01/20/25
Message Overview:
Message Name:
DISAGREE / VALVE OPEN
Message Code:
B3-007681
| Associated CAS: | RAM AIR FAIL (Advisory) |
| Reporting LRU: | RAM AIR VALVE |
| System Description: | 21-53-00 - Ram-Air System |
| Schematic Diagram: | 21-53-00 - Ram Air System |
| Wiring Diagram: | 21-53-21 - Emergency Ram Air Valve |
Message Description:
The emergency RAM AIR VALVE is detected failed open by the Data Concentrator Unit or the discrete wiring to the Data Concentrator Unit is failed.
Possible Causes:
- Data Concentrator Unit (DCU) (A14)
- Ram Air Valve (RAV) (MPE40)
- Position Switch
- Bleed/Air Conditioning Panel (PL17)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None
Flight Operation Notifications Manual (FONM): None
Fault Confirmation Procedure:
- Message# = 1
- Fault Logged = AIR, TAXI
- Status = FAILED/WIRING
- Message Type = Fault Message
- {Term Definitions}
- DWDC1-22 1X 111 00 EXCT XXXX-XXXX XXXF-XXXX XXXX-XXXX 11A: !21; RAM AIR SELECTED OFF
- DWDC1-12 1X 110 00 EXCT XXXX-XXXX XXXX-XXTX XXXX-XXXX 110L: 18; RAV CLOSED
Quick Links:
| Standard Aircraft Configuration for Maintenance | AMM 12-00-00-867-803 |
| Removal of the Ram-Air Regulating-Valve | AMM 21-53-05-000-801 |
| Installation of the Ram-Air Regulating-Valve | AMM 21-53-05-400-801 |
| Deactivation of the Ram-Air Regulating Valve | AMM 21-53-05-040-801 |
| Activation of the Ram-Air Regulating Valve | AMM 21-53-05-440-801 |
| Electrical/Electronic Safety Precautions | AMM 24-00-00-910-801 |
| Electrostatic-Discharge Safety Precautions | AMM 24-00-00-910-802 |
| Connect Electrical Power to the Aircraft | AMM 24-00-00-861-801 |
| Remove the Electrical Power from the Aircraft | AMM 24-00-00-861-802 |
| Removal of the Data Concentrator Unit (DCU) | AMM 31-41-01-000-802 |
| Installation of the Data Concentrator Unit (DCU) | AMM 31-41-01-400-802 |
| Removal of the Bleed-Air Control Panel | AMM 36-11-57-000-801 |
| Installation of the Bleed-Air Control Panel | AMM 36-11-57-400-801 |
Troubleshooting Recommendations:
| LRU | Circuit Breaker | Voltage | Bus |
|---|---|---|---|
| LSPC (A37) | CB4-D6 | 28V DC | L ESS |
| RSPC (A38) | CB4-D6 | 28V DC | R MAIN |
- Check the RAV position switch.
From To Expected Results RAV Selected Open MPE40P1-1 MPE40P1-6 GND MPE40P1-5 MPE40P1-6 Open - Are the results satisfactory?
- If YES, continue with the next step.
- If NO, replace the RAM Air Valve (MPE40).
- Check wire circuit from RAV to DCU
From To Expected Results MPE40J1-1 A14FPJ1-10H Continuity MPE40J1-5 A14FPJ1-10G Continuity - Are the results satisfactory?
- If YES, continue with the next step.
- If NO, repair as required.
- Check the wire circuit from DCU (A14) to Air Conditioning/Bleed Control Panel (PL17)
From To Expected Results RAV Selected Open A14FPJ1-5J Gnd Continuity - Are the results satisfactory?
- If YES, continue with the next step.
- If NO, repair as required.
- Do AMM task AMM 21-53-21-710-802 - Operational Check of the Ram-Air Valve Circuitry.
- Are the results satisfactory?
- If YES, do close out.
- If NO, continue with the next step.
- Reseat the DCU in the rack and cycle power.
- Does the MDC Fault remain posted?
- If YES, Replace the DCU and do close out.
- If NO, continue with the next step.
- Do close out.