background
x
loader
Troubleshooting
arrow By ATA By Message Color By Observed Faults by MDCBy Tips

Select color for CAS message that you wish to troubleshoot

(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.

This page includes :

For AOG assistance contact:

CRC Montreal (YUL)
Quick Links

04/26/21

Message Overview:

Message Name:

INTEGRATED STANDBY INSTRUMENT (ISI) DOES NOT POWER UP

Identifier: 341OBS013
Effectivity: AIRCRAFT 20501 - 20999
System: Standby Air Data System
System Description: 34-12-00
Schematic Diagram: 34-12-00
Wiring Diagram: 34-12-01

Message Description:

Integrated Standby Instrument (ISI) fails to power up when selected ON.

Possible Causes:

  • Integrated Standby Instrument (ISI) (A90)
  • Standby Instrument Battery (BT3)
  • Standby Instrument Switch (SDS68)
  • Associated Wiring

Troubleshooting Tips:

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

Quick Links:

Removal of the Standby Instrument Battery AMM 24-32-05-000-801
Installation of the Standby Instrument Battery AMM 24-32-05-400-801
Removal of the Integrated Standby Instrument AMM 34-12-01-000-801
Installation of the Integrated Standby Instrument AMM 34-12-01-400-801
Wire Repair - Maintenance Practices - ALL SPM 20-12-10-02

Troubleshooting Recommendations:

  1. Select the STBY INST switch to ON from the Electrical System Control Panel. Does the ISI power up?

    1. If YES, do close out.
    2. If NO, continue with next step.

  2. Set the Right Battery power to ON. Does the ISI power up?

    1. If YES, replace the ISI Battery (BT3)
    2. If NO, continue with next step.

  3. Disconnect the electrical control panel connector PL14P2. Perform a 28 VDC voltage as follows:

    From To Result
    PL14P2-4 Ground

    1. If 28 VDC is present, go to step 5.
    2. If 28 VDC is missing, continue with next step.

  4. Perform a continuity check between the control panel and the ISI battery as follows:

    From To Result
    PL14P2-4 BT3P1-24

    1. If there is continuity, replace ISI battery and do close out.
    2. If there is no continuity, repair defective wiring and do close out.

  5. Perform a continuity check across the STBY INST switch as follows:

    From To Result
    PL14J2-4 PL14J2-6

    1. When the switch is set to "ON", if there is continuity, reconnect the electrical control panel and continue with next step.
    2. If there is no continuity, replace defective switch.

  6. Perform a 28 VDC voltage check at ISI connector A90P1 pin D.

    1. If 28 VDC is present, replace the ISI.
    2. If 28 VDC is missing, perform wiring check between the ISI and the control panel and repair defective wiring as required.

  7. Do close out.

Registered and/or unregistered trademarks of Bombardier Inc. or its subsidiaries. © 2015 Bombardier Inc. All rights reserved.