W DOC AIRBUS | TSM A320F

Center Tank Autofeed System (Sequence/Distribution) Fault - The Fuel Has Not Been Used In The Correct Sequence During An Aircraft Flight

TASK 28-21-00-810-823-A
Center Tank Autofeed System (Sequence/Distribution) Fault - The Fuel Has Not Been Used In The Correct Sequence During An Aircraft Flight

WARNING: OBEY THE FUEL SAFETY PROCEDURES.
WARNING: WHEN YOU DO WORK ON THE FUEL SYSTEM WIRING, YOU MUST USE TEST EQUIPMENT THAT IS APPROVED (REFER TO INTERNATIONAL OR NATIONAL SPECIFICATIONS FOR INTRINSICALLY SAFE TEST EQUIPMENT: EN50020, UL913 OR EQUIVALENT). TEST EQUIPMENT THAT IS NOT APPROVED CAN CAUSE FIRE OR AN EXPLOSION.
1. Possible Causes
  • Fuel Quantity Indication Computer (FQIC) 3QT.
  • C LO LEVEL SENSOR 21QJ
  • C LO LEVEL SENSOR 22QJ
  • L(R) FULL LEVEL SENSOR 23QJ1(2)
  • L(R) UNDERFULL LEVEL SENSOR 24QJ1(2)
  • L(R) UNDERFULL LEVEL SENSOR 25QJ1(2)
  • L(R) UNDERFULL LEVEL SENSOR 26QJ1(2)
  • L(R) FULL LEVEL SENSOR 27QJ1(2)
  • Internal Fuel Leak
  • SLAT/FLAP CONTR.COMP. [21CV]
  • SLAT/FLAP CONTR.COMP. [22CV]
  • RELAY-L WING TK REFUEL VALVE CONTROL [15QU]
  • RELAY-R WING TK REFUEL VALVE CONTROL [16QU]
  • RELAY-CTR TK REFUEL VALVE CTL (17QU).
  • aircraft wiring
  • FLSCU-1 [7QJ]
  • RELAY-CTR TK AUTO CONTROL, PUMP 1 [41QA]
  • RELAY-CTR TK PUMPS 1 CTL [51QA]
  • RELAY-CTR TK LOW LEVEL, N#Auml# 1 [45QA]
  • RELAY-CTR TANK PUMP 1, LATCHED OFF (67QA)
  • FLSCU-2 [9QJ]
  • RELAY-CTR TK AUTO CONTROL, PUMP 2 [42QA]
  • RELAY-CTR TK PUMPS 2 CTL [52QA]
  • RELAY-CTR TK LOW LEVEL, N#Auml# 2 [46QA]
  • RELAY-CTR TANK PUMP 2, LATCHED OFF (68QA)
  • SEQUENCE VALVE
  • PUMP-FUEL NO 1, CTR TK [37QA]
  • PUMP-FUEL NO 2, CTR TK [38QA]
  • P/BSW-CTR TK/MODE SEL [48QA]
  • RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU]
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
TSM TASK 28-21-00-810-816-A
Fuel Pumps - Center Tank Autofeed Warning and/or FAULT Legend Failure
TSM TASK 28-21-00-810-825-A
Internal Fuel Leak Which Causes a Fuel Imbalance or a Discharge From a NACA Vent During Taxi or Flight
TSM TASK 28-42-00-810-801-A
Fuel Quantity Indication Computer (FQIC) 3QT
AMM 12-11-28-650-003
Pressure Refuel with Automatic Control
ESPM 2052210
ESPM 2052220
ESPM 2053210
AMM 27-51-34-000-001
Removal of the SFCC
AMM 27-51-34-400-001
Installation of the SFCC
AMM 27-80-00-866-005
Retracting the Slats on the Ground
AMM 28-21-00-710-007
Operational Test of the Main Fuel-Pump System with Fuel Flow by Transfer
AMM 28-21-00-720-001
Functional Test of the Center-Tank Fuel Control
ASM 282104
AMM 28-21-45-000-001
Removal of the Sequence Valve
AMM 28-21-45-400-003
Installation of the Sequence Valve
AMM 28-21-51-000-002
Removal of the Fuel Pumps
AMM 28-21-51-400-002
Installation of the Fuel Pumps
AMM 28-25-00-650-001
Pressure Defuel
AMM 28-25-00-869-001
Fuel Transfer
AMM 28-46-00-740-001
Functional (BITE) Test
AMM 28-46-34-000-001
Removal of the Fuel-Level Sensing Control-Unit (FLSCU)
AMM 28-46-34-400-001
Installation of the Fuel-Level Sensing Control-Unit (FLSCU)
AMM 31-60-00-860-001
EIS Start Procedure
3. Fault Confirmation
Subtask 28-21-00-710-073-B ** ON A/C NOT FOR ALL
A. Introduction

The ECAM warning, FUEL - AUTO FEED FAULT is a configuration (fuel load distribution) warning.
The FWC (Ref. ESLD 1.28.400) supplies the ECAM warning.

This warning function is activated simultaneously with the FAULT legend on the P/BSW-CTR TK/MODE SEL/AUTO (48QA).
The FAULT is only given when the P/BSW is in the AUTO position ASM 282104.

These indications are given when:
  • the distribution of the fuel load is not correct during a refuel
  • the fuel is not used in the correct sequence.

The warning is activated if (for 60 seconds) the fuel distribution is as follows:
  • the left wing tank is less than 5000 kg (11000 lb) AND the center tank is more than 250 kg (550 lb)
  • the right wing tank is less than 5000 kg (11000 lb) AND the center tank is more than 250 kg (550 lb).

The warning is reset immediately when the fuel distribution conditions no longer exist.

The comparison logic which activates and resets this warning is contained in the FQIC (3QT).
The FQIC warning/FAULT logic output is inhibited during automatic pressure refuel.

The FQIC warning/FAULT logic output is transmitted on:
  • two ARINC bus lines to the FWC (ECAM)
  • two discrete signal lines OR gated together to the P/BSW-CTR TK/MODE SEL/AUTO (48QA), FAULT legend.

If the signals for the pump state and the aircraft configuration are different, there will be an AUTO FEED warning.
  • After an engine is started and the slats are extended the centre tank pumps will run for 2 minutes. If the pumps do not stop after 2 minutes there will be a signal fault.
  • After take off, the slats are retracted and the centre tank pumps will start. If the pumps do not start, there will be a signal fault.

    This procedure is only applicable when the fuel has not been used in the correct sequence during an aircraft flight.
NOTE: The correct sequence for the fuel to be used (the tanks to empty) is as follows:
1 - the center tank
2 - the wing-tank inner-cell down to 750 kg (1660 lb)
3 - the wing-tank outer-cell fuel transfers to inner-tank.
   (1) Get as much data as possible about the fault.
Example, if possible:
  • examine the aircraft log for more references to this fault
  • investigate the fuel configuration at the time of the original/repeat fault
  • find out if the center tank pump indications were correct at the time of the fault.
     (a) If:

  • no more data is available, do Para. 3.B.

  • more data is available, do step (2).
   (2) Compare this with the fuel configuration that causes the warning/FAULT to be given.
   (3) On the ECAM (FUEL system page), do a check of the related fuel tank FQI indications.
  • If the indications are not correct, do the (Ref. TSM TASK 28-42-00-810-801) Fuel Quantity Indication Computer (FQIC) 3QT. procedure.
  • If the indications are correct, do step (4).
   (4) On the ECAM (FUEL system page), do a check of the center-tank pump indications.
  • If the indications are not correct, do Para. 3.B.
  • If the indications are correct, do Para. 3.C.
Subtask 28-21-00-710-093-B ** ON A/C NOT FOR ALL
B. Test One
NOTE: This test is to make sure that the FLSS channels that are used to control some of the center-tank fuel-pump auto-control circuits are serviceable.
   (1) Do the Functional (BITE) test of the FLSS AMM 28-46-00-740-001.
   (2) Examine the FLSS STATUS page for one or more of the messages that follow:
  • FLSCU1(2) 7QJ(9QJ)
  • C LO LEVEL SENSOR 21QJ
  • C LO LEVEL SENSOR 22QJ
  • L(R) FULL LEVEL SENSOR 23QJ1(2)
  • L(R) UNDERFULL LEVEL SENSOR 24QJ1(2)
  • L(R) UNDERFULL LEVEL SENSOR 25QJ1(2)
  • L(R) UNDERFULL LEVEL SENSOR 26QJ1(2)
  • L(R) FULL LEVEL SENSOR 27QJ1(2).
     (a) If:

  • none of the messages are shown, go to Para. 3.C.

  • one or more of the messages is/are shown, go to step (3).
   (3) Troubleshoot the LRU(s) that are shown on the FLSS STATUS page before you start the next paragraph.
     (a) Refer to Start Troubleshooting, CFDS for the related TSM procedure.
     (b) If none of the messages (given in step (2)) are reported on the FLSS STATUS page on the completion of a Function (BITE) test of the FLSS, do Para. 3.C.
Subtask 28-21-00-710-094-B ** ON A/C NOT FOR ALL
C. Test Two
NOTE: This test is to make sure that each one of the six fuel-pumps is serviceable. To do this you monitor the change in fuel-tank FQIs which is the result of a fuel transfer. The fuel-pump motor and impellor cause the fuel transfer. A broken or damaged impellor can reduce the fuel output of the applicable pump assembly.

The test also makes sure that the center-tank fuel-pumps are serviceable in the manual mode of operation before you start troubleshooting the auto-mode of operation in Para. 3.D.
   (1) Do the Operational Test of the Main Fuel Pump System with Fuel Flow by Transfer AMM 28-21-00-710-007 as follows:
     (a) During the test for for each fuel tank group (Left/Right/Center) operate each fuel-pump (in turn) as follows:
       1 Set the (L/R/C) pump 1 on.
       2 Monitor the FQI values to see that the fuel has moved from tank to tank.
       3 Set the (L/R/C) pump 1 off.
       4 Set the (L/R/C) pump 2 on.
       5 Monitor the FQI values to see that the fuel has moved from tank to tank.
       6 Set the (L/R/C) pump 2 off.
     (b) If a Manual Mode fuel pump fault:

  • is not found, do Para. 3.D.

  • is found, do step (2).
   (2) Troubleshoot all the fault(s) before you start the next paragraph.
     (a) Refer to Start Troubleshooting, ECAM/Local/System Page for the related TSM procedure.
     (b) When the fuel-pumps operate as specified in the manual mode do Para. 3.D.
Subtask 28-21-00-710-095-B ** ON A/C NOT FOR ALL
D. Test Three
NOTE: This test is to make sure that the center-tank fuel-pump auto-control circuits give the correct output for all the different inputs.

The test also puts the center-tank fuel-pump system in the correct condition for troubleshooting in Para. 4.
   (1) Do the Functional Test of the Center Tank Fuel Control AMM 28-21-00-720-001.
     (a) If the Fuel Pump Auto Feed system:

  • operates as specified, do the TSM procedure for an Internal Fuel Leak Which Causes a Fuel Imbalance or a Discharge From a NACA Vent During Taxi or Flight (Ref. TSM TASK 28-21-00-810-825)

  • does not operate as specified (or if an in-flight malfunction has occurred again), do Para. 4.
     (b) If an ECAM warning or FAULT legend failure is found, do the TSM procedure 'Fuel Pumps - Center Tank Autofeed Warning and/or FAULT Legend Failure' (Ref. TSM TASK 28-21-00-810-816).
4. Fault Isolation
Subtask 28-21-00-810-073-C ** ON A/C NOT FOR ALL
A. Procedure
   (1) Set the Electronic Centralized Aircraft Monitoring (ECAM) system to on AMM 31-60-00-860-001.
   (2) On the ECAM control panel, push (in) the FUEL P/BSW.
   (3) Make sure that the FUEL page shows on the ECAM lower Display Unit (DU).
   (4) Make sure that the fuel configuration (load) is as follows:
  • left wing tank 5100 kg (11244 lb)
  • right wing tank 5100 kg (11244 lb)
  • center tank more than 250 kg (550 lb).
     (a) If necessary, refuel AMM 12-11-28-650-003, defuel AMM 28-25-00-650-001 or transfer fuel AMM 28-25-00-869-001 to obtain the fuel levels given.
   (5) Make sure that the slats are fully retracted AMM 27-80-00-866-005.
   (6) Push (in) the P/BSW-CTR TK/MODE SEL/AUTO (48QA) (set to auto).
   (7) Push (in) all the fuel pump P/BSWs (set to on).
   (8) Examine the FUEL page on the ECAM lower DU.
     (a) If:

  • the center tank pumps 1 and 2 are shown off, do step (9)

  • the center tank (left side) pump 1 is shown off, do step (10)

  • the center tank (right side) pump 2 is shown off, do step (11)

  • the center tank pumps are shown correct, do step (12).
   (9) The center tank pumps 1 and 2 are shown off.
     (a) Temporarily remove the SFCC No 1 (21CV) and 2 (22CV) in turn from their racks AMM 27-51-34-000-001.
       1 Examine the FUEL page on the ECAM lower DU.
       2 If the center tank pumps 1 and 2 operate correctly:
       3 If the fault continues:
         a Do a check of and replace, if necessary ASM 282104:
  • the RELAY-L WING TK REFUEL VALVE CONTROL [15QU]
  • the RELAY-R WING TK REFUEL VALVE CONTROL [16QU]
  • the RELAY-CTR TK REFUEL VALVE CTL (17QU).
         b Do a wiring check of the aircraft wiring (> 16 degrees signal(ground) wire) ASM 282104 between:
  • the SFCC-1 rack connector 21CV-AE, pin 10H and the RELAY-CTR TK PUMP 1 CTL (51QA), terminal A3
  • the SFCC-1 rack connector 21CV-AE, pin 10H and the RELAY-CTR TK PUMP 2 CTL (52QA), terminal A3
  • the SFCC-2 rack connector 22CV-AE, pin 10H and the RELAY-CTR TK PUMP 2 CTL (52QA), terminal A3
  • the SFCC-2 rack connector 22CV-AE, pin 10H and the RELAY-CTR TK PUMP 1 CTL (51QA), terminal A3.
NOTE: A wiring check means that you test the wire(s) specified as follows:

These checks are necessary to find a possible short-circuit to ground in the center-tank fuel-pump auto-control circuits. A short-circuit (as described) can cause the applicable fuel-pump 115VAC (three-phase electrical supply) to be held off.
         c Repair all the unserviceable wiring and connectors ESPM 2053210.
         d Do a wiring check of the aircraft wiring (latch ground wire) ASM 282104 between:
  • RELAY-CTR TK REFUEL VALVE CTL (17QU), terminal B3 and the RELAY-CTR TK PUMP 1, LATCHED OFF (67QA), terminal 2
  • RELAY-CTR TK REFUEL VALVE CTL (17QU), terminal B3 and the RELAY-CTR TK PUMP 2, LATCHED OFF (68QA), terminal 2
         e Repair all the unserviceable wiring and connectors ESPM 2053210.
         f Do the test given in Para. 3.D.
     (b) If the fault continues:
  • Do step (13).
   (10) The center tank (left side) pump 1 is shown off.
     (a) Temporarily remove the FLSCU-1 (7QJ) from its rack AMM 28-46-34-000-001.
       1 Examine the FUEL page on the ECAM lower DU.
       2 If the center tank pump 1:
         a Operates correctly and shows on:
         b Shows off:
       3 If the fault continues:
         a Do a check of ASM 282104 and replace, if necessary, the:
  • RELAY-CTR TK AUTO CONTROL, PUMP 1 [41QA]
  • RELAY-CTR TK PUMPS 1 CTL [51QA]
  • RELAY-CTR TK LOW LEVEL, N#Auml# 1 [45QA]
  • RELAY-CTR TANK PUMP 1, LATCHED OFF (67QA).
         b Do a wiring check of the aircraft wiring ASM 282104 between:
  • the FLSCU-1 rack connector 7QJ-AA, pin 11D and the RELAY-CTR TK PUMP 1 CTL (51QA), terminal A3 (logic 2/recirc. off (ground) wire)
  • the FLSCU-1 rack connector 7QJ-AA, pin 8B and the RELAY-CTR TK LO LVL, No 1 (45QA), terminal X2 (CTR TK low level 1 off (ground) wire)
  • the RELAY (45QA) terminal X2 and the RELAY (67QA), terminal A (CTR TK low level 1 off latch (ground) wire)
  • the RELAY (51QA) terminal A2 and the RELAY (41QA), terminal Z (CTR TK Pump 1 - Auto off (ground) wire)
  • the RELAY (67QA) terminal 4 and the RELAY (41QA), terminal Z (CTR TK Pump 1 - Auto off (ground) wire)
  • the RELAY (67QA) terminal 2 and the RELAY-CTR TK REFUEL VALVE CTL (17QU), terminal B3 (CTR TK low level 1 off latch (ground) wire).
         c Repair all the unserviceable wiring and connectors ESPM 2053210.
         d Do the test given in Para. 3.D.
     (b) If the fault continues:
  • Do step (13).
   (11) The center tank (right side) pump 2 is shown off.
     (a) Temporarily remove the FLSCU-2 (9QJ) from its rack AMM 28-46-34-000-001.
       1 Examine the FUEL page on the ECAM lower DU.
       2 If the center tank pump 2:
         a Operates correctly and shows on:
         b Shows off:
       3 If the fault continues:
         a Do a check of ASM 282104 and replace, if necessary, the:
  • RELAY-CTR TK AUTO CONTROL, PUMP 2 [42QA]
  • RELAY-CTR TK PUMPS 2 CTL [52QA]
  • RELAY-CTR TK LOW LEVEL, N#Auml# 2 [46QA]
  • RELAY-CTR TANK PUMP 2, LATCHED OFF (68QA).
         b Do a wiring check of the aircraft wiring ASM 282104 between:
  • the FLSCU-2 rack connector 9QJ-AA, pin 11D and the RELAY-CTR TK PUMP 2 CTL (52QA), terminal A3 (logic 2/recirc. off (ground) wire)
  • the FLSCU-2 rack connector 9QJ-AA, pin 8B and the RELAY-CTR TK LO LVL, No 2 (46QA), terminal X2 (CTR TK low level 2 off (ground) wire)
  • the RELAY (46QA) terminal X2 and the RELAY (68QA), terminal A (CTR TK low level 2 off latch (ground) wire)
  • the RELAY (52QA) terminal A2 and the RELAY (42QA), terminal Z (CTR TK Pump 2 - Auto off (ground) wire)
  • the RELAY (68QA) terminal 4 and the RELAY (42QA), terminal Z (CTR TK Pump 2 - Auto off (ground) wire)
  • the RELAY (68QA) terminal 2 and the RELAY-CTR TK REFUEL VALVE CTL (17QU), terminal B3 (CTR TK low level 2 off latch (ground) wire).
         c Repair all the unserviceable wiring and connectors ESPM 2053210.
         d Do the test given in Para. 3.D.
     (b) If the fault continues:
  • Do step (13).
   (12) If (the center-tank fuel-pump indications are correct) but the fault continues, do tests of the fuel output pressure from each of the three fuel pumps (on the applicable side of the aircraft) as follows:
     (a) Wing Tank Pumps
       1 Go to the AMM TASK, Installation of the Sequence Valve AMM 28-21-45-400-003.
       2 Do Para. 4.D. (Preparation for Test) thru Para. 4.G (Test of the Sequence Valve), on the L(R) wing tank fuel pump, No. 1.
       3 Make sure that the fuel pressure is as specified AMM 28-21-45-400-003.
NOTE: The fuel pressure given in the test is without a fuel transfer.
NOTE: The fuel output pressure of the wing tank fuel pumps is less than that of the center tank fuel pumps.
This is because the sequence valves act as relief valves:
  • reducing the fuel output pressure to allow the center tank fuel to be used first
  • returning their fuel output to the related wing tanks.
       4 If the fuel pressure is more than that specified:
       5 Do steps 1_ thru 4_ again on the L(R) wing tank fuel pump, No. 2.
     (b) Center Tank Pump
       1 Go to the AMM TASK, Installation of the Sequence Valve AMM 28-21-45-400-003.
NOTE: Sequence valves are not fitted to the center tank pumps but the fuel pump pressure can be tested using the same procedure.
The fuel output pressure of the center tank fuel pumps is more than that of the wing tank fuel pumps.
       2 Do Para. 4.D. (Preparation for Test) thru Para. 4.G. (Test of the Sequence Valve) on the center tank fuel pump, No. 1(2).
       3 Make sure that the fuel pressure for the center tank pumps is more than approximately 2.76 bar (40.0 psi).
NOTE: The fuel pressure given here for this test is without a fuel transfer.
       4 If the fuel pressure is less than that specified:
     (c) If the fault continues:
       1 Do more troubleshooting to find (investigate) the reason for the fuel-pump out of specification (high or low) fuel pressure and make sure that:
  • the fuel-pump pick up strainer and input pipe is clear
  • the fuel-pump/canister outlet pipe work is not blocked, damaged and/or leaking.
       2 Replace all the unserviceable fuel pipes and strainers.
       3 Do the test given in Para. 3.D.
     (d) If the fault continues:
  • Do step (13).
   (13) Replace the P/BSW-CTR TK/MODE SEL [48QA] .
     (a) Do the tests given in Para. 3. D.
Subtask 28-21-00-810-073-E ** ON A/C NOT FOR ALL
A. Procedure
   (1) Set the Electronic Centralized Aircraft Monitoring (ECAM) system to on AMM 31-60-00-860-001.
   (2) On the ECAM control panel, push (in) the FUEL P/BSW.
   (3) Make sure that the FUEL page shows on the ECAM lower Display Unit (DU).
   (4) Make sure that the fuel configuration (load) is as follows:
  • left wing tank 5100 kg (11244 lb)
  • right wing tank 5100 kg (11244 lb)
  • center tank more than 250 kg (550 lb).
     (a) If necessary, refuel AMM 12-11-28-650-003, defuel AMM 28-25-00-650-001 or transfer fuel AMM 28-25-00-869-001 to obtain the fuel levels given.
   (5) Make sure that the slats are fully retracted AMM 27-80-00-866-005.
   (6) Push (in) the P/BSW-CTR TK/MODE SEL/AUTO (48QA) (set to auto).
   (7) Push (in) all the fuel pump P/BSWs (set to on).
   (8) Examine the FUEL page on the ECAM lower DU.
     (a) If:

  • the center tank pumps 1 and 2 are shown off, do step (9)

  • the center tank (left side) pump 1 is shown off, do step (10)

  • the center tank (right side) pump 2 is shown off, do step (11)

  • the center tank pumps are shown correct, do step (12).
   (9) The center tank pumps 1 and 2 are shown off.
     (a) Temporarily remove the SFCC No 1 (21CV) and 2 (22CV) in turn from their racks AMM 27-51-34-000-001.
       1 Examine the FUEL page on the ECAM lower DU.
       2 If the center tank pumps 1 and 2 operate correctly:
       3 If the fault continues:
         a Do a check of and replace, if necessary ASM 282104:
  • the RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
         b Do a wiring check of the aircraft wiring (> 16 degrees signal(ground) wire) ASM 282104 between:
  • the SFCC-1 rack connector 21CV-AE, pin 10H and the RELAY-CTR TK PUMP 1 CTL (51QA), terminal A3
  • the SFCC-1 rack connector 21CV-AE, pin 10H and the RELAY-CTR TK PUMP 2 CTL (52QA), terminal A3
  • the SFCC-2 rack connector 22CV-AE, pin 10H and the RELAY-CTR TK PUMP 2 CTL (52QA), terminal A3
  • the SFCC-2 rack connector 22CV-AE, pin 10H and the RELAY-CTR TK PUMP 1 CTL (51QA), terminal A3.
NOTE: A wiring check means that you test the wire(s) specified as follows:

These checks are necessary to find a possible short-circuit to ground in the center-tank fuel-pump auto-control circuits. A short-circuit (as described) can cause the applicable fuel-pump 115VAC (three-phase electrical supply) to be held off.
         c Repair all the unserviceable wiring and connectors ESPM 2053210.
         d Do the test given in Para. 3.D.
     (b) If the fault continues:
  • Do step (13).
   (10) The center tank (left side) pump 1 is shown off.
     (a) Temporarily remove the FLSCU-1 (7QJ) from its rack AMM 28-46-34-000-001.
       1 Examine the FUEL page on the ECAM lower DU.
       2 If the center tank pump 1:
         a Operates correctly and shows on:
         b Shows off:
       3 If the fault continues:
         a Do a check of ASM 282104 and replace, if necessary, the:
  • RELAY-CTR TK AUTO CONTROL, PUMP 1 [41QA]
  • RELAY-CTR TK PUMPS 1 CTL [51QA]
  • RELAY-CTR TK LOW LEVEL, N#Auml# 1 [45QA]
  • RELAY-CTR TANK PUMP 1, LATCHED OFF (67QA)
  • RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
         b Do a wiring check of the aircraft wiring ASM 282104 between:
  • the FLSCU-1 rack connector 7QJ-AA, pin 11D and the RELAY-CTR TK PUMP 1 CTL (51QA), terminal A3 (logic 2/recirc. off (ground) wire)
  • the FLSCU-1 rack connector 7QJ-AA, pin 8B and the RELAY-CTR TK LO LVL, No 1 (45QA), terminal X2 (CTR TK low level 1 off (ground) wire)
  • the RELAY (45QA) terminal X2 and the RELAY (67QA), terminal A (CTR TK low level 1 off latch (ground) wire)
  • the RELAY (51QA) terminal A2 and the RELAY (41QA), terminal Z (CTR TK Pump 1 - Auto off (ground) wire)
  • the RELAY (67QA) terminal 4 and the RELAY (41QA), terminal Z (CTR TK Pump 1 - Auto off (ground) wire)
  • the RELAY (67QA) terminal 2 and the RELAY (14QU), terminal C3 (CTR TK low level 1 off latch (ground) wire).
         c Repair all the unserviceable wiring and connectors ESPM 2053210.
         d Do the test given in Para. 3.D.
     (b) If the fault continues:
  • Do step (13).
   (11) The center tank (right side) pump 2 is shown off.
     (a) Temporarily remove the FLSCU-2 (9QJ) from its rack AMM 28-46-34-000-001.
       1 Examine the FUEL page on the ECAM lower DU.
       2 If the center tank pump 2:
         a Operates correctly and shows on:
         b Shows off:
       3 If the fault continues:
         a Do a check of ASM 282104 and replace, if necessary, the:
  • RELAY-CTR TK AUTO CONTROL, PUMP 2 [42QA]
  • RELAY-CTR TK PUMPS 2 CTL [52QA]
  • RELAY-CTR TK LOW LEVEL, N#Auml# 2 [46QA]
  • RELAY-CTR TANK PUMP 2, LATCHED OFF (68QA)
  • RELAY-REFUEL/DEFUEL CTL PNL DOOR POSITION [14QU] .
         b Do a wiring check of the aircraft wiring ASM 282104 between:
  • the FLSCU-2 rack connector 9QJ-AA, pin 11D and the RELAY-CTR TK PUMP 2 CTL (52QA), terminal A3 (logic 2/recirc. off (ground) wire)
  • the FLSCU-2 rack connector 9QJ-AA, pin 8B and the RELAY-CTR TK LO LVL, No 2 (46QA), terminal X2 (CTR TK low level 2 off (ground) wire)
  • the RELAY (46QA) terminal X2 and the RELAY (68QA), terminal A (CTR TK low level 2 off latch (ground) wire)
  • the RELAY (52QA) terminal A2 and the RELAY (42QA), terminal Z (CTR TK Pump 2 - Auto off (ground) wire)
  • the RELAY (68QA) terminal 4 and the RELAY (42QA), terminal Z (CTR TK Pump 2 - Auto off (ground) wire)
  • the RELAY (68QA) terminal 2 and the RELAY (14QU), terminal D3 (CTR TK low level 2 off latch (ground) wire).
         c Repair all the unserviceable wiring and connectors ESPM 2053210.
         d Do the test given in Para. 3.D.
     (b) If the fault continues:
  • Do step (13).
   (12) If (the center-tank fuel-pump indications are correct) but the fault continues, do tests of the fuel output pressure from each of the three fuel pumps (on the applicable side of the aircraft) as follows:
     (a) Wing Tank Pumps
       1 Go to the AMM TASK, Installation of the Sequence Valve AMM 28-21-45-400-003.
       2 Do Para. 4.D. (Preparation for Test) thru Para. 4.G (Test of the Sequence Valve), on the L(R) wing tank fuel pump, No. 1.
       3 Make sure that the fuel pressure is as specified AMM 28-21-45-400-003.
NOTE: The fuel pressure given in the test is without a fuel transfer.
NOTE: The fuel output pressure of the wing tank fuel pumps is less than that of the center tank fuel pumps.
This is because the sequence valves act as relief valves:
  • reducing the fuel output pressure to allow the center tank fuel to be used first
  • returning their fuel output to the related wing tanks.
       4 If the fuel pressure is more than that specified:
       5 Do steps 1_ thru 4_ again on the L(R) wing tank fuel pump, No. 2.
     (b) Center Tank Pump
       1 Go to the AMM TASK, Installation of the Sequence Valve AMM 28-21-45-400-003.
NOTE: Sequence valves are not fitted to the center tank pumps but the fuel pump pressure can be tested using the same procedure.
The fuel output pressure of the center tank fuel pumps is more than that of the wing tank fuel pumps.
       2 Do Para. 4.D. (Preparation for Test) thru Para. 4.G. (Test of the Sequence Valve) on the center tank fuel pump, No. 1(2).
       3 Make sure that the fuel pressure for the center tank pumps is more than approximately 2.76 bar (40.0 psi).
NOTE: The fuel pressure given here for this test is without a fuel transfer.
       4 If the fuel pressure is less than that specified:
     (c) If the fault continues:
       1 Do more troubleshooting to find (investigate) the reason for the fuel-pump out of specification (high or low) fuel pressure and make sure that:
  • the fuel-pump pick up strainer and input pipe is clear
  • the fuel-pump/canister outlet pipe work is not blocked, damaged and/or leaking.
       2 Replace all the unserviceable fuel pipes and strainers.
       3 Do the test given in Para. 3.D.
     (d) If the fault continues:
  • Do step (13).
   (13) Replace the P/BSW-CTR TK/MODE SEL [48QA] .
     (a) Do the tests given in Para. 3. D.
[Rev.8 from Aug 2018] 2026.04.04 04:39:33 UTC
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