheel braking upon retraction of the landing gear.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• and
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut- off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off;
• wherein said first and second solenoid operated shut-off valves also turn off hydraulic power to said servo control valves during flight.

In combination with an aircraft, an apparatus for dual redundant control of hydraulically operated wheel braking for the aircraft, the aircraft having landing gear that can move between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel, the primary and secondary hydraulic fluid control channels operating simultaneously and autonomously, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode, said secondary hydraulic system comprising at least one primary hydraulic fluid control channel and at least one secondary hydraulic fluid control channel;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary and secondary hydraulic systems for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time, wherein said control unit comprises thrust levers, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the primary or secondary hydraulic systems during take off, and
• wherein said control unit further comprises means for sensing weight on said plurality of wheels and for generating a brake inhibit signal when weight is not applied on said plurality of wheels.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously with and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• and
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel-brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time;
• wherein said control unit comprises thrust levers and corresponding thrust lever switches, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the normal or alternate brake metering systems during take off;
• and
• a landing gear lever controlling retraction of the landing gear, and dual redundant switches on the landing gear lever to bypass the thrust lever switches to stop the wheels during climb when the thrust levers are advanced to enable wheel braking upon retraction of the landing gear.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time;
• wherein said control unit comprises thrust levers and corresponding thrust lever switches, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the normal or alternate brake metering systems during take off;
• and
• wherein said control unit comprises a plurality of servo control valves controlled by corresponding dual solenoid coils for controlling the operation of said wheel brakes, respectively, and wherein said thrust levers comprise dual thrust lever switches that break both power and ground to said first and second solenoid operated shut-off valves for the primary hydraulic system and secondary hydraulic system when a thrust lever is advanced.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time;
• wherein said control unit comprises thrust levers and corresponding thrust lever switches, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the normal or alternate brake metering systems during take off;
• wherein said control unit further comprises a plurality of sensors for sensing the position of each brake pedal, and wherein said sensors comprise dual redundant switches that break both power and ground to said first and second solenoid operated shut-off valves, such that depression of either brake pedal opens the first and second solenoid operated shut-off valve for the active hydraulic system.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for a selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time;
• wherein said control unit comprises thrust levers and corresponding thrust lever switches, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the normal or alternate brake metering systems during take off;
• and
• wherein said first and second solenoid operated shut-off valves also turn off hydraulic power to said servo control valves during flight.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• first and second solenoid operated shut-off valves operatively connected to said primary and secondary hydraulic systems, respectively, and to said control unit for selecting operation of one of said primary and secondary hydraulic systems, said first and second solenoid operated shut-off valves being configured to operate in a mutually exclusive manner to positively select between operation of said primary and secondary hydraulic systems without the possibility of having both systems pressurized at the same time;
• wherein said control unit comprises thrust levers and corresponding thrust lever switches, and said solenoid operated shut-off valves are implemented through said thrust levers to positively prevent pressure from the primary hydraulic system and secondary hydraulic system being applied to the normal or alternate brake metering systems during take off;
• and
• wherein said control unit further comprises means for sensing weight on said wheel and for generating a brake inhibit signal when weight is not applied on said wheel.

In combination with aircraft landing gear, an apparatus for redundant control of hydraulically operated wheel braking for the aircraft landing gear moving between a retracted position and an actuated position, the landing gear having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels, wherein said plurality of wheel brakes are symmetrically divided into three sets of wheel brakes, and a plurality of brake pedals for controlling operation of braking of said plurality of said wheels, said apparatus comprising:

• a primary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for normal operation of said plurality of wheel brakes in a normal braking mode, said primary hydraulic system including a plurality of primary hydraulic fluid control channels and a corresponding plurality of secondary hydraulic fluid control channels, said plurality of secondary hydraulic fluid control channels operating simultaneously and independently from said plurality of primary hydraulic fluid control channels, and wherein said primary hydraulic system comprises first, second and third redundant pairs of primary and secondary fluid control channels, said first redundant pair of primary and secondary fluid control channels including a first primary hydraulic fluid control channel and a first secondary hydraulic fluid control channel, each of said first primary and said first secondary hydraulic fluid control channels controlling said first set of wheel brakes, said second redundant pair of primary and secondary fluid control channels including a second primary hydraulic fluid control channel and a second secondary hydraulic fluid control channel, each of said second primary and said second secondary hydraulic fluid control channels controlling said second set of wheel brakes, said third redundant pair of primary and secondary fluid control channels including a third primary hydraulic fluid control channel and a third secondary hydraulic fluid control channel, each of said third primary and said third secondary hydraulic fluid control channels controlling said third set of wheel brakes;
• a secondary hydraulic system connected in fluid communication with said plurality of wheel brakes for providing hydraulic power for operation of said plurality of wheel brakes in an alternate braking mode;
• a control unit for controlling brake pressure communicated to said wheel brakes through said primary and secondary hydraulic systems;
• a monitor channel operatively connected to said primary hydraulic system for detecting faults in said primary and secondary hydraulic systems and for selecting between the primary and secondary hydraulic systems for providing braking pressure;
• and
• wherein said control unit comprises system six brake control cards providing dual redundant digital brake-by-wire controls.