Message Name:

AFT REFUEL/DEFUEL SOV/WRG

Message Code:

284463CPK

Associated CAS:

AFT RD VALVE OPEN
(Advisory)

AFT REFUEL/DEFUEL VALVE/WRG FAULT shows when the conditions that follow occur:

• The Aft Refuel/Defuel Valve is commanded to close
• The open feedback-signal of the Aft Refuel/Defuel Valve is true or the close feedback-signal is false

OR,

• The Aft Refuel/Defuel Valve is commanded to open
• The open feedback-signal of the Aft Refuel/Defuel Valve is false or the close feedback-signal is true

• Fuel Management and Quantity Gauging Computer (FMQGC) (A47)
• Aft Refuel Shut-off Valve (L4)
• Junction Box (JB6)
• Junction Box (JB6)/PCB1
• Junction Box (JB6)/PCB2
• Junction Box (JB6)/PCB3
• Auxiliary Power Unit (APU) Start Contactor Assembly (ASCA) (A48)
• Auxiliary Power Unit (APU) Main Battery
• Associated Wiring

Advisory Wire/Service Bulletin: None

Full Throttle Blog/Forum Articles/Infoservice/Newsletter: None

Flight Operation Notifications Manual (FONM): None

1. Disconnect the Aft Refuel/Defuel SOV connector L4P1. Perform the following:

   • Apply power to the aircraft
   • Set the MASTER switch on the REFUEL/DEFUEL control panel to "ON"
   • Set the REFUEL/AUTO REFUEL DEFUEL switch to "REFUEL"
   • Set the MANUAL/AFT switch to "CLOSE"

2. On Aft R/D SOV connector L4P1, perform a voltage and ground check as follows:

   From	To	Expected Result	Result
   L4P1-B	Ground	28 +/-2 VDC
   L4P1-A	Ground	Continuity

   1. If all checks are good, go to step 5.
   2. If there is no continuity on L4P1-A, repair defective wiring as required and do close out.
   3. If there is no voltage on L4P1-B, continue with next step.

3. Access JB6 test points. Perform a voltage and ground check as follows:

   From	To	Expected Result	Result
   JB6 PCB1 TP-92	Ground	28 +/-2 VDC
   JB6 PCB1 TP-19	Ground	Open

   1. If there is continuity on TP-19, investigate wiring and go to step 7.
   2. If there no voltage on TP-92, use System Schematic 28-23-00 to investigate the power source.
   3. If all checks are good, continue with next step.

4. Perform a voltage check as follows:

   From	To	Expected Result	Result
   JB6 PCB2 TP-36	Ground	28 +/-2 VDC
   JB6 PCB2 TP-35	Ground	28 +/-2 VDC
   JB6 PCB3 TP-37	Ground	28 +/-2 VDC
   JB6 PCB3 TP-36	Ground	28 +/-2 VDC

   1. If all checks are good, investigate wiring between the Aft R/D SOV and JB6 and do close out.
   2. If PCB3 has no voltage, replace PCB3 and do close out.
   3. If only PCB2 has no voltage, replace PCB2 and do close out.

5. Set the MANUAL/AFT switch to "OPEN". On Aft R/D SOV connector L4P1, perform a voltage check as follows:

   From	To	Expected Result	Result
   L4P1-D	Ground	28 +/-2 VDC

   1. If there is voltage, replace the Aft R/D SOV and do close out.
   2. If there is no voltage, continue with next step.

6. Access JB6 test points. Perform a voltage and ground check as follows:

   From	To	Expected Result	Result
   JB6 PCB1 TP-92	Ground	28 +/-2 VDC
   JB6 PCB1 TP-19	Ground	Continuity

   1. If all checks are good, replace JB6 PCB1 and do close out.
   2. If there no voltage on TP-92, use System Schematic 28-23-00 to investigate the power source.
   3. If there is no continuity on TP-19, investigate wiring and continue with next step.

7. Replace the FMQGC.
8. Do close out.