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

TASK 28-26-00-810-816-A
Fuel - Unwanted Transfer From The Left Or Right Wing Tank To The Center Tank At Any Time

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

1. Possible Causes

biological growth
loose (foreign) object
Left (Right) Main Transfer System Clack (moveable flap) Valve
clack valve seat
shroud
JET PUMP-L, CENTER TANK [157QM]
JET PUMP-R, CENTER TANK [158QM]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 28-12-00-810-801-A	Fuel - Unwanted Transfer From The Left Wing Tank To The Center Tank At Any Time
AMM 12-11-28-650-003	Pressure Refuel with Automatic Control
AMM 24-41-00-861-002	Energize the Aircraft Electrical Circuits from the External Power
AMM 28-11-00-280-002	Structural Fuel Tank Leaks - General Information
AMM 28-11-00-790-008	Leak Test with Fuel of the Wing Tank
AMM 28-25-00-650-001	Pressure Defuel
AMM 28-25-00-869-001	Fuel Transfer
AMM 28-26-00-210-001	Manually Operate the Transfer System Discharge Check Valve on RIB1 and Check For Full and Free Movement
AMM 28-26-00-710-001	Operational Test of the Main Transfer System
AMM 28-26-41-000-001	Removal of the Center Tank Jet Pump
AMM 28-26-41-400-001	Installation of the Center Tank Jet Pump
AMM 28-26-44-000-001	Removal of the Main-Transfer-System Clack Valve
AMM 28-26-44-400-001	Installation of the Main-Transfer-System Clack Valve
AMM 31-60-00-860-001	EIS Start Procedure

3. Fault Confirmation
Subtask 28-26-00-710-065-A ** ON A/C NOT FOR ALL

A. Test
(1) Energize the aircraft electrical circuits AMM 24-41-00-861-002.
(2) Do the EIS start procedure (ECAM only) AMM 31-60-00-860-001.
(3) On the ECAM Control Panel (CP), push (in) the FUEL pushbutton switch (P/BSW).
(4) Make sure that the FUEL page shows on the ECAM lower Display Unit (DU).
(5) Refuel AMM 12-11-28-650-003, defuel AMM 28-25-00-650-001 or transfer fuel AMM 28-25-00-869-001 to configure the fuel load as follows:

wing tank (on the side with the unwanted transfer) approximately 6000 kg (13230 lb)
center tank, approximately 150 kg (320 lb).

(6) On the ECAM lower DU (FUEL system display):
(a) Monitor the fuel quantities of the wing tank with the unwanted transfer and the center tank.
(b) Record the fuel quantities (when they have become stable after the refuel, defuel or transfer, in step (5)).
(7) Wait for five minutes:

NOTE: If there is an unwanted transfer route, gravity will cause a fuel flow to equalize the fuel levels.

(a) Monitor the fuel quantities of the wing tank with the unwanted transfer and the center tank.
(b) Record the fuel quantities.
(8) Use the fuel quantities (that you recorded) to see if there is an unwanted fuel transfer.

NOTE: No fuel transfer (measureable fuel quantity got from the FUEL system page/display) is permitted.

(9) If fuel from a wing tank:
(a) Does transfer, do the steps given in Para. 4.A.
(b) Does not transfer, do the Operational Test of the Main Transfer System AMM 28-26-00-710-001.

4. Fault Isolation
Subtask 28-26-00-810-065-A ** ON A/C NOT FOR ALL

A. Procedure
(1) Do a check of the Main-Transfer-System Clack (check) Valve AMM 28-26-00-210-001.
(a) Make sure that the valve:

moves freely
is not held open by a loose object, damage, corrosion or biological growth .

1 If necessary, remove the loose (foreign) object and find out where it came from.
(b) Make sure that the items that follow are serviceable.
If necessary, replace them AMM 28-26-44-000-001 and AMM 28-26-44-400-001:
1 The Left (Right) Main Transfer System Clack (moveable flap) Valve.
2 The clack valve seat .
3 The shroud .
(2) Replace the JET PUMP-L, CENTER TANK [157QM] ( JET PUMP-R, CENTER TANK [158QM] AMM 28-26-41-000-001 and AMM 28-26-41-400-001.

NOTE: This step is necessary because the jet pump contains a Non-Return Valve (NRV) flapper assembly in the secondary inlet. This NRV is in series with the transfer system clack valve. The two valves must be in the open (failed) position to give this unwanted fuel transfer.

No jet pump NRV maintenance parts are defined in the IPC.

(3) Do a leak test of the applicable wing tank Rib 1 AMM 28-11-00-790-008 and AMM 28-11-00-280-002. Repair, if necessary.
(4) If the unwanted transfer is between the:
(a) Right wing tank and the center tank, go to step (5).
(b) Left wing tank and the center tank, do Fuel - Unwanted Transfer From The Left Wing Tank To The Center Tank At Any Time (Ref. TSM TASK 28-12-00-810-801).

NOTE: This step (cross reference) is not applicable to an unwanted fuel transfer from the right wing tank to the center tank.

(5) Do the tests given in Para. 3.A.

[Rev.8 from Aug 2018] 2026.04.04 04:28:48 UTC