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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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02/26/21

Message Overview:

Message Name:

CRIT FAIL RESET MISMATCH

Message Code:

B3-006686

Associated CAS:

FLAPS FAULT
(Advisory)

Reporting LRU: FLAP CTRL UNIT
System Description: 27-52-00
Schematic Diagram: 27-52-00
Wiring Diagram: 27-51-01

Message Description:

Flap Control Unit (FCU) detected a mismatch between control and monitor channel Critical Failure Reset discrete inputs. Check wiring and Critical Failure Reset Switch.

Possible Causes:

  • Critical Failure Reset Switch
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Flap Control Unit (FCU) AMM 27-51-05-000-801
Installation of the Flap Control Unit (FCU) AMM 27-51-05-400-801
Operational Test of the Flap Control Unit (FCU) AMM 27-51-05-710-801
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02
Electrical Connectors - Maintenance Practice - ALL SPM 20-20-00-02

Troubleshooting Recommendations:

  1. Attempt to reset the flaps using the Flap Reset on the left galley rotary test switch, near entry door. If unable to reset engage the Alternate Flaps button with the left hydraulic system pressurized, and attempt another reset using the Flap Reset switch on the left galley.

    1. If system checks are good, do close out.
    2. If unable to clear, continue with next step.

  2. Re-rack FCU.

    1. If system checks are good, do close out.
    2. If problem remains, continue to next step.

  3. Do wiring check between Critical Failure Reset Switch (Galley rotary test switch) and Flap Control Unit. Repair as necessary.

    1. If system checks are good, do close out.
    2. If unable to clear, continue with next step.

  4. Push to reset the flaps using the Galley rotary test switch and make sure ground is available at connector A124BP1 pin 6H and A124AP1 pin 3J. If not, replace the switch.

    1. If system checks are good, do close out.
    2. If problem remains, continue to next step.

  5. Replace FCU.

    1. If system checks are good, do close out.

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