06/22/21
Message Overview:
Message Name:
INERTIAL REFERENCE SYSTEM (IRS) COOLING FANS
| Identifier: | 215OBS008 |
| Effectivity: | All |
| System: | Avionics Cooling System |
| Associated CAS: | None |
| System Description: | 21-54-00 |
| Schematic Diagram: | 21-54-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 20-12-10 [ Global Express ] [ G5000 ] [ Global XRS ] 21-54-00 [ Global Express ] [ G5000 ] [ Global XRS ] 34-45-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
Message Description:
The EICAS display shows IRS 1-2-3 OVHT and/or one or more IRS cooling fans do not operate.
Possible Causes:
- Inertial Reference System Cooling Fans
- Secondary-Power Distribution Assembly (SPDA) 3 (A15)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Notice To Operators (NTO): None
Flight Operation Notifications Manual (FONM): None
Quick Links:
| Operational Test of the Inertial Reference System (IRS) Cooling Fans | AMM 21-54-01-710-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Inertial Reference System (IRS) Cooling Fans | AMM 21-54-01-000-802 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Inertial Reference System (IRS) Cooling Fans | AMM 21-54-01-400-802 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Connect Electrical Power to the Aircraft | AMM 24-00-00-861-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Remove the Electrical Power from the Aircraft | AMM 24-00-00-861-802 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Opening of Non-Thermal Circuit Breakers | AMM 24-00-00-863-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Closing of Non-Thermal Circuit Breakers | AMM 24-00-00-863-802 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Electrical/Electronic Safety Precautions | AMM 24-00-00-910-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Secondary-Power Distribution Assemblies | AMM 24-62-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Secondary-Power Distribution Assemblies | AMM 24-62-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Operational Test of the Secondary-Power Distribution Assembly 3 | AMM 24-62-01-710-803 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the External Avionics-Compartment Access-Panel | AMM 52-45-11-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the External Avionics-Compartment Access-Panel | AMM 52-45-11-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Safety Precautions-Maintenance Practices | SPM 20-00-01 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Disconnect affected IRS cooling fan input power wires. Perform a 28 VDC voltage check as follows:
For the IRS fan 1 (B31):
From To Expected Result Result +28 VDC IRU 1 FAN PWR Ground 28 VDC +28 VDC IRU 1 FAN RTN Ground Continuity For the IRS fan 2 (B36):
From To Expected Result Result +28 VDC IRU 2 FAN PWR Ground 28 VDC +28 VDC IRU 2 FAN RTN Ground Continuity For the IRS fan 3 (B39):
From To Expected Result Result +28 VDC IRU 3 FAN PWR Ground 28 VDC +28 VDC IRU 3 FAN RTN Ground Continuity - If there is 28 VDC input at the fan and the ground is good, replace the IRS cooling fan.
- If voltage or grounding is missing, continue with next step.
- Disconnect associated SPDA 3 connector (A15P2, A15P3 or A15P4). Perform a continuity check as follows:
For the IRS fan 1 (B31):
From To Result +28 VDC IRU 1 FAN PWR A15P3-E For the IRS fan 2 (B36):
From To Result +28 VDC IRU 2 FAN PWR A15P3-D For the IRS fan 3 (B39):
From To Result +28 VDC IRU 3 FAN PWR A15P3-G - If there is continuity, troubleshoot the SPDA 3 power source.
- If there is no continuity, repair defective wiring as required.
- Do close out.