Method to reduce carbon brake wear through residual brake force

1. A method for controlling carbon brakes of an aircraft having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels to reduce brake wear when the aircraft is taxiing, comprising the steps of:

monitoring commanded initiation of braking of any of the plurality of wheel brakes of the aircraft;

setting a residual brake clamping force to a predetermined minimum residual brake clamping force for the plurality of wheel brakes only in response to said commanded initiation of braking of any of the plurality of wheel brakes;

applying said predetermined minimum residual brake clamping force simultaneously to all of the plurality of wheel brakes despite a commanded release of braking of any of the plurality of wheel brakes;

determining an average wheel speed and comparing said average wheel speed with a predetermined wheel speed threshold; and

discontinuing applying said predetermined minimum residual brake clamping force in response to at least one control logic condition, wherein said at least one control logic condition comprises when said average wheel speed is below said predetermined wheel speed threshold.

2. The method of claim 1 , wherein said predetermined wheel speed threshold is in the range of about 2 knots to about 15 knots.

3. The method of claim 1 , wherein said predetermined wheel speed threshold is in the range of about 2 knots to about 10 knots.

4. The method of claim 1 , wherein said aircraft has left and right landing gear, and said step of determining an average wheel speed comprises determining an average wheel speed of the left landing gear and an average wheel speed of the right landing independently, comparing said average wheel speeds of the left and right landing gear, and comparing the lesser of the average wheel speeds of the left and right landing gear with said predetermined wheel speed threshold.

5. The method of claim 1 , wherein said aircraft includes at least one engine thrust lever, further comprising the step of monitoring engine thrust lever position, and wherein said at least one control logic condition comprises when said at least one engine thrust lever is in an advanced position.

6. The method of claim 1 , further comprising the step of detecting wheel speed acceleration, and comparing said wheel speed acceleration with a predetermined acceleration threshold, and wherein said at least one control logic condition comprises when said wheel speed acceleration exceeds said acceleration threshold.

7. The method of claim 1 , further comprising monitoring temperature of said plurality of wheel brakes, and comparing said temperature of said plurality of wheel brakes with a temperature threshold, and wherein said at least one control logic condition comprises when said temperature of said plurality of wheel brakes exceeds said temperature threshold.

8. The method of claim 1 , further comprising determining distance rolled with said predetermined minimum residual brake clamping force applied, comparing said distance rolled with a predetermined distance threshold, and wherein said at least one control logic condition comprises when said distance rolled exceeds said predetermined distance threshold.

9. The method of claim 1 , wherein said predetermined minimum residual brake clamping force comprises about 1-10% of a maximum brake clamping force of said plurality of wheel brakes.

10. The method of claim 1 , wherein said predetermined minimum residual brake clamping force comprises about 1-5% of a maximum brake clamping force of said plurality of wheel brakes.

11. A method for controlling carbon brakes of an aircraft having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels to reduce brake wear when the aircraft is taxiing, comprising the steps of:

monitoring commanded initiation of braking of any of the plurality of wheel brakes of the aircraft;

setting a residual brake clamping force to a predetermined minimum residual brake clamping force for all of the plurality of wheel brakes only in response to said commanded initiation of braking of any of the plurality of wheel brakes;

monitoring commanded release of braking of any of the plurality of wheel brakes of the aircraft;

applying said predetermined minimum residual brake clamping force simultaneously to all of the plurality of wheel brakes following said commanded release of braking of any of the plurality of wheel brakes;

determining an average wheel speed; and

setting said residual brake clamping force to zero when said average wheel speed is in the range of a predetermined wheel speed threshold of about 2 knots to about 15 knots.

12. The method of claim 11 , wherein said aircraft has left and right landing gear, and said step of determining an average wheel speed comprises determining an average wheel speed of the left landing gear and an average wheel speed of the right landing independently, comparing said average wheel speeds of the left and right landing gear, and comparing the lesser of the average wheel speeds of the left and right landing gear with said predetermined wheel speed threshold.

13. The method of claim 11 , wherein said predetermined minimum residual brake clamping force comprises about 1-10% of a maximum brake clamping force of said plurality of wheel brakes.

14. The method of claim 11 , wherein said predetermined minimum residual brake clamping force comprises about 2-5% of a maximum brake clamping force of said plurality of wheel brakes.

15. A method for controlling carbon brakes of an aircraft having at least one engine thrust lever, a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels to reduce brake wear when the aircraft is taxiing, comprising the steps of:

monitoring commanded initiation of braking of any of the plurality of wheel brakes of the aircraft;

setting a residual brake clamping force to a predetermined minimum residual brake clamping force for all of the plurality of wheel brakes only in response to said commanded initiation of braking of any of the plurality of wheel brakes;

monitoring commanded release of braking of any of the plurality of wheel brakes of the aircraft;

applying said predetermined minimum residual brake clamping force simultaneously to all of the plurality of wheel brakes following said commanded release of braking of any of the plurality of wheel brakes;

monitoring engine thrust lever position; and

setting said residual brake clamping force to zero when said at least one engine thrust lever is in an advanced position.

16. A method for controlling carbon brakes of an aircraft having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels to reduce brake wear when the aircraft is taxiing, comprising the steps of:

monitoring commanded initiation of braking of any of the plurality of wheel brakes of the aircraft;

setting a residual brake clamping force to a predetermined minimum residual brake clamping force for all of the plurality of wheel brakes only in response to said commanded initiation of braking of any of the plurality of wheel brakes;

monitoring commanded release of braking of any of the plurality of wheel brakes of the aircraft;

applying said predetermined minimum residual brake clamping force simultaneously to all of the plurality of wheel brakes following said commanded release of braking of any of the plurality of wheel brakes;

detecting wheel speed acceleration, and comparing said wheel speed acceleration with a predetermined acceleration threshold; and

setting said residual brake clamping force to zero when said wheel speed acceleration exceeds said acceleration threshold.

17. A method for controlling carbon brakes of an aircraft having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels to reduce brake wear when the aircraft is taxiing, comprising the steps of:

monitoring commanded initiation of braking of any of the plurality of wheel brakes of the aircraft;

setting a residual brake clamping force to a predetermined minimum residual brake clamping force for all of the plurality of wheel brakes only in response to said commanded initiation of braking of any of the plurality of wheel brakes;

monitoring commanded release of braking of any of the plurality of wheel brakes of the aircraft;

applying said predetermined minimum residual brake clamping force simultaneously to all of the plurality of wheel brakes following said commanded release of braking of any of the plurality of wheel brakes;

monitoring temperature of said plurality of wheel brakes, and comparing said temperature of said plurality of wheel brakes with a temperature threshold; and

setting said residual brake clamping force to zero when said temperature of said plurality of wheel brakes exceeds said temperature threshold.

18. A method for controlling carbon brakes of an aircraft having a plurality of wheels and a corresponding plurality of wheel brakes for the plurality of wheels to reduce brake wear when the aircraft is taxiing, comprising the steps of:

monitoring commanded initiation of braking of any of the plurality of wheel brakes of the aircraft;

setting a residual brake clamping force to a predetermined minimum residual brake clamping force for all of the plurality of wheel brakes only in response to said commanded initiation of braking of any of the plurality of wheel brakes;

monitoring commanded release of braking of any of the plurality of wheel brakes of the aircraft;

applying said predetermined minimum residual brake clamping force simultaneously to all of the plurality of wheel brakes following said commanded release of braking of any of the plurality of wheel brakes;

determining distance rolled with said predetermined minimum residual brake clamping force applied, and comparing said distance rolled with a predetermined distance threshold; and

setting said residual brake clamping force to zero when said distance rolled exceeds said predetermined distance threshold.