W DOC AIRBUS | TSM A320F

Unwanted Transfer Of Fuel From The Left Or Right Wing Tank To The Center Tank During Flight/Ground Phases When The Wing Tank Pumps Only Are In Operation

TASK 28-21-00-810-840-A
Unwanted Transfer Of Fuel From The Left Or Right Wing Tank To The Center Tank During Flight/Ground Phases When The Wing Tank Pumps Only Are In Operation

WARNING: OBEY THE FUEL SAFETY PROCEDURES.
1. Possible Causes
  • canister check valve, VALVE ASSY-OUTLET - Part of the CANISTER-PUMP, FUEL 84QM(85QM)
  • left-wing surge-tank scavenge system
  • jet adaptor assembly
  • JET PUMP-WATER SCAVENGE, L VENT SURGE TK [66QM]
  • CHECK VALVE-FUEL PUMP, L VENT SURGE TK [37QM]
  • LP fuel supply line
2. Job Set-up Information
 A. Referenced Information
REFERENCE
DESIGNATION
AMM 28-00-00-000-001
Removal of the Fuel Pipes
AMM 28-00-00-400-001
Installation of the Fuel Pipes
AMM 28-11-00-280-002
Structural Fuel Tank Leaks - General Information
AMM 28-11-00-790-002
Leak Test with Fuel of the Wing-Tank Outer and Inner Cells
AMM 28-21-00-720-004
Functional Test of the Center-Tank Fuel-Pump-Cannister Check-Valves
AMM 28-21-00-790-001
Leak Test of the Main Fuel-Pump-System Pipelines
AMM 28-21-43-000-003
Removal of the Fuel-Pump Check-Valve
AMM 28-21-43-400-003
Installation of the Fuel-Pump Check-Valve
AMM 28-21-52-000-004
Removal of the Check Valve of the Fuel Pump Canister
AMM 28-21-52-400-004
Installation of the Check Valve of the Fuel Pump Canister
AMM 28-21-53-000-001
Removal of the Jet Pump
AMM 28-21-53-000-003
Removal of the Jet Adaptor Assembly
AMM 28-21-53-400-001
Installation of the Jet Pump
AMM 28-21-53-400-003
Installation of the Jet Adaptor Assembly
AMM 57-17-11-000-001
Removal of the Access Covers 147AZ (148AZ)
TSM TASK 28-21-00-03
MAIN FUEL PUMP SYSTEM - TASK SUPPORTING DATA
3. Fault Confirmation
Subtask 28-21-00-710-086-B ** ON A/C NOT FOR ALL
A. Test
   (1) Read the MAINTENANCE NOTICE, FUEL PUMP CANISTER OUTLET VALVE (NRV) LEAKAGE/BACKFLOW 28-21-00-03 TSM TASK 28-21-00-03 before you do more steps.
   (2) Record which side of the aircraft is the cause of the fuel migration:
  • do a Functional Test of the applicable Center-Tank Fuel-Pump-Canister Check-Valve AMM 28-21-00-720-004.
NOTE: The functional test uses the related wing tank fuel pumps to test the center tank canister check valves in the closed position.
Only a very small fuel leakage rate of 3 litres per hour is permitted.
The functional test referred to does not use the Fuel Quantity Indicating System (FQIS). This is because the ECAM tank fuel quantity values are given in increments (steps) of 10kg (20lb).
To detect any fuel leakage with the FQIS at the permitted leak rate the wing tank fuel pumps would have to be left running for a minimum of approximately five (5) hours.
   (3) If the functional test of the center tank fuel pump canister check valve:
     (a) Does not operate as specified, and the leakage rate is greater than that specified:
  • go to Para. 4.A.
     (b) Operates as specified:
  • go to Para. 4.A.(3).
4. Fault Isolation
Subtask 28-21-00-810-086-B ** ON A/C NOT FOR ALL
A. Procedure
   (1) Replace the canister check valve, VALVE ASSY-OUTLET - Part of the CANISTER-PUMP, FUEL 84QM(85QM) AMM 28-21-52-000-004 and AMM 28-21-52-400-004.
   (2) Do the test given in Para. 3.A.
   (3) If the functional test of the applicable center tank canister check valve was as specified or if the fault continues in further flights:
   (4) Do a Leak Test of the Main Fuel-Pump-System Pipelines in the center tank AMM 28-21-00-790-001.
   (5) If the unwanted fuel transfer/migration is from:
     (a) The aircrafts left side:
       1 Do a check of and replace, if necessary, the items of the left-wing surge-tank scavenge system that follow:
NOTE: If the jet pump 66QM is inoperative, the fuel-level in the left-wing vent/surge-tank can increase until it is above the level of the center-tank vent (duct/outlet-pipe at RIB22). Fuel can then flow through the center-tank vent and enter the center tank.
         a The jet adaptor assembly AMM 28-21-53-000-003 and AMM 28-21-53-400-003.
         b The JET PUMP-WATER SCAVENGE, L VENT SURGE TK [66QM] AMM 28-21-53-000-001 and AMM 28-21-53-400-001.
         c The CHECK VALVE-FUEL PUMP, L VENT SURGE TK [37QM] AMM 28-21-43-000-003 and AMM 28-21-43-400-003.
         d The jet-pump (feed/drive supply) pipe-line, between the fuel-manifold (adjacent to the check valves 33QM and 34QM, in-board of RIB2) and the jet-pump 66QM.
         e The jet-pump (suction) pipe-line, between the suction inlet pickup point in the left-wing vent/surge-tank and the jet-pump 66QM.
         f The jet-pump (output/discharge) pipe-line, between the jet-pump 66QM and the fuel discharge (outlet) adjacent to the intercell transfer valve 28QM (outboard of RIB15).
       2 Do a check (examination) of the LP fuel supply line (in the center tank) between:
  • the left sealed RIB1 tank wall and the left fuel pump canister 84QM
  • the left sealed RIB1 tank wall and the crossfeed valve 10QM
  • the left sealed RIB1 tank wall and the APU LP fuel supply line where it passes through the rear spar/tank wall.
     (b) The aircrafts right side:
       1 Do a check (examination) of the LP fuel supply line (in the center tank) between:
  • the right sealed RIB1 tank wall and the right fuel pump canister 85QM
  • the right sealed RIB1 tank wall and the crossfeed valve 10QM
  • the right sealed RIB1 tank wall and the defuel/transfer valve 11QM.
   (6) Repair/replace all the unserviceable fuel pipes and connections AMM 28-00-00-000-001 and AMM 28-00-00-400-001.
   (7) Do the test given in step (4).
   (8) If the fault continues:
  • do a leak test of the applicable left (right) RIB1 using the Leak Test of the Wing-Tank Outer and Inner Cells AMM 28-11-00-790-002.
   (9) Repair all the leaks in the applicable RIB1.
See Fuel Tank Leak Checks AMM 28-11-00-280-002.
   (10) Do the test given in step (8).
[Rev.8 from Aug 2018] 2026.04.04 04:28:38 UTC
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