Fuel - Unwanted Transfer From The Left Wing Tank To The Center Tank At Any Time

TASK 28-12-00-810-801-A
Fuel - Unwanted Transfer From The Left Wing Tank To The Center Tank At Any Time

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

1. Possible Causes

CTR TK HI LEVEL SENSOR 20QJ
left-wing surge-tank scavenge system
jet adaptor assembly
JET PUMP-WATER SCAVENGE, L VENT SURGE TK or JET PUMP-WATER SCAVENGE, L VENT SURGE TK [66QM]
CHECK VALVE-FUEL PUMP, L VENT SURGE TK [37QM]
PROTECTOR-OVERPRESSURE, CTR TK [96QM]
VALVE-PRESSURE RELIEF, CTR TK [97QM]
center tank vent pipe
VALVE-REFUEL, CTR TK [10QU]
left-wing surge-tank fuel return system
CLACK VALVE [214QM]
CLACK VALVE [216QM]

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 28-11-00-790-003	Leak Test of the Center Tank
AMM 28-11-42-000-002	Removal of the Clack Valve
AMM 28-11-42-400-002	Installation of the Clack Valve
AMM 28-12-00-200-001	Inspection of the Tank Venting System
AMM 28-12-41-000-003	Removal of the Overpressure Protector
AMM 28-12-41-200-002	Inspection of the Overpressure Protector
AMM 28-12-41-400-003	Installation of the Overpressure Protector
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 28-21-53-000-001	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 28-25-00-710-003	Operational Test of the Refuel System
AMM 28-25-45-000-001	Removal of the Center-Tank Pressure-Relief Valve
AMM 28-25-45-400-001	Installation of the Center-Tank Pressure-Relief Valve
AMM 28-25-51-000-002	Removal of the Refuel Valve
AMM 28-25-51-400-002	Installation of the Refuel Valve
AMM 28-46-00-740-001	Functional (BITE) Test
SRM 517612
AMM 51-76-12-300-001	Local Repair of the Fuel Tank Sealant
AMM 51-76-12-300-002	Repair of the Fuel Tank Fillet

3. Fault Confirmation
Subtask 28-12-00-710-050-A

A. Prerequisite Test
(1) Open the REFUEL panel door 192MB/522KB/622KB (or if installed,
at REFUEL panel 51VU, set the cockpit refuel PWR P/BSW (23QU) to on).

NOTE: This step is necessary to energize the 28VDC FUELING BUS. If this step is not done the high level sensor channels will not be tested during the FLSS BITE test that follows.

(2) Do the FLSS BITE Test AMM 28-46-00-740-001.
(3) Examine the FLSS STATUS page for any of the FUEL LEVEL SENSING messages that follow:

CTR TK HI LEVEL SENSOR 20QJ
L(R) HI LEVEL SENSOR 17QJ1(2)
FLSCU1(2) 7(9)QJ.

(4) If none of the messages given in step (3) are shown:

go to Para. 4.

(5) If one or more of the messages given in step (3) are shown:

troubleshoot the LRU(s) and then go to Para. 4.
Refer to the Fault Symptoms, at the front of the TSM and/or chapter 28, for the related Task number.

4. Fault Isolation
Subtask 28-12-00-810-050-A ** ON A/C NOT FOR ALL

A. Procedure

NOTE: Read all of the steps (1) and (2) before you start work.
The order in which the work steps are done is best decided by the maintenance staff in conjunction with:

other malfunction indications
the fuel configuration
the aircraft location.

(1) Do a check of and replace, if necessary, the items of the left-wing surge-tank scavenge system that follow:

NOTE: During aircraft operations on the ground and in flight, fuel can collect in the vent/surge-tank. If this occurs, a jet pump scavenge system moves the fuel into the related wing-tank outer-cell.
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 by the effect of gravity.

(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 or 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 pressurized-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-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).
(g) Repair/replace all the unserviceable fuel pipes and connections AMM 28-00-00-000-001 and AMM 28-00-00-400-001.
(2) Do the Inspection of the (Center Tank) Overpressure Protector 96QM AMM 28-12-41-200-002.

NOTE: The function of the overpressure protector 96QM is to protect the center tank structure from possible damage.
The operation of the overpressure protector 96QM will safely release the (unwanted) pressure to the atmosphere through the left wing tank ventilation system.
The defects that follow (and/or) can cause the over pressure protector 96QM to break/operate:

the center tank vent pipe is blocked
the pressure relief valve 97QM cannot open, or cannot open quickly enough or sufficiently enough to release the (unwanted) pressure safely to the atmosphere through the right wing tank ventilation system.

(a) If the overpressure protector 96QM is serviceable:

do a leak test of the RIB1 for leaks between the center tank and the left wing collector cell AMM 28-11-00-790-003.

1 Repair all the leaks:

(b) If the (frangible) overpressure protector 96QM has operated (is broken), it is important do all the steps that follow to find what caused it to break.

NOTE: The reasons why a burst disc can break are as follows:

a defective/unserviceable disk (non standard)
that breaks below the (its) correct operating pressure
a serviceable disk
that operated because the pressure difference between the center tank and the adjacent left wing tank was more than the correct safe operating pressure.

1 Replace the PROTECTOR-OVERPRESSURE, CTR TK [96QM] AMM 28-12-41-000-003 and AMM 28-12-41-400-003.
2 Do a check of the pressure relief valve 97QM as follows:
a Get access to the pressure relief valve 97QM AMM 28-12-41-200-002.
b Do a visual check of the pressure relief valve 97QM to see if it:

has become blocked
can open (functionally operate) with a full and free movement.

c If necessary, remove any blockage/obstruction or replace the VALVE-PRESSURE RELIEF, CTR TK [97QM] AMM 28-25-45-000-001 and AMM 28-25-45-400-001.
3 Do an inspection of the center tank vent pipe AMM 28-12-00-200-001.
a If necessary, replace any damaged or blocked section(s) of the center tank vent pipe .
4 Do a check of the center tank refuel valve 10QU as follows:
a Remove the center tank refuel valve 10QU.
b Do a visual inspection of the refuel valve 10QU, valve position.
c If the valve is (stays) in the open position, replace the VALVE-REFUEL, CTR TK [10QU] AMM 28-25-51-000-002 and AMM 28-25-51-400-002.
d If the valve is in the closed position or if the valve is replaced in step c_, do an operational test of the center tank refuel valve 10QU (to see if it can open and close) AMM 28-25-00-710-003.
e If there is any malfunction of the refuel valve 10QU and/or related sub-systems, refer to the Fault Symptoms (at the front of the TSM and/or chapter 28, for the related Task number) and do the necessary troubleshooting.
(c) If, when all the tests and inspections are complete:
1 The cause(s) of the operation of the overpressure protector 96QM (broken/damaged) has(have) been found (and all the unserviceable LRUs have been replaced):
a Refuel the aircraft and return to service.
2 No cause of the operation of the over pressure protector 96QM (broken/damaged) is found and all the serviceable LRUs have been replaced:
a Put the aircraft back into operation.
b Send the unserviceable overpressure protector 96QM to the vendor.
c If the fault continues, refer the problem to AIRBUS.

Subtask 28-12-00-810-050-C ** ON A/C NOT FOR ALL

A. Procedure

NOTE: Read all of the steps (1) and (2) before you start work.
The order in which the work steps are done is best decided by the maintenance staff in conjunction with:

other malfunction indications
the fuel configuration
the aircraft location.

(1) Do a check of AMM 28-12-00-200-001 and replace, if necessary, the items of the left-wing surge-tank fuel return system that follow:

NOTE: During aircraft operations on the ground and in flight, fuel can collect in the vent/surge-tank. If this occurs, clack valves that form a fuel return system let fuel move into the related wing-tank.
If the clack valves 214QM and 216QM are inoperative (in the closed position), 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 by the effect of gravity.

the CLACK VALVE [214QM] AMM 28-11-42-000-002 and AMM 28-11-42-400-002
the CLACK VALVE [216QM] AMM 28-11-42-000-002 and AMM 28-11-42-400-002.

(2) Do the Inspection of the (Center Tank) Overpressure Protector 96QM AMM 28-12-41-200-002.

the center tank vent pipe is blocked
the pressure relief valve 97QM cannot open, or cannot open quickly enough or sufficiently enough to release the (unwanted) pressure safely to the atmosphere through the right wing tank ventilation system.

(a) If the overpressure protector 96QM is serviceable:

do a leak test of the RIB1 for leaks between the center tank and the left wing collector cell AMM 28-11-00-790-003.

1 Repair all the leaks:

(b) If the (frangible) overpressure protector 96QM has operated (is broken), it is important do all the steps that follow to find what caused it to break:

NOTE: The reasons why a burst disc can break are as follows:

a defective/unserviceable disk (non standard)
that breaks below the (its) correct operating pressure
a serviceable disk
that operated because the pressure difference between the center tank and the adjacent left wing tank was more than the correct safe operating pressure.

has become blocked
can open (functionally operate) with a full and free movement.

c If necessary, remove any blockage/obstruction or replace the VALVE-PRESSURE RELIEF, CTR TK [97QM] AMM 28-25-45-000-001 and AMM 28-25-45-400-001.
3 Do an inspection of the center tank vent pipe AMM 28-12-00-200-001.
a If necessary, replace any damaged or blocked section(s) of the center tank vent pipe .
4 Do a check of the center tank refuel valve 10QU as follows:
a Remove the center tank refuel valve 10QU.
b Do a visual inspection of the refuel valve 10QU, valve position.
c If the valve is (stays) in the open position, replace the VALVE-REFUEL, CTR TK [10QU] AMM 28-25-51-000-002 and AMM 28-25-51-400-002.
d If the valve is in the closed position or if the valve is replaced in step c_, do an operational test of the center tank refuel valve 10QU (to see if it can open and close) AMM 28-25-00-710-003.
e If there is any malfunction of the refuel valve 10QU and/or related sub-systems, refer to the Fault Symptoms (at the front of the TSM and/or chapter 28, for the related Task number) and do the necessary troubleshooting.
(c) If, when all the tests and inspections are complete:
1 The cause(s) of the operation of the overpressure protector 96QM (broken/damaged) has(have) been found (and all the unserviceable LRUs have been replaced):
a Refuel the aircraft and return to service.
2 If no cause of the operation of the overpressure protector 96QM (broken/damaged) is found and all the unserviceable LRUs have been replaced:
a Put the to aircraft back into operation.
b Send the unserviceable overpressure protector 96QM to the vendor.
c If the fault continues, refer the problem to AIRBUS.

[Rev.8 from Aug 2018] 2026.04.04 04:39:25 UTC