background
x
loader
Troubleshooting
arrow By ATA By Message Color By Observed Faults by MDCBy Tips

Select color for CAS message that you wish to troubleshoot

(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.

This page includes :

For AOG assistance contact:

CRC Montreal (YUL)
Quick Links

05/06/21

Message Overview:

Message Name:

RIGHT OB BRAKE HYDRAULIC

Message Code:

B3-007836

Associated CAS:

L OUTBD BRAKE FAIL
(Caution)

OUTBD BRAKES FAIL
(Caution)

R OUTBD BRAKE FAIL
(Caution)

Reporting LRU: R OB BRAKE HYDR
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 outboard brake hydraulic control, or the outboard brake control unit.

Possible Causes:

  • Brake Control Unit (BCU) (A67)
  • Right Brake Control Valve (BCV) (MPE24)
  • Right Brake Shut-Off Valve (BSOV) (MPE28)
  • Right Outboard Brake Pressure Transducer (MT98)
  • 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 - Continuity 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 RCBP-C15 (OUTBD BRAKES) after having recharged the accumulators.

    1. Reset circuit breaker RCBP-C15 (OUTBD BRAKES).
    2. After 30 seconds, if the '(L) (R) OUTBD BRAKE FAIL' CAS message IS NOT shown, go to step 2. D.
    3. After 30 seconds, if the '(L) (R) OUTBD 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 outboard brake pressure indications.

      1. If both the left and right outboard 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) OUTBD BRAKE FAIL' CAS message IS NOT displayed, go to step 3. C.
      4. If both brake pressure increase and the '(L) (R) OUTBD 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 outboard brake pressures did not increase, do the following:

      1. Inspect inboard shut-off valve wiring and connector.

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

      2. Interchange inboard and outboard shut-off valves.
      3. Carry out the 'FAULT CONFIRMATION' section.

        1. If the fault followed to the inboard side, replace faulty shut-off valve.
        2. If the fault did not follow to the outboard side, replace BCU.

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

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

        1. If test fails, inspect outboard brake control valve connector and wiring. If no fault found, replace the outboard 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. Interchange the inboard and outboard brake control valves and carry out the 'FAULT CONFIRMATION' section.

        1. If the fault followed to the inboard, replace the faulty brake control valve.
        2. If the fault did not follow, replace BCU.

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

      1. Pressurize the right hydraulic system.

        1. If the '(L) (R) OUTBD 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 outboard 'HARDWARE MONITOR TEST'.

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

      4. Depressurize the right hydraulic system.
      5. Carry out the outboard BCU 'EPROM TEST'.

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

      6. Do a leak check of the outboard 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 outboard brake control valve connector and wiring. If no fault found, replace the outboard BCV.
        2. If test pass, go to next step.

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

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

      4. Interchange 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 RCBP-C15 (OUTBD BRAKES).
      6. Gradually apply the left brake pedal.
      7. If the '(L) (R) OUTBD BRAKE FAIL' CAS message is displayed, reset circuit breaker RCBP-C15 (OUTBD 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) OUTBD BRAKE FAIL' CAS message to be displayed, replace BCU.
        2. If only 1 brake pedal application caused the '(L) (R) OUTBD BRAKE FAIL' CAS message to be displayed, interchange the outboard left and outboard right pressure transducers.

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

  4. Do close out.

Registered and/or unregistered trademarks of Bombardier Inc. or its subsidiaries. © 2015 Bombardier Inc. All rights reserved.