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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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05/06/21

Message Overview:

Message Name:

DPMS8 OR WIRING FAULT

Message Code:

B3-226908

Associated CAS:

APU GEN FAIL
(Caution)

ELECTRICAL FAULT
(Caution)

ELECTRICAL FAULT
(Advisory)

Reporting LRU: DIFF PROT SNSR 8
System Description: 24-31-00
24-64-00
Schematic Diagram: 24-31-10
24-61-00
Wiring Diagram: 24-31-09
24-64-01

Message Description:

The Auxiliary Power Unit Sensor DPMS 8 has detected a current imbalance between the 2 feeders.
A failure with the Auxiliary Power Unit Sensor DPMS 8 has been detected by the Aux DCPC.
NOTE: When DPMS 8 failure occurs, the APU generator will feed the LH MAIN BUS by default.

Possible Causes:

  • Auxiliary Power Unit Sensor (DPMS8)
  • Auxiliary Power Unit Power Feeders (SBZ0002-1 and SBZ0003-1)
  • Terminal studs hardware loose
  • Auxiliary Power Center (Aux DCPC) (A196)
  • Right DC Power Center (RDCPC) (A36)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin:

  • AW300-24-0024 - Electrical System - Troubleshooting Tips
  • AW300-24-0137 - Y06 Electrical System Upgrade
  • AW300-24-0222 - Aft Fuselage - APU Generator Power Feeder Cable Fouling Condition (20501 - 20635)

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the DC Power Center (DCPC) AMM 24-61-01-000-801
Installation of the DC Power Center (DCPC) AMM 24-61-01-400-801
Removal of the Auxiliary DC Power Center (Aux DCPC) AMM 24-64-01-000-801
Installation of the Auxiliary DC Power Center (Aux DCPC) AMM 24-64-01-400-801
Removal of the Auxiliary Power Unit Sensor AMM 24-64-17-000-801
Installation of the Auxiliary Power Unit Sensor AMM 24-64-17-400-801
Wiring - Maintenance Practices - ALL SPM 20-12-00-02
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02

Troubleshooting Recommendations:

  1. Access the APU DCPC terminal studs T34 and T36, remove hardware, clean terminal studs / lugs and reinstall hardware. Make sure terminal studs lock nuts are torqued to specs.
  2. Access the RH DCPC terminal studs T84 and T86, remove hardware, clean terminal studs / lugs and reinstall hardware. Make sure terminal studs lock nuts are torqued to specs.
  3. Access the Auxiliary Power Unit Sensor DPMS8, make sure its hardware is torqued to specs.
  4. Disconnect the Auxiliary Power Unit Sensor DPMS8 connector. Do visual inspection of the connector and associated wiring for any loose pins and/or damaged wire.

    1. If inspection is satisfying, continue with next step.
    2. If inspection is not satisfying, go to step 6.

  5. Interchange the Auxiliary Power Unit Sensor DPMS8 with Auxiliary Power Unit Sensor DPMS7. Is the fault message still present?

    1. If YES, continue with next step.
    2. If NO, replace the defective Auxiliary Power Unit Sensor.

  6. Replace the electrical power feeders SBZ0002-1 and SBZ0003-1. Is the fault message still present?

    1. If YES, continue with next step.
    2. If NO, replace the defective Auxiliary Power Unit Sensor.
      NOTE: Harness assembly PN 1009109786-001 includes both power feeders and wire SBZ0001-1. SBZ0001-1 can also be replaced at your convenience.

  7. Replace the Aux DCPC (A196). Is the fault message still present?

    1. If YES, continue with next step.
    2. If NO, go to step 8.

  8. Replace the R DCPC (A35).
  9. Do close out.

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