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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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01/28/21

Message Overview:

L OUTBD BRAKE FAIL
(Caution)

DDG Reference: None
Pilot Action (QRH): GEAR 10-8
System Description: 32-43-00
Schematic Diagram: 32-43-00
Wiring Diagram: 32-43-09

Message Description:

The amber 'L OUTBD BRAKE FAIL' caution CAS message indicates the left outboard normal system brake has failed. The respective normal brake system has failed, either from a BCV fail, wheel speed transducer fail, hydraulic fuse or shuttle valve.

Possible Causes:

  • Left Outboard Brake Control Valve MPE24 (BCV)
  • Failed the Pressure Pulse Test at power-up or at gear down
  • Left Outboard Wheel Speed Transducer MT89
  • Left Pilot and Left Copilot Brake LVDT
  • Left Outboard Hydraulic Fuse
  • Left Outboard Shuttle Valve

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

  • One failure of the following components on the Left Outboard Brake will trigger an 'L OUTBD BRAKE FAIL' CAS message.

    • Brake Control Valve
    • Wheel Speed Transducer
    • Left Pilot and Left Copilot Brake LVDT
    • Hydraulic Fuse
    • Shuttle Valve

Download the MDC for fault isolation

Download the BCU NVM for the Outboard Channel

Quick Links:

Data Download from the Maintenance Diagnostic Computer (MDC) AMM 45-45-01-970-802
Removal of the Brake Control Valve AMM 32-43-09-000-801
Installation of the Brake Control Valve AMM 32-43-09-400-801
Removal of Wheel Speed Transducer AMM 32-43-49-000-801
Installation of Wheel Speed Transducer AMM 32-43-49-400-801
Removal of the Brake Pedal Position Transducer AMM 32-43-05-000-801
Installation of the Brake Pedal Position Transducer AMM 32-43-05-400-801
Removal of Hydraulic Fuse AMM 32-43-33-000-801
Installation of Hydraulic Fuse AMM 32-43-33-400-801
Removal of Shuttle Valve AMM 32-43-21-000-801
Installation of Shuttle Valve AMM 32-43-21-400-801

Troubleshooting Recommendations:

  1. Verify MDC faults for following messages.

    1. If MDC faults from Step 1 are showing, use drop down menu and troubleshoot according to specific B3 code.
    2. If MDC faults from Step 1 are not showing, continue with next step.

  2. Pressurize the hydraulic system.
  3. Enter MDC main menu and select system parameters and record pressure.
  4. Check the Left Outboard brake pressure.
  5. Reset the Left Outboard hydraulic fuse and hold the reset lever at the flow position.
  6. Press the pedal to the fully compressed position.

    1. If the Left Outboard brake pressure is higher than 2640 psi, go to step 8.
    2. If the Left Outboard brake pressure is lower than 2640 psi continue with next step.

  7. Replace the Left Outboard BCV (MPE24), do close out.
  8. Check for external leakage from the Left Outboard hydraulic fuse down to the Left Outboard brake.

    1. If there is no leakage, go to step 10.
    2. If there is leakage, continue with next step.

  9. Replace/Repair the leaking parts, do close out.
  10. Release the Left Outboard hydraulic fuse lever and keep the pedals pressed.

    1. If the "L Outbd Brake Fail" CAS message reappeared, continue with next step.
    2. If the "L Outbd Brake Fail" CAS message did not reappear, do close out.

  11. Replace the Left Outboard Shuttle Valve and repeat test from step 4.

    1. If the "L Outbd Brake Fail" CAS message reappeared, continue with next step.
    2. If the "L Outbd Brake Fail" CAS message did not reappear, do close out.

  12. Replace the Left Outboard Brake Hydraulic Fuse and repeat test from step 4.

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