R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499,
 Defuel The main fuel pump system (Ref. 28-21-00) is used to defuel the aircraft. The pumps remove the fuel from the related fuel tank and supply it to the refuel/defuel coupling. The defuel/transfer valve and the crossfeed valve (Ref. 28-23-00) must be open to defuel the aircraft.
 **ON A/C 301-399,
 Defuel The main fuel pump system (Ref. 28-21-00) is used to defuel the aircraft. The pumps remove the fuel from the related wing tank and supply it to the refuel/defuel coupling. The defuel/transfer valve and the crossfeed valve (Ref. 28-23-00) must be open to defuel the aircraft. To defuel the center (transfer) tank the main transfer
 1EFF : ALL 1 28-00-00Page 21 1 1 Aug 01/05 1 1 1CES 1 system (Ref. 28-26-00) must be used to move the fuel to the related wing tank.

 (6) Main Transfer System (Ref. 28-26-00) The main transfer system controls the flow of fuel from the center (transfer) tank to the two wing tanks. The system uses jet pumps that are supplied with fuel from the main fuel pump system (Ref. 28-21-00). The fuel goes through a nozzle in the jet pump to produce a suction. This suction removes the fuel from the center (transfer) tank and then moves it to the related wing tank. The main transfer system also uses gravity to move the fuel from the center (transfer) tank to the wing tanks. Gravity movement of fuel occurs when the fuel level in the center (transfer) tank is higher than that in the wing tanks. The Fuel Level Sensing Control Units (FLSCUs) automatically control the transfer system, but if necessary, the crew can manually control it from the cockpit.
 **ON A/C ALL
 (7) APU LP Fuel Shut Off (Ref. 28-29-00) The APU LP fuel shut off valve controls the fuel supply from the fuel tank to the APU. When necessary the valve isolates the APU from its fuel supply. The operation of the APU LP valve is controlled by:
 -
the APU MASTER SW (Ref. 49-42-00)

 -
the APU SHUT OFF switch (Ref. 49-62-00)

 -
the APU FIRE switch (Ref. 26-13-00).

 C. Indicating (Ref. 28-40-00)
 The indicating system has:
 -
the Fuel Quantity Indicating (FQI) system, which gives separate and total fuel quantity indications

 -
the Magnetic Level Indicators (MLI), a secondary system used to estimate the fuel quantity when the aircraft is on the ground

 -
the tank level sensing, which gives indications and warnings when the fuel is at specified levels

 -
the fuel temperature measurement, which gives continuous temperature indications and warnings when the fuel temperature is at specified levels.

 (1) Quantity Indicating (Ref. 28-42-00) The FQI system measures the total quantity of fuel in the range unusable to overflow. It gives indications for these fuel tanks:
 -
the LH and RH wing tanks

 -
the center tank.

 1EFF : ALL 1 28-00-00Page 22 1 1 Aug 01/05R 1 1 1CES 1

 The system has FQI probes that the FQIC monitors. The FQIC uses signal conditioning to calculate the quantity of fuel in each fuel tank. The FQIC gives fuel quantity data to:
 -
the Engine/Warning Display (EWD) (Ref. 31-66-00) and the System Display (SD) FUEL Page, which together make up the ECAM

 -
the multi-tank fuel quantity indicator (6QT)

 -
the fuel quantity preselector (5QT).
 The FQIC uses the fuel quantity data to control an automatic refuel
 operation to below high level (Ref. 28-46-00).

R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499,
 The FQIC monitors a diode within the probes 22QT1(22QT2) and 33QT1(33QT2) in the wing tanks. The FQIC uses signal conditioning to calculate the temperature of the fuel adjacent to these diodes. The fuel temperature is displayed on the System Display (SD) FUEL Page.
 **ON A/C 301-399,
 Two temperature sensors are installed on one of the FQI probes in each wing tank. The FQIC uses signal conditioning to calculate the temperature of the fuel adjacent to these sensors. The fuel temperature is displayed on the System Display (SD) FUEL Page.
 **ON A/C ALL
 (2)
 Magnetic Level Indicators (Ref. 28-43-00)

 The MLIs are a secondary direct-reading system used to calculate the fuel quantity in the LH wing, RH wing and center tanks (when the A/C is on the ground). It is not necessary to have electrical power to use the indicators. The combined MLI indications, aircraft attitude and fuel relative density, are converted with tables (Ref. 12-11-28) to give the amount of fuel in each tank.

 (3)
 Tank Level Sensing (Ref. 28-46-00) The tank level sensing system monitors the level of fuel in:

 -
　
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