MAIN TRANSFER SYSTEM - DESCRIPTION AND OPERATION

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1. General
The main transfer system controls the flow of the fuel from the center (transfer) tank to the two wing tanks.
The system uses jet pumps to move the fuel from the center (transfer) tank to the wing tanks.
Fuel Level Sensing Control Unit (FLSCU) 1 and 2 (Ref. AMM D/O 28-46-00-00) automatically controls the system, if necessary, the crew can manually control it from the cockpit.
The Engine/Warning Display (EWD) (Ref. AMM D/O 31-66-00-00) and the System Display (SD) (which together make the ECAM) give main transfer system information to the crew. If specified failures occur:

a warning is given on the EWD
the FUEL page shows on the SD.

When necessary the crew can make a selection on the ECAM control panel (Ref. AMM D/O 31-56-00-00) to look at the FUEL page.

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2. Component Location

Main Transfer System - Component Location (Center (Transfer) Tank) ** ON A/C NOT FOR ALL

Main Transfer System - Component Location (Cockpit) ** ON A/C NOT FOR ALL

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
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157QM	JET PUMP-L, CENTER TANK		141	28-26-41
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158QM	JET PUMP-R, CENTER TANK		121	28-26-41
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157QM	JET PUMP-L, CENTER TANK	147AZ	141	28-26-41
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220QM	STRAINER-JET PUMP L, CENTER TANK		141	28-26-42
221QM	STRAINER-JET PUMP R, CENTER TANK		142	28-26-42
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220QM	STRAINER-JET PUMP L, CENTER TANK	147AZ	141	28-26-42
221QM	STRAINER-JET PUMP R, CENTER TANK	148AZ	142	28-26-42
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11QL	ACTUATOR-JET PUMP 1 CTL VALVE, CTR TK		195	28-26-51
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11QL	ACTUATOR-JET PUMP 1 CTL VALVE,CTR TK	195AB	195	28-26-51
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12QL	ACTUATOR-JET PUMP 2 CTL VALVE, CTR TK		196	28-26-51
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12QL	ACTUATOR-JET PUMP 2 CTL VALVE, CTR TK	196AB	196	28-26-51
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155QM	CLAMP-V BAND		195	28-10-00
156QM	CLAMP-V BAND		196	28-10-00
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153QM	FUEL CONTROL VALVE-JET PUMP, L WING TK		141	28-26-43
154QM	FUEL CONTROL VALVE-JET PUMP, R WING TK		142	28-26-43
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155QM	CLAMP-V BAND	195AB	195	28-10-00
156QM	CLAMP-V BAND	196AB	196	28-10-00
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153QM	FUEL CONTROL VALVE-JET PUMP, L WING TK	147AZ	141	28-26-43
154QM	FUEL CONTROL VALVE-JET PUMP, R WING TK	148AZ	142	28-26-43

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3. System Description
The main transfer system has these components:

a jet pump 157QM(158QM)
a strainer 220QM(221QM)
a control valve 153QM(154QM)
a control valve actuator 11QL(12QL).

FLSCU 1 (7QJ) (FLSCU 2 (9QJ)) (Ref. AMM D/O 28-46-00-00) automatically controls the transfer system through control valve 153QM (154QM).
When the control valve is open, fuel from the main pumps (Ref. AMM D/O 28-21-00-00) flows through the control valve and the nozzle in the jet pump 157QM (158QM).
The flow of the fuel through the nozzle causes a suction in the jet pump.
This suction removes the fuel from the center (transfer) tank, through strainer 220QM (221QM) and moves it (together with the fuel from the main pumps) to the related wing tank.

Main Transfer System - Component Location (Cockpit) ** ON A/C NOT FOR ALL

The crew can control the transfer system from the cockpit through the CTR TK XFR and the MODE SEL pushbutton switches on HYD/FUEL panel 40VU. When the MODE SEL pushbutton switch (4QL) is released (the MAN legend comes on), the automatic control of the transfer system stops. In this configuration, when the CTR TK XFR pushbutton switches (5QL, 6QL) are pushed (the ON legends come on), the related control valve is opened and transfer starts. When the CTR TK XFR pushbutton switches are released (the OFF legend comes on), the related control valve is closed and transfer stops.
After the fuel transfer, there is a risk of surge tank overflow if the MODE SEL pushbutton switch (4QL) stays in the MAN mode.

Control Valve and Control Valve Actuator - Location ** ON A/C NOT FOR ALL

The control valve 153QM(154QM) is attached to the bottom skin of the center (transfer) tank as follows:

the LH control valve between FR36 and FR42 (LH side)
the RH control valve between FR36 and FR42 (RH side).

The valve has a spindle that goes through the tank skin to engage with the related control valve actuator 11QL(12QL). The actuator is attached to the outer bottom face of the center (transfer) tank. When energized, the actuator moves the related control valve to the open or closed position. The V-band clamp 155QM(156QM) attaches the control valve to the control valve actuator.

Jet Pump and Strainer - Location ** ON A/C NOT FOR ALL

The jet pump 157QM(158QM) and its related strainer 220QM(221QM) is attached to the bottom skin of the center (transfer) tank as follows:

the LH jet pump and strainer between FR36 and FR42 (LH side)
the RH jet pump and strainer between FR36 and FR42 (RH side).

The strainers remove contamination from the fuel before it goes through the jet pumps.
A check valve is installed in the end of the transfer pipe. The check valve stops the movement of fuel from the wing tank collector-cell to the center (transfer) tank.

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4. Power Supplies

Main Transfer System Manual Control System 1 (LH) - Electrical Schematic ** ON A/C NOT FOR ALL

Main Transfer System Automatic Control - Electrical Schematic ** ON A/C NOT FOR ALL

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5. Interface

Main Transfer System - Interfaces ** ON A/C NOT FOR ALL

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6. Component Description

A. Jet Pump FIN: 157-QM FIN: 158-QM

Jet Pump and Strainer - Detail ** ON A/C NOT FOR ALL

The jet pump has:

an inlet body
a jet pump body
a jet nozzle
a non-return valve
an outlet body.

The jet pump body is connected to the inlet body and the outlet body. The jet pump body fully contains the jet nozzle. The jet pump has two fuel inlets, the pressure inlet and the suction inlet. The jet pump body has a flange at the suction inlet. The flange attaches the strainer 220QM(221QM) to the jet pump and attaches the jet pump to the bottom skin of the tank.
When fuel from the pressure inlet goes through the jet nozzle, it causes a suction at the suction inlet. The flow of fuel goes through and out of the jet pump outlet body. The non-return valve prevents an opposite flow through the jet pump.

B. Strainer 220QM(221QM)

Jet Pump and Strainer - Detail ** ON A/C NOT FOR ALL

The strainer is a wire mesh cage with a flange at one end. The strainer is attached to the jet pump at this flange. The strainer removes contamination from the fuel that enters the related jet pump.

C. Control Valve

Control Valve 153QM(154QM) and Control Valve Actuator 11QL(12QL) ** ON A/C NOT FOR ALL

The primary components of the control valve are:

the valve body with a mounting flange
the ball valve with its valve spindle
the drive assembly.

The valve body holds the ball valve which has a bore of 38.1 MM (1.5 IN.). The ball valve has a master key-way that engages with the valve spindle. The valve spindle also has a master key-way that engages with the drive assembly.

The mounting flange of the valve body is attached to the upper face of the center (transfer) tank bottom skin with four studs and two countersunk bolts. The studs also attach the drive assembly to the lower face of the center (transfer) tank bottom skin. The drive assembly has a flange to which the actuator is attached and a location slot to make sure the actuator engages correctly. A set of O-ring seals prevent a leakage of fuel through the mounting flange.

D. Control Valve Actuator 11QL(12QL)

Control Valve 153QM(154QM) and Control Valve Actuator 11QL(12QL) ** ON A/C NOT FOR ALL

The actuator has an electrical motor that drives a differential gear to turn the ball valve through 90 deg. Limit switches in the actuator control this 90 deg. movement and set the electrical circuit for the next operation. A V-Band clamp attaches the actuator to the flange of the drive assembly. A location peg makes sure that the actuator engages correctly. The see/feel indicator gives an indication of the valve position without removal of the actuator.

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7. Operation/Control and Indicating

Main Transfer System Automatic Control - Electrical Schematic ** ON A/C NOT FOR ALL

Main Transfer System Manual Control System 1 (LH) - Electrical Schematic ** ON A/C NOT FOR ALL

The main transfer system is usually controlled automatically, but it can be controlled manually when necessary. For system operation it is necessary to have:

the 28VDC BUS 1 (103PP) and the 28VDC BUS 2 (204PP) energized
the circuit breakers 1QL, 2QL and 3QL closed.

A. Automatic Operation

Main Transfer System - Component Location (Cockpit) ** ON A/C NOT FOR ALL

FLSCU 1 (7QJ) (FLSCU 2 (9QJ)) automatically controls the main transfer system when you:

Push in the MODE SEL pushbutton switch (4QL)
Push in (ON) the CTR TK L XFR (CTR TK R XFR) pushbutton switch (5QL, 6QL).

The control valves (153QM, 154QM) will open or close automatically, these operate independently. The jet pumps (157QM, 158QM) will supply fuel to the related wing tank as necessary, when the control valves are open.

NOTE: The transfer control valve will close when two FULL sensors 23QJ1 (23QJ2) and 27QJ1 (27QJ2) from the same wing becomes wet.

The main transfer system operates as follows:

The auto control relays (7QL, 8QL) are energized and the control valves receive the signals to open independently
A control valve will not open if two FULL sensors 23QJ1 and 27QJ1 (23QJ2 and 27QJ2) are wet
A control valve will open when a minimum of one UNDERFULL sensors 24QJ1, 25QJ1 and 26QJ1 (24QJ2, 25QJ2 and 26QJ2) is dry and the related LOW LVL sensor 21QJ (22QJ) is wet
The control valves will close when FULL sensors 23QJ1 (23QJ2) and 27QJ1 (27QJ2) from the same wing becomes wet
The time delay relay (9QL, 10QL) receives a signal when the related LOW LVL sensor (21QJ, 22QJ) becomes dry. The related control valve stays open for five minutes and then closes
If a LOW LVL (21QJ, 22QJ) sensor becomes wet during this five minute period, the related control valve will stay open. This cycle continues until the LOW LVL sensor stays dry for the five minute period. The related control valve then closes and the center (transfer) tank is empty
If the LOW LVL sensor (21QJ, 22QJ) becomes wet during flight, the five minute period will start again. The center tank transfer pumps do not latch off after the initial five minute period is completed.

B. Manual Operations
The crew has manual control of the transfer system when they:

Release the MODE SEL pushbutton switch (4QL) (the MAN legend comes on)
Push the CTR TK L XFR (CTR TK R XFR) pushbutton switch (the ON legend comes on).

After the fuel transfer, there is a risk of surge tank overflow if the MODE SEL pushbutton switch (4QL) stays in the MAN mode.
In this configuration the jet pumps will run continuously until the CTR TK L XFR (CTR TK R XFR) P/BSW is released out (OFF).

C. Main Transfer System Fault Indication

(1) P/BSW FAULT annunciators

The main transfer system has FAULT annunciators on:

the MODE SEL P/BSW
the CTR TK L XFR (CTR TK R XFR) P/BSW.

If a fault occurs in the main transfer system:

the related FAULT annunciator will come on
the failure message FUEL L(R) XFR VALVE FAULT will be shown on ECAM.

The FAULT annunciator of the MODE SEL P/BSW will only come on in the AUTO configuration. If the FAULT annunciator of the MODE SEL P/BSW comes on, the P/BSW must be set to MAN. The crew then have manual control of the main transfer system.
The FAULT annunciator of the CTR TK L XFR (CTR TK R XFR) P/BSW can come on in the AUTO or the MAN configuration. If a FAULT annunciator of one of the CTR TK XFR P/BSWs comes on, that P/BSW must be set to OFF.
If one of the CTR TK XFR P/BSWs is set to OFF:

fuel will transfer from the center (transfer) tank to one wing tank only
the crew must crossfeed fuel (Ref. AMM D/O 28-23-00-00) from one wing tank to the other to keep the aerodynamic balance of the aircraft.

Gravity transfers fuel from the center (transfer) tank if the the two CTR TK XFR P/BSWs are set to OFF. Fuel only gravity transfers to the wing tanks when the level of fuel in the center (transfer) tank is greater than that in the wing tanks. When gravity transfer is in operation, approximately 2000 kg (4409 lb) of unusable fuel will remain in the center (transfer) tank.

(2) SD FUEL page XFR-valve-indications

SD FUEL Page XFR Valve indications ** ON A/C NOT FOR ALL

SD FUEL page XFR-valve-indications ** ON A/C NOT FOR ALL

SD FUEL Page XFR Valve indications ** ON A/C NOT FOR ALL

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8. BITE Test
Not applicable

[Rev.10 from 2021] 2026.04.02 07:01:13 UTC