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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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03/02/21

Message Overview:

Message Name:

INVALID WOW INPUT

Message Code:

B3-007968

Associated CAS:

None

Reporting LRU: STALL COMPUTER
System Description: 27-32-00
Schematic Diagram: 27-32-00
Wiring Diagram: 27-32-01
27-32-05
32-61-09

Message Description:

The WOW inputs from PSEU A and PSEU B miscompare or WOW inputs from SPC A and SPC B miscompare. Verify PSEU and aircraft wiring.

Possible Causes:

  • Proximity-Sensor Electronic Unit (PSEU) (A9)
  • Stall Protection Computer (SPC) (A178)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Operational Test of the Stall Protection System (SPS) AMM 27-32-00-710-801
Removal of the Stall Protection Computer AMM 27-32-01-000-801
Installation of the Stall Protection Computer AMM 27-32-01-400-801
Removal of the Proximity-Sensor Electronic Unit (PSEU) AMM 32-61-09-000-801
Installation of the Proximity-Sensor Electronic Unit (PSEU) AMM 32-61-09-400-801
Functional Test of the Proximity-Sensor Electronic Unit (PSEU) AMM 32-61-09-720-801
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. Do the operational test of the WOW proximity sensors PX01, PX02, PX03, PX31, PX32 and PX33.

    1. If test passes, go to step 4.
    2. If test fails, continue with next step.

  2. Do wiring check of related sensors.
  3. Replace defective sensor as required.

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

  4. Re-rack PSEU.

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

  5. Reset the SPC circuit breakers 'SPC CH A' (CBP1-B10) and 'SPC CH B' (CBP2-10).

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

  6. Re-rack SPC.

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

  7. Do wiring checks between SPC connector A178BP1 and PSEU A9AP1.

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

  8. Replace SPC.
  9. Do close out.

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