06/30/21
Message Overview:
Message Name:
CBW MECHANICALLY FAILED CLOSED WITH AMBER INTERMEDIATE POSITION INDICATION ON EICAS
| Message Code: | 301OBS004 |
| Effectivity: | All |
| System: | Wing Cross Bleed Valve |
| System Description: | 36-11-00 |
| Schematic Diagram: | 36-11-00 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wiring Diagram: | 30-11-03 [ Global Express ] [ G5000 ] [ Global XRS ] |
Message Description:
There is a mechanical failure of the Wing Cross Bleed Valve (or Wing Anti-Ice (WAI) Isolation Valve) (in the closed position) and the Engine Indication and Crew Alerting System (EICAS) shows an intermediate (not fully closed or not fully open) position in amber.
Possible Causes:
- Wing Cross Bleed Valve (CBW) (L33)
- Left Bleed Management Controller (A69)
- Right Bleed Management Controller (A70)
- Data Acquisition Unit (DAU) 3 (A30)
- Junction Box (JB3)/PCB4
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter:
- When CBW is fully closed, CBW L33P1-5 provides a ground signal (CBW L33 pins 6 and 5 are shorted) to BMCs
- When CBW is fully open, CBW L33P1-1 provides a ground signal (CBW L33 pins 6 and 1 are shorted) to BMCs
- CBW L33P1-6 is connected to Ground Stud GS390 to provide the ground signal for fully closed/fully open to BMCs
Quick Links:
| Removal of the Junction Box JB3 | AMM 24-00-01-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Junction Box JB3 | AMM 24-00-01-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Junction Box JB3 Circuit-Cards |
AMM 24-00-02-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Junction Box JB3 Circuit-Cards |
AMM 24-00-02-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Operational Test of the WING XBLEED System |
AMM 30-11-00-710-802 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Wing Cross-Bleed Valve | AMM 30-11-09-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Wing Cross-Bleed Valve | AMM 30-11-09-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Removal of the Bleed Management Controller | AMM 36-11-33-000-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Installation of the Bleed Management Controller | AMM 36-11-33-400-801 [ Global Express ] [ G5000 ] [ Global XRS ] |
| Wire Repair - Maintenance Practices - ALL | SPM 20-12-10-02 [ Global Express ] [ G5000 ] [ Global XRS ] |
Troubleshooting Recommendations:
- Manually open CBW.
- If CBW cannot be opened, go to step 3.
- If CBW open and EICAS show fully open, continue with next step.
- Perform a CBW operational test.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace CBW.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Perform wiring checks between BMC 1, BMC 2, JB3, CBW, DAU 3 and GS390.
- If wiring checks are not good, repair defective wiring as required and do close out.
- If wiring checks are good, continue with next step.
NOTE: Remove all interface components for short test.
- Swap DAU 3 with DAU 1.
- If system checks are good, replace DAU 3 and do close out.
- If fault remains, continue with next step.
- Replace BMC 1.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace BMC 2.
- If system checks are good, do close out.
- If fault remains, continue with next step.
- Replace PCB4/JB3.
- Do close out.