R AUX BUS FAIL
(Advisory)

The cyan 'R AUX BUS FAIL' advisory CAS message indicates the affected auxiliary bus is not powered with a power source available. This CAS will be posted when one or more associated relay(s) is (are) not operating properly.

Each DC Power Control Center has a 400 Amp Auxiliary power contactor (Relay) that is automatically controlled by the power cent

• Electrical System Component(s)
• Associated Wiring

Advisory Wire/Service Bulletin:

• AW300-24-0162 - Service Bulletin 100-24-20 - DC Power Center (DCPC) System - Inspection and Replacement of Internal Fuses in the L/H and R/H DC Power Center (DCPC).
• SB100-24-20 - Special Check/Modification - DC Power Center (DCPC) System - Inspection and Replacement of Internal Fuses in the L/H and R/H DC Power Center (DCPC).

Forum Articles/Infoservice/Newsletter: None

None

1. Interrogate the MDC as follows:

   1. On the cursor control panel, ensure the toggle switch is to the right and select Anti-Ice, ECS and Fuel buttons simultaneously. The MDC main menu should now be displayed on Display Unit #3.
   2. Using the joystick, select Current Faults (if the fault is active) or Aircraft History to research stored faults. From Aircraft History you can then select Fault Message History and locate the fault. Going into advanced diagnostics will provide an equation ID for the fault identified.
   3. Select the MDC fault or equation from the drop down below to provide additional information to assist in troubleshooting.
      Select an MDC Fault Code/Message:B3-007679 - FAULT [R AUX BUS CNTOR]B3-007680 - FUSE BLOWN [R AUX/MN BUS FUSE]B3-269343 - FUSE BLOWN [R AUX BUS FUSE]