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(WARNING)
RED MESSAGE (CAUTION)
AMBER MESSAGE (ADVISORY)
CYAN MESSAGE (STATUS)
WHITE MESSAGE Require immediate crew attention. These messages are accompanied by flashing master warning, triple chime attenson with or without voice message or dedicated tone. Require immediate crew awareness and future crew action may be required in the form of alternate system selection or performance limitation. These message are accompanied by flashing master caution and a single chime. Indicate safe or normal system operation which require crew awareness, over and above the dark cockpit philosophy. Indicate minor failures or reduction in systems capability, which require no crew action.

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03/10/21

Message Overview:

Message Name:

L IB BRAKE PRESS PULSE

Message Code:

B3-007102

Associated CAS:

INBD BRAKES FAIL
(Caution)

L INBD BRAKE FAIL
(Caution)

R INBD BRAKE FAIL
(Caution)

Reporting LRU: L IB BK PR PULSE
System Description: 32-43-00
Schematic Diagram: 32-43-00
Wiring Diagram: 32-43-01

Message Description:

The Brake Control Unit has detected a fault with the inboard brake hydraulic control, or the inboard brake control unit.

NOTE: Each of these fault codes can be the cause of, or consequence of one another, depending in which ordered they were logged. This troubleshooting procedure applies whether only one or a combination of these codes is logged.

Possible Causes:

  • Brake Control Unit (BCU) (A67)
  • Left Brake Control Valve (BCV) (MPE23)
  • Left Brake Shut-Off Valve (BSOV) (MPE27)
  • Left Break Pressure Transducer (MT97)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Brake Control Unit AMM 32-43-01-000-801
Installation of the Brake Control Unit AMM 32-43-01-400-801
Removal of the Brake Control Valve AMM 32-43-09-000-801
Installation of the Brake Control Valve AMM 32-43-09-400-801
Operational Test of the Brake Control Valve Resistance AMM 32-43-09-710-801
Removal of the Brake Pressure Transducer AMM 32-43-17-000-801
Installation of the Brake Pressure Transducer AMM 32-43-17-400-801
Removal of the Brake Shutoff Valve AMM 32-43-25-000-801
Installation of the Brake Shutoff Valve AMM 32-43-25-400-801
Removal of the Brake Hydraulic Fuse AMM 32-43-33-000-801
Installation of the Brake Hydraulic Fuse AMM 32-43-33-400-801
Removal of the Wheel Speed Transducer AMM 32-43-49-000-801
Installation of the Wheel Speed Transducer AMM 32-43-49-400-801
Data Download from the Maintenance Diagnostic Computer (MDC) AMM 45-45-01-970-802
Standard Practices - Replace Wiring SPM 20-12-00-02
Standard Practices - Electrical Wiring - Continuity Test - Adjustment/Test SPM 20-12-01-05
Standard Practices - Wire Repair SPM 20-12-10-02

Troubleshooting Recommendations:

NOTE: If assistance is required, send a download of the BCU NVM to Bombardier CRC for analysis.

  1. SETUP:

    1. Pressurize the left and right hydraulic systems.
    2. Make sure the inboard and outboard brake accumulators are charged (inboard and outboard brakes 'PRESS NORM' indication is green on the hydraulic synoptic page).
    3. Depressurize the left and right hydraulic systems.

  2. FAULT CONFIRMATION:
    NOTE: Do not re-pressurize the hydraulic systems during this procedure. This is to ensure that the BCU does not perform the power up hydraulic test sequence. If the inboard or outboard brake 'PRESS NORM' indication becomes amber during the procedure, reset circuit breaker LCBP-C15 (INBD BRAKES) after having recharged the accumulators.

    1. Reset circuit breaker LCBP-C15 (INBD BRAKES).
    2. After 30 seconds, if the '(L) (R) INBD BRAKE FAIL' CAS message IS NOT shown, go to step 2. D.
    3. After 30 seconds, if the '(L) (R) INBD BRAKE FAIL' CAS message IS shown, do the following:

      1. Access the MDC system parameters page.

        1. If the left or right inboard pressure indication is over 250 psi, replace pressure transducer.
        2. If the left or right inboard pressures is between 130 and 250 psi, read the following note and go to step 2. D.
          NOTE: While pressures between 130 psi and 250 psi are not the cause the CAS message, it is abnormal to have pressure in this range with no brake pedal input. Consider investigating.

          1. With BCU PN 142-045-1, the brake control valve may have a high internal leakage, or the pressure transducer may be faulty.
          2. With BCU PN 142-045-2, the pressure transducer may be faulty.

      2. If pressures are below 130 psi, go to step 2. D.

    4. Access the MDC system parameters page.
    5. Gradually apply the left and right brake pedals while observing the left and right inboard brake pressure indications.

      1. If both the left and right inboard brake pressures do not increase, go to step 3. A.
      2. If only one brake pressure increases, go to step 3. B.
      3. If both brake pressure increase and the '(L) (R) INBD BRAKE FAIL' CAS message IS NOT displayed, go to step 3. C.
      4. If both brake pressure increase and the '(L) (R) INBD BRAKE FAIL' CAS message IS displayed, go to step 3. D.
        NOTE: Pressures may decrease when the fault message appears.

  3. FAULT ISOLATION

    1. If both the left and right inboard brake pressures did not increase, do the following:

      1. Inspect inboard shutoff valve wiring and connector.

        1. Repair as required.
        2. If no fault is found, go to next step.

      2. Swap inboard and outboard shutoff valves.
      3. Carry out the 'FAULT CONFIRMATION' section.

        1. If the fault followed to the outboard side, replace faulty shutoff valve.
        2. If the fault did not follow to the outboard side, replace BCU.

    2. If only one inboard brake pressure increased, do the following:

      1. Access the MDC LRU TEST page.
      2. Carry out the inboard 'BCV RESISTANCE TEST'.

        1. If test fails, inspect inboard brake control valve connector and wiring. If no fault found, replace the inboard BCV.
        2. If test passes, go to next step.

      3. Have a second person action and hold the brake hydraulic fuse bypass lever of the brake that did not show a pressure increase.
      4. Apply the relevant brake pedal and observe the brake pressure indication.

        1. If pressure increases, do the following:

          1. Carry out a leak check downstream of the brake hydraulic fuse.
          2. If no leak is found, replace brake hydraulic fuse.

        2. If pressure does not increase, go to next step.

      5. Swap the inboard and outboard brake control valves and carry out the 'FAULT CONFIRMATION' section.

        1. If the fault followed to the outboard, replace the faulty brake control valve.

        1. If the fault did not follow, replace BCU.

    3. If both brake pressure increased and the '(L) (R) INBD BRAKE FAIL' CAS message was NOT displayed, do the following:

      1. Pressurize the left hydraulic system.

        1. If the '(L) (R) INBD BRAKE FAIL' CAS message is displayed, replace BCU.
        2. If not, go to next step.

      2. Access the MDC LRU TEST page.
      3. Carry out the inboard 'HARDWARE MONITOR TEST'.

        1. If test fails, replace BCU.
        2. If test pass, go to next step.

      4. Depressurize the left hydraulic system.
      5. Carry out the inboard BCU 'EPROM TEST'.

        1. If test fails, replace BCU.
        2. If test pass, go to next step.

      6. Do a leak check of the inboard brake system. If no leak found, there is no fault in the system.

    4. If both brake pressure increased and the '(L) (R) OUTBD BRAKE FAIL' CAS message was displayed, do the following:

      1. Access the MDC LRU TEST page.
      2. Carry out the inboard 'BCV RESISTANCE TEST'.

        1. If test fails, inspect inboard brake control valve connector and wiring. If no fault found, replace the inboard BCV.
        2. If test pass, go to next step.

      3. Do a leak check of the inboard brake system.

        1. Repair as required.
        2. If no leak found, go to next step.

      4. Swap the inboard and outboard brake control valves and carry out the 'FAULT CONFIRMATION' section.

        1. If problem followed to the outboard brakes, replace faulty brake control valve.
        2. If problem did not follow, go to next step.

      5. Reset circuit breaker LCBP-C15 (INBD BRAKES).
      6. Gradually apply the left brake pedal.
      7. If the '(L) (R) INBD BRAKE FAIL' CAS message is displayed, reset circuit breaker LCBP-C15 (INBD BRAKES) and go to next step.
      8. Gradually apply the right brake pedal.

        1. If both left and right brake pedal application caused the '(L) (R) INBD BRAKE FAIL' CAS message to be displayed, replace BCU.
        2. If only 1 brake pedal application caused the '(L) (R) INBD BRAKE FAIL' CAS message to be displayed, swap the inboard left and inboard right pressure transducers.

          1. If problem follows, replace faulty pressure transducer.
          2. If problem does not follow, replace BCU.

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