02/24/21
Message Overview:
Message Name:
NO L RIU CHAN B OUTPUT
Message Code:
B3-398868
Associated CAS:
| Reporting LRU: | RIU 1 |
| System Description: | 23-00-00 |
| Schematic Diagram: | None |
| Wiring Diagram: | None |
Message Description:
LB-RIU bus data not received at R PFD and 2-OF (L-PFD, L-CDU, or DCU) while LA-RIU bus data is received at L-IOC.
Possible Causes:
- LB-Radio Interface Unit (RIU) 1 (A17)
- Associated Wiring
Troubleshooting Tips:
Advisory Wire/Service Bulletin: None
Forum Articles/Infoservice/Newsletter: None
Fault Confirmation Procedure:
- Message# = 4
- Comp Id = A017
- Fault Logged = AIR,TAXI
- Status = OFF/NO OUTPUT
- {Term Definitions}
- RIU1-1 1X 350 01 ABSN XXXX-XXXX XXXX-XXXX XXXX-XXXX 350: (A) NO IOC 1X IN;
- PFD2-35 2X 351 NA EXCT XXXX-XTXX XXXX-XXXX XXXX-XXXX 351: 27;NO LB-RIU-9 INPUT
- PFD1-35 1X 351 NA EXCT XXXX-XTXX XXXX-XXXX XXXX-XXXX 351: 27;NO LB-RIU-6 INPUT
- CDU1-7 1X 350 01 EXCT XXXX-XXXX XXXX-XXXX TXXX-XXXX 350: 16;NO LB-RIU-6 I
- DCU1-28 1X 357 01 EXCT XXXX-XXXX TXXX-XXXX XXXX-XXXX 357: 24;LB-RIU-6 BUS INOP
Quick Links:
| Removal of the Radio Interface Unit (RIU) | AMM 23-51-21-000-801 |
| Installation of the Radio Interface Unit (RIU) | AMM 23-51-21-400-801 |
| Standard Practices - Replace Wiring | SPM 20-12-00-02 |
| Standard Practices - Wire Repair | SPM 20-12-10-02 |
Troubleshooting Recommendations:
- Suspect LB- RIU Power or failed LB RIU outputs or wiring.
- For aircraft pre SB 350-23-004, you may swap RIU 1 with RIU 2 to see if fault will follow.
- Do close out.