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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:

CROSSWIRED LOOPS

Message Code:

B3-008149

Associated CAS:

FIRE SYS FAULT
(Advisory)

Reporting LRU: L ENG FIRE LOOPS
System Description: 26-12-00
Schematic Diagram: 26-12-00
Wiring Diagram: 26-12-01

Message Description:

A and B fire detection loops on the left engine are cross wired. Check each elements wiring connection.

Possible Causes:

  • Engine Fire Detection are crossed
  • Fire Detection and Extinguishing (FIREX) Control Unit (A91)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Fire-Detection-and-Extinguishing (FIREX) Control-Unit AMM 26-11-01-000-801
Installation of the Fire-Detection-and-Extinguishing (FIREX) Control-Unit AMM 26-11-01-400-801
Removal of the Core Sensing Element AMM 26-12-01-000-801
Installation of the Core Sensing Element AMM 26-12-01-400-801
Removal of the Forward-Nacelle Sensing Element AMM 26-12-05-000-801
Installation of the Forward-Nacelle Sensing Element AMM 26-12-05-400-801
Removal of the Pylon Sensing Element AMM 26-12-09-000-801
Installation of the Pylon Sensing Element AMM 26-12-09-400-801
Removal of the Gearbox Sensing Element AMM 26-12-13-000-801
Installation of the Gearbox Sensing Element AMM 26-12-13-400-801
Electrical Bonding - Adjustment/Test SPM 51-80-00-05
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02

Troubleshooting Recommendations:

  1. Do LDE checks of the Left engine Loops A & B, if loops do not show continuity, inspect the suspected fire loops for proper installation, look for proper routing and distance from components.

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

  2. Perform the electrical bonding test.

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

  3. Replace FIREX CU.
  4. Do close out.

firex_block

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