Message Name:

HYDRAULIC FAULT INBOARD LEFT

Message Code:

3246017HA

Hydraulic fault is sensed for the Inboard Left Brake.

• Left Inboard Brake Pressure Transducer 2 (MT51)
• Inboard Brake Shutoff Valve (L13)
• Left Inboard Brake Control Valve (MT153)
• Brake Control Unit (A71)
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW700-32-0138 - Loss of Normal Braking Upon Landing
• AW700-32-0244 - Operational Procedures to Prevent Freezing Brakes
• AW700-32-0359 - Brake Control System - Data Gathering to Reduce the Brake Control Unit (BCU) No-Fault-Found (NFF) rate
• AW700-32-0513 - Wheel Speed Transducer - Brake System Nuisance Fault Messages
• SB700-32-016 - MODIFICATION - BRAKE CONTROL SYSTEM - PART NO. CHANGE OF THE BRAKE CONTROL UNIT TO GW415-7125-5

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

NOTES:

• If you replace a brake system component please fill out this questionnaire.

WARNING: MAKE SURE THE WHEEL CHOCKS ARE PUT AT THE NOSE AND MAIN WHEEL/TIRE ASSEMBLIES. MOVEMENT OF THE AIRCRAFT CAN CAUSE INJURY TO PERSONS AND DAMAGE TO THE EQUIPMENT.

WARNING: MAKE SURE THAT THE LOCKPINS ARE INSTALLED IN THE NOSE AND MAIN LANDING GEARS. THE NOSE AND MAIN LANDING GEARS CAN ACCIDENTALLY RETRACT. THIS CAN CAUSE INJURY TO PERSONS AND DAMAGE TO THE EQUIPMENT.

1. Pressurize the hydraulic systems 1, 2 and 3 with the applicable ACMPs.
2. Activate the BRAKE CONTROL SYSTEM page on the CAIMS PMAT display as follows:

   1. Access CAIMS System Diagnostics
   2. Select ATA 32-00 LANDING GEAR
   3. Select BRAKE CONTROL UNIT
   4. Select LRU TEST
   5. Select SYSTEM DATA PAGES
   6. Select CONFRM twice to go to BRAKE CONTROL SYSTEM DATA page 2

3. Apply maximum brakes at the brake pedals. Check that the pressure for each channel of the inboard left pressure transducers agree (less than ±25 psig differential pressure).

   1. If the pressures agree, go to step 5.
   2. If the pressures do not agree (more than ±25 psig differential pressure), continue with next step.

4. Interchange the left inboard pressure transducer with left outboard pressure transducer to confirm the fault.

   1. If the system checks are good, replace the left inboard pressure transducer and do close out.
   2. If the fault remains, continue with next step.

5. Release hydraulic pressure from the hydraulic systems 1, 2 and 3.
6. Interchange the left inboard brake control valve with the left outboard brake control valve.

   1. If the system checks are good, go to step 12.
   2. If the fault remains, continue with next step.

7. Perform the pressure pulse test with the CAIMS PMAT as follows:

   1. Access CAIMS System Diagnostics
   2. Select ATA 32-00 LANDING GEAR
   3. Select BRAKE CONTROL UNIT
   4. Select LRU TEST
   5. Select PRESSURE PULSE TEST CH A & CH B
   6. Follow the PRECONDITION and select CONFRM

8. Check if the CAIMS - HYDRAULIC FAULT INBOARD LEFT clears and the CAIMS - HYDRAULIC FAULT OUTBOARD LEFT comes on.
   NOTE: The defective brake control valve is now installed at the left outboard location.

   1. If the CAIMS - HYDRAULIC FAULT INBOARD LEFT clears and the CAIMS - HYDRAULIC FAULT OUTBOARD LEFT comes on, go to step 12.
   2. If the CAIMS - HYDRAULIC FAULT OUTBOARD LEFT does not clear, continue with next step.

9. Interchange the inboard brake shutoff valve with the outboard brake shutoff valve.

   1. If system checks are good, go to step 13.
   2. If fault remains, continue with next step.

10. Check if the CAIMS - HYDRAULIC FAULT INBOARD LEFT clears and the CAIMS - HYDRAULIC FAULT OUTBOARD LEFT comes on.
    NOTE: The defective brake shutoff valve is now installed at the outboard location.

    1. If the CAIMS - HYDRAULIC FAULT INBOARD LEFT clears and the CAIMS - HYDRAULIC FAULT OUTBOARD LEFT comes on, go to step 13.
    2. If the CAIMS - HYDRAULIC FAULT INBOARD LEFT does not clear, continue with next step.

11. Perform all wiring checks between the BCU and the related components (Inboard Brake SOV, Left Inboard BCV and Left Inboard Brake Pressure transducer).

    1. If wiring checks are not good, repair defective wiring as required and do close out.
    2. If wiring checks are good, continue with next step.

12. Replace left inboard brake control valve.

    1. If the system checks are good, do close out.
    2. If the fault remains, continue with next step.

13. Replace the inboard brake shutoff valve.

    1. If the system checks are good, do close out.
    2. If the fault remains, continue with next step.

14. Replace BCU. Make sure to review AW700-32-0359 and fill out the questionnaire.
15. Do close out.