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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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04/02/21

Message Overview:

Message Name:

NO L-GP-5 BUS INPUT

Message Code:

B3-642552

Associated CAS:

None

Reporting LRU: TAWS MARK V
System Description: 34-42-00
Schematic Diagram: 34-42-00
Wiring Diagram: 31-45-06
34-42-01

Message Description:

L-GP-5 bus data absent at TAWS and NOT A-DCU or B-DCU; TAWS not in test.

Possible Causes:

  • Terrain-Avoidance Warning System (TAWS) Computer (A34)
  • Junction Box (JB2)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Junction Box JB2 AMM 24-63-05-000-803
Installation of the Junction Box JB2 AMM 24-63-05-400-803
Standard Practices - Replace Wiring SPM 20-12-00-02
Standard Practices - Repair Wiring SPM 20-12-10-02

Troubleshooting Recommendations:

  1. Reset TAWS (CB2-A6) circuit breaker or push in the TAWS TEST/RESET Switch on the center pedestal.

    1. If system check passes, do close out.
    2. If fault remains, continue with next step.

  2. Do the wiring check of the ARINC 429 data bus L-GP-5 from the TAWS computer connector A34BP1, through the Junction Box 2, to the DCU connector A14DP1. Repair/replace as required.

    1. If system check passes, do close out.
    2. If fault remains, continue with next step.

  3. Replace the TAWS computer.
  4. Do close out.

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