Fault Message:

RH AFT XFER PUMP/PRESS SW/WRG

Fault Code:

2844626PK

Associated CAS:

AFT XFER FAIL
(Caution)

AFT XFER FAULT
(Advisory)

R AFT TRNS PMP/PRES SWITCH/WRG FLT shows when the conditions that follow occur:

• The AFT XFER Switch on the Fuel Control Panel is set to ON or AUTO with the aft transfer command on
• The Right Aft Transfer-Pump pressure-indication is low
• The Electrical Management System (EMS)/AC Power Center (ACPC) has not failed

or,

• The AFT XFER Switch on the Fuel Control Panel is set to OFF or AUTO with the aft transfer command off
• The Right Aft Transfer-Pump pressure-indication is high
• The EMS/ACPC has not failed

• Right Aft Transfer Pump (B35)
• Right Aft Transfer-Pump Pressure-Switch (S23)
• Fuel Management and Quantity Gauging Computer (FMQGC) (A47)
• Fuel Control Panel (AP5)
• Associated Wiring

1. Activate the RIGHT AFT TRANSFER page on the CAIMS PMAT display as follows:

   1. Set the R WING FEED INHIBIT AUX PUMP pushbutton on the Fuel control panel to OFF.
   2. Set the R WING FEED INHIBIT PRI PUMPS pushbutton on the Fuel control panel to OFF.
   3. Set the WING XFER switch on the Fuel control panel to OFF.
   4. Set the AFT XFER switch on the Fuel control panel to AUTO.
   5. On the CAIMS PMAT, go to the RIGHT AFT TRANSFER page.
   6. Select OPEN RIGHT AFT TRANSFER VALVE.
   7. Select TURN RIGHT AFT TRANSFER PUMP ON.

2. On the Right AFT TRANSFER page, is the PUMP PRESSURE "Not Low"?

   1. If YES, go to step 7.
   2. If NO, continue with the next step.

3. Check if the fuel quantity increases in the right wing tank.

   1. If YES, go to step 10.
   2. If NO, continue with the next step.

4. Disconnect the connector A54P9 from AC Power Center. Check if there is 118 ±3 VAC at pins of connectors A54P9.

   ACPC	Expected Result	Result
   A54P9-D	118 ±3 VAC
   A54P9-E	118 ±3 VAC
   A54P9-F	118 ±3 VAC

   1. If YES, go to step 12.
   2. If NO, continue with the next step.

5. Disconnect the connectors AP5P1 and AP5P2 from FUEL PANEL. Perform a continuity check as follows:

   From	To	Result
   AP5P1-53	Ground
   AP5P2-53	Ground

   1. If there is continuity, go to step 13.
   2. If there is no continuity, continue with the next step.

6. Disconnect the connector A47DP1 from FMQGC. Perform a continuity check as follows:

   From	To	Result
   A47DP1-A13	Ground

   1. If there is continuity, go to step 14.
   2. If there is no continuity, go to step 23.

7. Keep the aft transfer valve open and on the RIGHT AFT TRANSFER page select TURN RIGHT AFT TRANSFER PUMP OFF. Check if the PUMP PRESSURE is "Low".

   1. If YES, go to step 15.
   2. If NO, continue with the next step.

8. Check if the fuel quantity increases in the right wing tank.

   1. If YES, go to step 16.
   2. If NO, continue with the next step.

9. Disconnect the connector S23P1 from RIGHT AFT TRANSFER PUMP PRESSURE SW. Check if there is an open circuit to ground and a short-circuit to ground as follows:

   From	To	Expected Result	Result
   S23P1-G	Ground	Open
   S23P1-A	Ground	Continuity

   1. If the results are as described in the table above, go to step 20.
   2. If the results are not as described in the table above, go to step 21.

10. Check if there is a short-circuit to ground and an open circuit to ground as follows:

    From	To	Expected Result	Result
    S23P1-G	Ground	Continuity
    S23P1-A	Ground	Open

    1. If the results are not as described in the table above, go to step 21.
    2. If the results are as described in the table above, continue with the next step.

11. Check if there is a short-circuit to ground and an open circuit to ground as follows:

    From	To	Expected Result	Result
    A47DP1-A11	Ground	Continuity
    A47DP1-B11	Ground	Open

    1. If the results are as described in the table above, go to step 23.
    2. If the results are not as described in the table above, repair or replace the defective wiring as required and do close out.

12. Disconnect the connector B35P1 from RIGHT AFT AUX TRANSFER PUMP. Check if there is 118 ±3 VAC at pins of connector B35P1 as follows:

    Right Aft Aux Transfer Pump	Expected Result	Result
    B35P1-A	118 ±3 VAC
    B35P1-B	118 ±3 VAC
    B35P1-C	118 ±3 VAC

    1. If the results are as described in the table above, replace the right aft transfer pump and do close out.
    2. If the results are not as described in the table above, repair or replace the defective wiring as required and do close out.

13. Disconnect the connectors A94P2 from EMS CDU 1 and A91P2 from EMS CDU 2. Perform a continuity check as follows:

    From	To	Result
    A94P2-42	Ground
    A91P2-42	Ground

    1. If there is continuity, perform a troubleshooting for the EMS/ACPC.
    2. If there is no continuity, repair or replace the defective wiring as required and do close out.

14. Perform a continuity check as follows:

    From	To	Result
    AP5P2-66	Ground

    1. If there is continuity, go to step 22.
    2. If there is no continuity, repair or replace the defective wiring as required and do close out.

15. Perform a continuity check as follows:

    From	To	Result
    A47DP1-C13	AP5P2-36
    A47DP1-D13	AP5P2-39
    A47DP1-E13	AP5P2-46

    1. If the fault is still present AND there is continuity, replace the FUEL control panel and do close out.
    2. If there is no continuity, repair or replace the defective wiring as required and do close out.

16. Perform a continuity check as follows:

    From	To	Result
    A94P2-42	Ground
    A91P2-42	Ground

    1. If there is no continuity, perform a troubleshooting for the EMS/ACPC.
    2. If there is continuity, continue with the next step.

17. Perform a continuity check as follows:

    From	To	Result
    A47DP1-A13	Ground

    1. If there is continuity, go to step 23.
    2. If there is no continuity, continue with the next step.

18. Perform a continuity check between AP5P2-66 and ground.

    From	To	Result
    AP5P2-66	Ground

    1. If there is continuity, repair or replace the defective wiring as required and do close out.
    2. If there is no continuity, continue with the next step.

19. Perform a continuity check as follows:

    From	To	Result
    AP5P1-53	Ground
    AP5P2-53	Ground

    1. If there is continuity, go to step 22.
    2. If there is no continuity, repair or replace the defective wiring as required and do close out.

20. Check if there is a short-circuit to ground and an open circuit to ground as follows:

    From	To	Expected Result	Result
    A47DP1-B11	Ground	Continuity
    A47DP1-A11	Ground	Open

    1. If the results are as described in the table above, go to step 23.
    2. If the results are not as described in the table above, repair or replace the defective wiring as required and do close out.

21. Replace the right aft transfer-pump pressure-switch.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

22. Replace the Fuel Control Panel.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

23. Replace FMQGC.

    1. If system checks are good, do close out.
    2. If fault remains, continue with next step.

24. Do close out.