MAIN FUEL PUMP SYSTEM - DESCRIPTION AND OPERATION

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1. General
The main fuel pump system supplies the fuel from the wing tanks to the engines. The system has four main fuel pumps (main pumps), two in each wing. The main pumps in each wing operate together to supply fuel to their related engine.
The main fuel pump system supplies the fuel from the fuel tanks to the engines. The system has six main fuel pumps (main pumps):

two in each wing tank
two in the center tank.

The main pumps in each wing operate together continuously to supply fuel to their related engine.
The Fuel Level Sensing Control Units (FLSCUs) (Ref. AMM D/O 28-46-00-00) normally control the main pumps in the center tank automatically. They supply fuel to their related engine during flight when the fuel in the wing tank is below a specified level. The wing tank pumps each have a sequence valve that makes sure the center tank fuel is supplied to the engines first.
The crossfeed system (Ref. AMM D/O 28-23-00-00), when closed, divides the main fuel pump system into two parts, one part for each engine. If one wing tank main pump has a failure (or it is set to OFF) the other will continue to supply fuel to its related engine.
When the crossfeed system is open, it is possible for one fuel pump to supply fuel to the two engines.

The system has valves that automatically bleed the air from the engine feed-pipes during fuel pump operation.

The Engine/Warning Display (EWD) (Ref. AMM D/O 31-66-00-00) and the System Display (SD) (which together make the ECAM) give system data 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 Fuel Pump System ** ON A/C NOT FOR ALL

Main Fuel-Pump System ** ON A/C NOT FOR ALL

Main Fuel Pump Scavenge System ** ON A/C NOT FOR ALL

Main Fuel-Pump Scavenge-System ** ON A/C NOT FOR ALL

Main Fuel Pump System ** ON A/C NOT FOR ALL

FIN	FUNCTIONAL DESIGNATION	PANEL	ZONE	ATA REF
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21QA	PUMP-FUEL NO 1, L WING TK	540AB	540	28-21-51
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21QA	PUMP-FUEL NO 1, L WING TK		540	28-21-51
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22QA	PUMP-FUEL NO 1, R WING TK	640AB	640	28-21-51
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22QA	PUMP-FUEL NO 1, R WING TK		640	28-21-51
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25QA	PUMP-FUEL NO 2, L WING TK	540AB	540	28-21-51
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25QA	PUMP-FUEL NO 2, L WING TK		540	28-21-51
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26QA	PUMP-FUEL NO 2, R WING TK	640AB	640	28-21-51
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26QA	PUMP-FUEL NO 2, R WING TK		640	28-21-51
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23QA	PRESS SW-FUEL PUMP NO 1, L WING TK	571AB	570	28-21-15
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23QA	PRESS SW-FUEL PUMP NO 1, L WING TK		570	28-21-15
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24QA	PRESS SW-FUEL PUMP NO 1, R WING TK	671AB	670	28-21-15
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24QA	PRESS SW-FUEL PUMP NO 1, R WING TK		670	28-21-15
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27QA	PRESS SW-FUEL PUMP NO 2, L WING TK	571AB	570	28-21-15
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27QA	PRESS SW-FUEL PUMP NO 2, L WING TK		570	28-21-15
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28QA	PRESS SW-FUEL PUMP NO 2, R WING TK	671AB	670	28-21-15
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28QA	PRESS SW-FUEL PUMP NO 2, R WING TK		670	28-21-15
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149QM	CHECK VALVE		540	28-21-43
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149QM	CHECK VALVE	540AB	540	28-21-43
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150QM	CHECK VALVE		540	28-21-43
151QM	CHECK VALVE		640	28-21-43
152QM	CHECK VALVE		640	28-21-43
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150QM	CHECK VALVE	540AB	540	28-21-43
151QM	CHECK VALVE	640AB	640	28-21-43
152QM	CHECK VALVE	640AB	640	28-21-43
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1QM	CANISTER-FUEL PUMP, L WING TK OUTR	540AB	540	28-21-52
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1QM	CANISTER-FUEL PUMP, L WING TK OUTR		540	28-21-52
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3QM	CANISTER-FUEL PUMP, R WING TK INR	640AB	640	28-21-52
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3QM	CANISTER-FUEL PUMP, R WING TK INR		640	28-21-52
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2QM	CANISTER-FUEL PUMP, L WING TK INR	540AB	540	28-21-52
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2QM	CANISTER-FUEL PUMP, L WING TK INR		540	28-21-52
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4QM	CANISTER-FUEL PUMP, R WING TANK OUTER	640AB	640	28-21-52
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4QM	CANISTER-FUEL PUMP, R WING TANK OUTER		640	28-21-52
** ON A/C ALL
5QM	STRAINER-PUMP INLET, L WING TK OUTR	540AB	540	28-21-54
7QM	STRAINER-PUMP INLET, R WING TK INR	640AB	640	28-21-54
6QM	STRAINER-PUMP INLET, L WING TK INR		540	28-21-54
8QM	STRAINER-PUMP INLET, R WING TK OUTR	640AB	640	28-21-54
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86QM	VALVE-AIR RELEASE, L WING TK	540CB	540	28-21-41
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86QM	VALVE-AIR RELEASE, L WING TK		540	28-21-41
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87QM	VALVE-AIR RELEASE, R WING TK	640CB	640	28-21-41
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87QM	VALVE-AIR RELEASE, R WING TK		640	28-21-41
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33QM	CHECK VALVE-FUEL PUMP,L WING TK OUTR	540AB	540	28-21-43
34QM	CHECK VALVE-FUEL PUMP, L WING TK INR	540AB	540	28-21-43
35QM	CHECK VALVE-FUEL PUMP, R WING TK INR	640AB	640	28-21-43
36QM	CHECK VALVE-FUEL PUMP, R WING TK OUTR	640AB	640	28-21-43
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37QM	CHECK VALVE-FUEL PUMP, L VENT SURGE TK	540AB	540	28-21-43
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37QM	CHECK VALVE-FUEL PUMP, L VENT SURGE TK		540	28-21-43
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38QM	CHECK VALVE-FUEL PUMP, R VENT SURGE TK	640AB	640	28-21-43
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38QM	CHECK VALVE-FUEL PUMP, R VENT SURGE TK		640	28-21-43
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66QM	JET PUMP-WATER SCAVENGE, L VENT SURGE TK	540KB	540	28-21-53
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66QM	JET PUMP-WATER SCAVENGE, L VENT SURGE TK		540	28-21-53
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67QM	JET PUMP-WATER SCAVENGE, L WING TK	540KB	540	28-21-53
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67QM	JET PUMP-WATER SCAVENGE, L WING TK		540	28-21-53
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68QM	JET PUMP-WATER SCAVENGE, R WING TK	640KB	640	28-21-53
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68QM	JET PUMP-WATER SCAVENGE, R WING TK		640	28-21-53
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69QM	JET PUMP-WATER SCAVENGE, R VENT SURGE TK		640	28-21-53
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69QM	JET PUMP-WATER SCAVENGE, R VENT SURGE TK		640	28-21-53
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37QA	PUMP-FUEL NO 1, CTR TK	195AB	195	28-21-51
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37QA	PUMP-FUEL NO 1, CTR TK		195	28-21-51
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38QA	PUMP-FUEL NO 2, CTR TK	196AB	196	28-21-51
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38QA	PUMP-FUEL NO 2, CTR TK		196	28-21-51
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84QM	CANISTER-FUEL PUMP, L CTR TK		141	28-21-52
85QM	CANISTER-FUEL PUMP, R CTR TK		142	28-21-52
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39QA	PRESS SW-FUEL PUMP NO 1, CTR TK		147	28-21-15
40QA	PRESS SW-FUEL PUMP NO 2, CTR TK		148	28-21-15
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89QM	JET PUMP-WATER SCAVENGE, L CTR TK	147AZ	141	28-21-53
90QM	JET PUMP-WATER SCAVENGE, R CTR TK	148AZ	142	28-21-53

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3. System Description
The main fuel pump system has these components:

the fuel strainers 5QM(7QM), 6QM(8QM)
the fuel pumps 21QA(22QA), 25QA(26QA)
the fuel pump canisters 1QM(3QM), 2QM(4QM)
the check valves 149QM(151QM), 150QM(152QM)
the engine fuel-feed air-release valves 86QM(87QM)
the fuel pump pressure switches 23QA(24QA), 27QA(28QA).

The main fuel pump system has these components:

the fuel strainers 5QM(7QM), 6QM(8QM)
the fuel pumps 21QA(22QA), 25QA(26QA), 37QA(38QA)
the fuel pump canisters 1QM(3QM), 2QM(4QM), 84QM(85QM)
the fuel pump pressure switches 23QA(24QA), 27QA(28QA), 39QA(40QA)
the check valves 33QM(36QM), 34QM(35QM), 37QM(38QM)
the scavenge jet pumps 67QM(68QM), 66QM(69QM), 89QM(90QM)
the engine fuel-feed air-release valves 86QM(87QM).

The main fuel-pump system has these components:

Fuel strainers 5QM(8QM) and 6QM(7QM)
Fuel pumps 21QA(26QA) and 22QA(25QA)
Fuel pump-canisters 1QM(4QM) and 2QM(3QM)
Check valves 149QM(152QM), 150QM(151QM), 33QM(36QM), 34QM(35QM) and 37QM(38QM)
Engine-fuel-feed air-release-valves 86QM(87QM)
Scavenge jet-pumps 67QM(68QM) and 66QM(69QM)
Fuel-pump pressure-switches 23QA(24QA) and 27QA(28QA).

When it is in operation, each main pump supplies the fuel to:

its related engine
the recirculation cooling system (Ref. AMM D/O 28-16-00-00)
the crossfeed system (Ref. AMM D/O 28-23-00-00)
the refuel/defuel system (Ref. AMM D/O 28-25-00-00) (for pressure defuel)
the main transfer system (Ref. AMM D/O 28-26-00-00).

When it is in operation, each main pump supplies the fuel to:

its related engine
the crossfeed system (Ref. AMM D/O 28-23-00-00)
the refuel/defuel system (Ref. AMM D/O 28-25-00-00) (for pressure defuel).

Each wing tank has a closed area which is a collector cell. The collector cell is made between RIB1 and RIB2, the front and the rear spars and the top and bottom skins. Clack valves, in the bottom of RIB2, let the fuel go into the collector cells but do not let the fuel go out. The collector cells make sure that the main pumps are always fully in fuel during all flight manoeuvres. In the collector cells are:

two fuel pump canisters and their related fuel pump elements (which together make the main pumps)
two fuel strainers
a suction valve
two check valves.

The canisters 1QM(3QM) 2QM(4QM) are attached to the wing bottom skin and fully contain the fuel pump element. Each canister has two (upper) outlets that connect to:

the engine feed line
the transfer system (Ref. AMM D/O 28-26-00-00)
two (smaller) outlets that connect to the recirculation system (Ref. AMM D/O 28-16-00-00) and the fuel pump pressure switches 23QA(24QA), 27QA(28QA)
a vent valve installed on the top of the canister.

The engine feed outlet from each canister has an internal check valve. The check valves 149QM(151QM), 150QM(152QM) are installed in the transfer system outlet.
The vent valve is installed in a flametrap at the top of the canister. Gas or air that is removed from the fuel by the pump, is sent back to the fuel tank through the vent valve. The valve prevents fuel flow in the opposite direction and is opened by a probe in the related fuel pump.
When the fuel pump is not in operation the check valves prevent a flow of fuel back through the pump.

The canisters have a single (lower) inlet that connects to the fuel strainers 6QM(8QM), 5QM(7QM).
The canisters 1QM(3QM) 2QM(4QM) are attached to the wing bottom skin and fully contain the fuel pump element. Each canister has:

an upper outlet that connects to the engine feed line
an upper outlet that connects to a sequence valve
a (smaller) outlet that connects to the scavenge jet pumps 66QM(69QM), 67QM(68QM) and the fuel pump pressure switches 23QA(28QA), 27QA(24QA)
a vent valve installed on the top of the canister
a lower inlet that connects to the fuel strainers 6QM(8QM), 5QM(7QM).

The engine feed outlet from each canister has an internal check valve.
The check valves 33QM(36QM), 34QM(35QM) are in the line to the scavenge jet pumps.
The vent valve is installed in a flametrap at the top of the canister. Gas or air that is removed from the fuel by the pump, is sent back to the fuel tank through the vent valve. The valve prevents fuel flow in the opposite direction and is opened by a probe in the related fuel pump.
When the fuel pump is not in operation the check valves prevent a flow of fuel back through the pump.
Canisters 1QM(4QM) and 2QM(3QM) are attached to the wing bottom skin. These are connected to the fuel pump element. Each canister has two (upper) outlets that connect to:

The engine feed line
The transfer system (Ref. AMM D/O 28-26-00-00)
Two (smaller) outlets which are connected to the recirculation system (Ref. AMM D/O 28-16-00-00) and fuel-pump pressure-switches 23QA(24QA) and 27QA(28QA)
A vent valve installed on the top of the canister.

The engine feed outlet from each canister has an internal check valve. Check valves 149QM(151QM) and 150QM(152QM) are installed in the transfer system outlet.
Check valves 33QM(36QM), 34QM(35QM) and 37QM(38QM) are connected to the scavenge jet pumps.
The vent valve is installed in a flametrap at the top of the canister.
The gas or air that is removed from the fuel by the pump is released back to the fuel tank through the vent valve.
The valve prevents the fuel to flow in the opposite direction and is opened by a probe in the related fuel pump.
When the fuel pump is not in operation, the check valves prevent the flow of fuel back through the pump.

The canisters have one (lower) inlet that is connected to fuel strainers 6QM(7QM) and 5QM(8QM).
The canisters 84QM(85QM) are attached to the center tank bottom skin and fully contain the fuel pump element. Each canister has:

an upper outlet that connects to the engine feed line
a (smaller) outlet that connects to the scavenge jet pumps 89QM(90QM), and the fuel pump pressure switches 39QA(40QA)
a vent valve installed on the top of the canister
a lower inlet that connects to a fuel strainer.

The vent valve is installed in a flametrap at the top of the canister. Gas or air that is removed from the fuel by the pump, is sent back to the fuel tank through the vent valve. The valve prevents fuel flow in the opposite direction and is opened by a probe in the related fuel pump.
When the fuel pump is not in operation the check valves prevent a flow of fuel back through the pump.
The canister makes it possible to replace the fuel pump element when there is fuel in the fuel tank. When the fuel pump element is replaced, the internal check valve, the second check valve and a slide valve seal the canister.

The pressure switches 23QA(24QA), 27QA(28QA) monitor the output pressure of the fuel pumps. They are installed on the rear face of the wing rear spar. A banjo-connection and pressure pipe connect the pressure switch to the fuel pump. If the pressure from the main pump decreases to less than 0.41 bar (6 psi) the pressure switch:

puts on the amber FAULT light in the related main pump P/BSW
sends a signal to the Fuel Level Sensing Control Unit (FLSCU) (Ref. AMM D/O 28-46-00-00)
sends a signal to the ECAM system.

The pressure switches 23QA(28QA), 27QA(24QA) and 39QA(40QA) monitor the output pressure of the fuel pumps. They are installed on the rear face of the wing and center tank rear spar. A banjo-connection and pressure pipe connect the pressure switch to the fuel pump. If the pressure from the main pump decreases to less than 0.41 bar (6 psi) the pressure switch:

puts on the amber FAULT light in the related main pump P/BSW
sends a signal to the Fuel Level Sensing Control Unit (FLSCU) (Ref. AMM D/O 28-46-00-00)
sends a signal to the ECAM system.

The air release valve 86QM(87QM) releases the air caught in the engine fuel feed-line. The valve is installed at the high point between the pump and the LP valve (Ref. AMM D/O 28-24-00-00).

A suction valve is in the engine feed line in each of the collector cells. If all the main pumps fail the engines can use suction pressure to remove the fuel from the applicable tank through the suction valves.
The suction valve includes drain paths that transfer excess fluid into the collector cell from the tank which pressurizes the engine feed line.

Fuel Pump System - Cockpit Indications ** ON A/C NOT FOR ALL

Each fuel pump has a related control and indication circuit. These circuits have a P/BSW on the fuel control panel 40VU (which is part of the overhead panel). Each circuit also has an interface with the two System Data-Aquisition Concentrators (SDAC1 and SDAC2) (Ref. AMM D/O 31-54-00-00).

The P/BSWs are identified as:

L TK PUMP 1, 13QA
L TK PUMP 2, 15QA
R TK PUMP 1, 14QA
R TK PUMP 2, 16QA.

The P/BSWs are identified as:

L TK PUMP 1, 13QA
L TK PUMP 2, 15QA
R TK PUMP 1, 14QA
R TK PUMP 2, 16QA
CTR TK PUMP 1, 33QA
CTR TK PUMP 2, 34QA
CTR TK MODE SEL, 48QA.

The scavenge jet pumps 66QM(69QM), 67QM(68QM) are in the wing tank on the rear spar between RIB15 and RIB16.
Fuel can enter the surge tank (Ref. AMM D/O 28-11-00-00) through the venting system (Ref. AMM D/O 28-12-00-00) when this occurs, the scavenge jet pumps 66QM(69QM) move fuel to the rear intercell transfer valves 28QM(30QM) (Ref. AMM D/O 28-15-00-00).
The check valves 37QM(38QM) are in the fuel line between the surge tank and the related jet pump. They make sure that fuel cannot enter the surge tank through the related jet pump if the main pumps fail or are set to off.
The scavenge jet pumps 67QM(68QM) move fuel caught in the wing tank outer cell to the rear intercell transfer valve.
The scavenge jet pumps 89QM(90QM) are in the center tank on the rear spar. They move fuel caught in the center tank to the related center tank main pump inlet.

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4. Power Supply

Wing Tank Pump 2 and Center Tank Manual Control - Electrical Schematic ** ON A/C NOT FOR ALL

Wing Tank Pump 1 Emergency Operation - Electrical Schematic ** ON A/C NOT FOR ALL

Center Tank Pumps Automatic Control - Electrical Schematic ** ON A/C NOT FOR ALL

Wing Tank Pump 2 - Electrical Schematic ** ON A/C NOT FOR ALL

Wing Tank Pump 1 Emergency Operation - Electrical Schematic ** ON A/C NOT FOR ALL

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5. Interface

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

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6. Component Description

A. Fuel Pump Canister FIN: 1-QM FIN: 2-QM FIN: 3-QM FIN: 4-QM FIN: 84-QM FIN: 85-QM
1QM(3QM), 2QM(4QM)

Fuel Pump Canister and Strainer ** ON A/C NOT FOR ALL

Fuel Pump and Canister - Details ** ON A/C NOT FOR ALL

1QM(3QM), 2QM(4QM), 84QM(85QM)

Fuel Pump Canister and Strainer ** ON A/C NOT FOR ALL

Fuel Pump and Canister - Details ** ON A/C NOT FOR ALL

The fuel pump canister has:

a body
an outlet valve
a slide valve.

The body is hollow to contain the fuel pump. A mounting flange at the bottom of the body attaches the canister to the fuel tank. The fuel entrance to the canister is immediately above the mounting flange and a wire mesh strainer protects it. The slide valve closes to seal the fuel entrance to the canister when the fuel pump is removed. When the pump is installed it holds the slide valve in the open position.

The canister has two primary fuel outlets. One outlet contains the outlet valve and supplies the fuel to the engine feed pipe. The other outlet supplies the fuel to the jet pump.
A small opening in the side of the canister connects the pressure from the fuel pump to:

The related pressure switch
The recirculation system (Ref. AMM D/O 28-16-00-00).

The canister has two primary fuel outlets. One outlet contains the outlet valve and is the fuel supply to the engine feed pipe. The other outlet has a sequence valve. A small opening in the side of the canister connects the fuel pump to:

the pressure switch
the jet pumps.

The primary components of the outlet valve are:

the inlet body
the outlet body
the valve seat
the valve assembly.

The inlet body of the outlet valve connects to the fuel pump canister outlet and an O-ring seals it. The inlet body includes the valve seat which seals the poppet-type valve assembly (installed in the outlet body). The valve assembly has:

the spider assembly
the valve head
the spring.

The spider assembly has four legs with a spindle through the center. Each leg contains a steel ball which is held in place with a small spring. When the valve is closed, the four balls locate in a recess on the spindle.

When there is no fuel pressure, the spring holds the valve head against the valve seat. If the fuel pressure increases (but is less than a specified value) the force of the spring on the valve head (plus the force of the balls on the spindle) does not let the valve open. When the fuel pressure is more than 0.17 bar (2.5 psi) it pushes the valve head off its seat. The fuel then flows through the valve.

B. Fuel Pump Element
21QA(22QA) 25QA(26QA)

Fuel Pump and Canister - Details ** ON A/C NOT FOR ALL

21QA(22QA) 25QA(26QA) 37QA(38QA)

Fuel Pump and Canister - Details ** ON A/C NOT FOR ALL

The fuel pump element has:

a rotor assembly
an impeller assembly
an inducer assembly
a shaft
three thermal switches.

The pump element is assembled vertically. The rotor assembly is at the top. The impeller assembly is in the center and the inducer assembly is at the bottom. The shaft connects the three assemblies together.

The rotor assembly is a 3 phase 115VAC electrical motor. When energized it turns the shaft and the impeller and inducer assemblies. The inducer makes a suction that causes fuel to come through the impeller assembly. The impeller assembly pressurizes and pushes the fuel out of the canister.
The three thermal switches are in the electrical circuit of the fuel pump element. If the temperature of the pump element increases to more than 175 deg.C (347 deg.F) the switches operate. This causes the pump element to stop. It cannot operate again and must be replaced.

C. Fuel-Pump Pressure Switch
23QA(24QA), 27QA(28QA)

Main Pump Pressure Switches ** ON A/C NOT FOR ALL

23QA(24QA), 27QA(28QA), 39QA(40QA)

Main Pump Pressure Switches ** ON A/C NOT FOR ALL

The primary components of the fuel-pump pressure switch are the body and the banjo adapter. The body contains:

a flexible diaphragm
a switch mechanism
an electrical microswitch.

The flexible diaphragm isolates the switch mechanism and the microswitch from the fuel. When the fuel pressure increases to 0.55 bar (8 psi), the flexible diaphragm moves to operate the switch mechanism (which opens the contacts of the microswitch). When the fuel pressure decreases to 0.41 bar (6 psi), the flexible diaphragm moves (in the opposite direction) to operate the switch mechanism and close the contacts of the microswitch.

D. Scavenge Jet Pumps
66QM(69QM), 67QM(68QM), 89QM(90QM)

Jet Pump 66QM(69QM) 67QM(68QM) 89QM(90QM) ** ON A/C NOT FOR ALL

66QM(69QM), 67QM(68QM)

Jet Pump 66QM(69QM) 67QM(68QM) ** ON A/C NOT FOR ALL

The jet pump has:

a jet pump body
a jet adaptor assembly.

The jet pump body fully contains the jet adaptor assembly. The jet pump body has a flange at one end for installation to the tank rear spar. The jet pump body also has three threaded openings. These openings are as follows:

Z is the outlet from the jet pump
Y is the inlet from the fuel tank
X is the inlet from the related main pump.

The jet adaptor assembly has:

a Non-Return Valve (NRV)
a jet nozzle.

The NRV has a spring and a valve assembly. If the related main pump has a failure, or is set to off, the spring closes the NRV. Thus fuel cannot enter a main pump that is set to off.
When the related main pump is on, fuel goes into the jet pump through the opening X. The fuel moves through the NRV and the jet nozzle. The jet nozzle decreases the pressure and increases the velocity of the fuel that goes through it. This decrease in pressure and increase in velocity causes a suction pressure at the inlet Y. The fuel at the inlet Y is moved through the jet pump, with the fuel from the main pump, and out at the opening Z.

E. Check Valve
149QM(151QM), 150QM(152QM)

Fuel Pump and Canister - Details ** ON A/C NOT FOR ALL

33QM(36QM), 34QM(35QM), 37QM(38QM)

Check Valve 33QM(36QM), 34QM(35QM) and 37QM(38QM) ** ON A/C NOT FOR ALL

149QM(151QM), 150QM(152QM), 33QM(36QM), 34QM(35QM) and 37QM(38QM)

Fuel Pump and Canister - Details ** ON A/C NOT FOR ALL

Check Valve 33QM(36QM), 34QM(35QM) and 37QM(38QM) ** ON A/C NOT FOR ALL

The primary components of the check valve are:

a (flanged) body
a flap valve
a valve seat.

The valve body is connected to the fuel pump canister (transfer system) outlet. The joint is sealed with an O-ring. A spring holds the flap valve against the valve seat in the body.

The check valve has:

two half bodies (inlet and outlet)
a spindle and a special washer
a spring
a spindle guide.

The primary components of check valves 149QM(151QM) and 150QM(152QM) are:

A (flanged) body
A flap valve
A valve seat.

Two half bodies (inlet and outlet)
A spindle and a special washer
A spring
A spindle guide.

Three countersunk bolts and three screws connect the two half bodies. An O-ring seal, between the two half bodies, stops the fuel leaks. The special washer, spindle, spring and spindle guide are installed in the two half bodies to make the valve. The shank of the spindle goes through the spindle guide. The spring is installed between the spindle and the spindle guide to keep the valve in the closed position.
When the fuel pressure in the main pump is more than a specified value, check valves 149QM(151QM) and 150QM(152QM) opens. This lets the fuel to move to the main transfer system.
When the fuel pressure decreases (to less than a specified value), the spring pushes the flap against its seat and stops the fuel flow. This prevents the flow of fuel into the main pump from the main transfer system.
Three countersunk bolts and three screws connect the two half bodies. An O-ring seal, between the two half bodies, stops fuel leaks. The special washer, the spindle, the spring and the spindle guide are installed in the two half bodies to make the valve. The shank of the spindle goes through the spindle guide. The spring is installed between the spindle and the spindle guide to keep the valve in the closed position.

F. Sequence Valve

Sequence Valve ** ON A/C NOT FOR ALL

The sequence valve has:

a valve body
a poppet valve
a spring
a valve guide
an upper and a lower cover.

The valve body contains the poppet valve, the spring and the valve guide. The poppet valve closes the valve body inlet and a spring keeps it in this position. The valve guide is in the top end of the valve body. The shank of the poppet valve goes through the valve guide, this makes sure that the valve is kept in position during its operation.
The valve body has four openings to let the fuel out and back into its related fuel tank.
The covers prevent damage to the valve and make sure that the fuel enters the tank smoothly.
When the fuel pressure at the valve inlet is more than 1.74 bar (25.2 psi), the valve opens. The fuel then moves from the valve inlet back into its related fuel tank. When the fuel pressure at the valve inlet decreases to a specified value, the valve closes.

G. Air Release Valve 86QM(87QM)

Air Release Valve

The air release valve has:

a valve body
a diaphragm and vent valve assembly
a rubber check valve
an annular float.

The body of the air release valve has a mounting flange at the bottom and the rubber check valve at the top. Internally the valve has three chambers, which are:

a vent chamber
a diaphragm chamber
a float chamber.

The float chamber contains an annular float. The openings in the bottom of the chamber let in the fuel and the air. A small opening at the top of the float chamber connects to the diaphragm-chamber. The vent valve (attached to the center of the diaphragm) closes the vent port between the float chamber and the vent chamber. The valve has these conditions of operation:

the stable or suction condition
the air in fuel condition
the bled-of-air condition.

Stable or suction condition.
When the pressure in the valve is equal to (or less than) the pressure in the fuel tank, the rubber check valve closes (to seal the valve).

Air-in-fuel condition.
If air (which is caught in the fuel pipe) goes into the float chamber, the float falls. This opens the opening to the diaphragm chamber. During the fuel pump operation this air becomes pressurized which causes:
(1) the diaphragm/vent valve assembly to move to the open position
(2) the rubber check valve to open
(3) the air to bleed from the valve (and thus from the fuel pipe).

Bled-of-air condition.
When the fuel goes into the float chamber:
(1) the float lifts and seals the opening to the diaphragm chamber
(2) the diaphragm/vent valve assembly moves to the closed position
(3) the rubber check valve closes to seal the valve.

H. Ground Fault Interrupter 69QA(70QA)

GFI - Component Location ** ON A/C NOT FOR ALL

The primary components of the Ground Fault Interrupter (GFI) are:

a 3 Pole Single Throw relay and
an auxiliary Single Pole Double Throw contact.

Operational functions of the GFI are as follows:

If a ground fault occurs in the load or on the wiring, downstream of the GFI:
the GFI micro-contactor will operate to isolate the load and ground fault from the power supply
the GFI will trip and the RESET P/BSW's metallic shaft will be visible.

The GFI will operate to close the main contacts when the load is selected to ON (relay coil supplied with 28 VDC or 100 VDC). When the load is selected to OFF the main contacts of the GFI will open.
When the RESET P/BSW is in the normal position, the RESET P/BSW's metallic shaft is not visible.

The GFI micro-contactor can be tripped when the auto-test P/BSW is pushed. If the RESET P/BSW is in the normal position, the GFI function is defective. The GFI micro-contactor can be unlatched when the RESET P/BSW is pushed. The pins connection A1 and C1 must be energized to perform the auto-test of the GFI.

The GFI will trip when the:
maximum differential current is between 1.35 A and 1.65A
detection time of the GFI is between 2.9 and 3.1 milli seconds
total reaction time of the GFI (detection time and the opening time of the contactor to isolate the system) is more than 20 milli seconds.

** ON A/C NOT FOR ALL

7. Operation/Control and Indicating

Main Fuel Pump Scavenge System ** ON A/C NOT FOR ALL

Wing Tank Pump 2 and Center Tank Manual Control - Electrical Schematic ** ON A/C NOT FOR ALL

Wing Tank Pump 1 Emergency Operation - Electrical Schematic ** ON A/C NOT FOR ALL

Center Tank Pumps Automatic Control - Electrical Schematic ** ON A/C NOT FOR ALL

Wing Tank Pump 2 - Electrical Schematic ** ON A/C NOT FOR ALL

Wing Tank Pump 1 Emergency Operation - Electrical Schematic ** ON A/C NOT FOR ALL

The main fuel pump system is manually controlled. For the system to operate it is necessary to:
The wing tank pumps of the main fuel pump system are manually controlled. The FLSCUs normally control the center tank pumps automatically. For the system to operate it is necessary to:

energize the 115AC BUS (101XP), (103XP), (202XP) and (204XP), and the 28VDC BUS (101PP), (103PP), (202PP), (204PP) and (401PP)
close the circuit breakers 1QA, 2QA, 3QA, 4QA, 7QA, 8QA, 9QA, 10QA, 11QA, 12QA and 55QA.

The main fuel pump system has four main pumps. The main fuel pump system is divided into two sub-systems (LH/RH). Each sub-system has two main pumps that supply fuel to their related engine. The circuit for each sub-system contains (and connects to) the same type of equipment. As the other sub-system is the same, only the operation of the No. 1 sub-system/circuit (LH) is given here.

energize the 115AC BUS (101XP), (103XP), (202XP) and (204XP), and the 28VDC BUS (101PP), (103PP), (202PP), (204PP) and (401PP)
close the circuit breakers 1QA, 2QA, 3QA, 4QA, 7QA, 8QA, 9QA, 10QA, 11QA, 12QA, 29QA, 30QA, 31QA, 32QA, 47QA and 55QA.

The main fuel pump system has six main pumps. The main fuel pump system is divided into two sub-systems (LH/RH). Each sub-system has three main pumps that supply fuel to their related engine. The circuit for each sub-system contains (and connects to) the same type of equipment. As the other sub-system is the same, only the operation of the No. 1 sub-system/circuit (LH) is given here.

A. Operation

The L TK PUMPS 1 and 2 P/BSWs are usually set to on together. The main pumps then operate continuously. If one main pump has a failure (or is set to OFF), the other main pump will continue to supply fuel to its related engine. When you set the L TK PUMP 1 P/BSW 13QA to ON, it connects a 28VDC supply to the contactor 17QA (No. 1 fuel pump contactor-control). The contactor connects a 115VAC supply to energize the fuel pump 21QA.

In normal conditions the two pumps in the wing tank or the related pump in the center tank supply an engine. But, one pump can supply the necessary fuel for an engine.

The fuel supply to one engine is controlled independently of the other. Thus, the wing tank pumps can supply the fuel for one of the engines and the opposite center tank pump can supply the other engine.

The center tank pumps are set to give a higher pressure of fuel than the related wing tank pumps. A sequence valve (installed on each wing tank pump canister) reduces the output pressure of the related wing tank pump. When all the pumps operate, the center tank pump will supply fuel to its related engine.

When the wing tank pumps are set to ON, the pumps will operate continuously during the flight until switched off manually.

The center tank pumps have two modes of operation, manual and automatic. The MODE SEL P/BSW (48QA), on the FUEL panel (40VU), controls these modes of operation.
In manual mode (MODE SEL P/BSW released out), the operation of the center tank pumps is controlled by the CTR TK PUMPS 1 and 2 P/BSWs (33QA and 34QA).
In automatic mode (MODE SEL P/BSW pushed in), and with the CTR TK PUMPS 1 and 2 P/BSWs set to ON:

the center tank pumps are set to on and off automatically during specified flight phases
the center tank pumps will supply fuel to the engines, as required, when the fuel is at specified levels (Ref. AMM D/O 28-46-00-00).

At engine start-up, the automatic fuel feed system operates as follows:

a signal from the interface units (1KS1 and 1KS2) energizes the center tank control relays (51QA, 52QA)
the AUTO CTL relays (41QA, 42QA) are de-energized
if the center tank LOW LVL sensors are wet with fuel the two center tank pumps operate
two minutes after the first engine reaches idle speed, the center tank pumps stop
if the second engine is started during the two minutes, the center tank pumps will operate for two more minutes. They will operate for two more minutes from when the second engine reaches idle speed and then stop
if the second engine is started after the two minutes are over, the center tank pumps will operate again for two minutes. They will operate from the time that the second engine reaches idle speed
the position of the slats now controls the operation of the center tank pumps
the center tank pumps will not operate again until the slats are retracted
until then the wing tank pumps supply fuel to the engines.

After take-off, the automatic fuel feed system operates as follows:

the AUTO CTL relays (41QA and 42QA) de-energize when the slats retract
the center tank pump control Ground Fault Interrupters (GFIs) (69QA and 70QA) energize and the center tank pumps are given signals to operate, independently of each other
a center tank pump will stop when the two FULL LVL sensors in the related wing tank are wet. The pump will not operate again until at least one UNDERFULL LVL sensor in the related wing tank is dry. The related center tank LOW LVL sensor must also be wet for the pump to restart
a signal is given to the time delay relays (45QA and 46QA) when a center tank LOW LVL sensor becomes dry. When the LOW LVL sensor has been dry for five minutes, the related center tank pump is latched off
the latch is released and the related pump(s) come on when MANUAL mode is selected or when the refuel panel access door is opened
FAULT INHIBIT relays do not let the FAULT annunciators come ON during the five minute cycle
when a center tank pump stops, an engine is supplied with fuel from the related wing tank pumps.

In the electrical smoke configuration (Ref. AMM D/O 24-24-00-00) the contactor 17QA is de-energized. The L (R) TK PUMP 1 P/BSW then connects a 28VDC supply to the contactor 53QA (No. 1 fuel pump emergency contactor-control). The contactor 53QA connects a 115VAC supply to energize the fuel pump 21QA (22QA).

The pumps get their fuel supply from the lowest part of the collector cell. When they are in operation each pump gives three outputs. One output is to the engine feed pipe, one to the fuel recirculation cooling system (Ref. AMM D/O 28-16-00-00) and the other to the main transfer system (Ref. AMM D/O 28-26-00-00).

The pumps get their fuel supply from the lowest part of the collector cell. When they are in operation each pump gives two outputs. One output is to the engine feed pipe, one to the related scavenge jet pump.

B. Cockpit Indications

If specified failures or system configurations occur in the main fuel pump system:

the Flight Warning Computer (FWC) (Ref. AMM D/O 31-52-00-00) gives an aural and visual warning
the ECAM shows a failure message on the EWD, and the FUEL page on the SD.

If necessary, a procedure to correct the effects of the failure is also given with the warning message.

(1) EWD Messages
The warning messages given are:

(a) FUEL L TK PUMP 1 LO PR
The No. 1 main pump is set to on, but low pressure has occurred (equivalent warning messages are given for the R TK PUMP 1).

(b) FUEL L TK PUMP 2 LO PR
The No. 2 main pump is set to on, but low pressure has occurred (equivalent warning messages are given for the R TK PUMP 2).

(c) FUEL L TK PUMPS 1+2 LO PR
Both the fuel pumps in the LH wing are set to on, but low pressure has occurred (an equivalent warning message is given for the R TK PUMPS 1+2).

(2) EWD Messages
The warning messages given are:

(a) FUEL L TK PUMP 1 LO PR
The No. 1 main pump is set to on, but low pressure has occurred (equivalent warning messages are given for the R TK PUMP 1).

(b) FUEL L TK PUMP 2 LO PR
The No. 2 main pump is set to on, but low pressure has occurred (equivalent warning messages are given for the R TK PUMP 2).

(c) FUEL L TK PUMPS 1+2 LO PR
Both the fuel pumps in the LH wing are set to on, but low pressure has occurred (an equivalent warning message is given for the R TK PUMPS 1+2).

(d) FUEL CTR TK PUMP 1 LO PR
The center tank pump 1 (LH) is set to on, but low pressure has occurred (Equivalent warning message for center tank pump 2 (RH)).

(e) FUEL CTR TK PUMPS LO PR
The center tank pumps 1 and 2 are set to on, but low pressure has occurred.

(f) FUEL CTR TK PUMPS OFF
The center tank pumps are set to OFF, but no failure has occurred.

(g) FUEL AUTO FEED FAULT
The fuel pumps are set to on with the fuel condition as follows:

left or right wing tank contains less than 5000 kg (11023 lb) of fuel
center tank contains more than 250 kg (551 lb) of fuel.

The center tank pumps do not stop after the slats are extended.
The center tank pumps do not stop 5 minutes after the related low level sensors are dry.

(3) SD (Fuel Page) Indications

ECAM (FUEL Page) Display - Main Fuel Pump System Indication ** ON A/C NOT FOR ALL

ECAM (FUEL page) Display - Main Fuel-Pump-System Indication ** ON A/C NOT FOR ALL

(4) SD (Fuel Page) Indications

ECAM (FUEL Page) Display - Main Fuel Pump System Indication ** ON A/C NOT FOR ALL

(5) Fuel Control Panel 40VU

Fuel Pump System - Cockpit Indications ** ON A/C NOT FOR ALL

(a) Each fuel pump P/BSW shows:

OFF (white) when the fuel pump is not set to on
FAULT (amber) if a failure occurs (pump low pressure).

(6) Fuel Control Panel 40VU

Fuel Pump System - Cockpit Indications ** ON A/C NOT FOR ALL

(a) Each fuel pump P/BSW shows:

OFF (white) when the fuel pump is not set to on
FAULT (amber) if a failure occurs (pump low pressure).

(b) The MODE SEL P/BSW shows:

MAN (white) when the center tank pumps are in manual control
FAULT (amber) if a failure has occurred whilst the center tank pumps are in auto mode.

** ON A/C NOT FOR ALL

8. BITE Test
Not applicable

[Rev.10 from 2021] 2026.04.01 07:15:44 UTC