FUEL SYSTEM COMPONENT LOCATION A318/A319/A320/A321
SYSTEM OVERVIEW
The A318, A319 and A320 have the same fuel system design.
The fuel tanks are in the center fuselage area and the wings. The center
tank is a part of the center wing box. The wing tanks are divided into
inner cells and outer cells. To have less structural load on the wings, the
fuel in the outer cells is not used until the fuel load in the inner cells
decreases to a low level.
Two fuel pumps are installed in the center tank and two other fuel pumps
are installed in each wing tank inner cell. Fuel is supplied to the engines
from the center tank first. When the center tank is empty, fuel is supplied
from the wing inner cells.
There is no direct feed from the outer cells to the engines. Two inter cell
transfer valves are used to transfer fuel from the outer cells to the inner
cells when the fuel quantity gets to the low level.
Two engine Low Pressure (LP) valves are installed to stop the fuel supply
to the engines. The LP valve is closed when its related engine stops or
when the FIRE pushbutton is released.
A cross feed valve is used to connect or isolate the left and right sides.
With this valve, fuel can be supplied to one engine or the other from all
available fuel pumps. On the ground, the cross feed valve is used to
transfer fuel from tank to tank.
The fuel system also supplies fuel to the APU directly from the left side.
The APU LP valve is installed to stop the fuel supply to the APU. It
closes when the APU stops or when the APU FIRE pushbutton is released.
A321
The A321 fuel tanks are in the center fuselage area and the wings.
Like the A318/A319/A320, the center tank is part of the center wing
box but with the difference that the wing tanks are not divided. The
tanks are simply known as left and right wing tanks.
Two fuel pumps are installed in each wing tank. Fuel is supplied to
the engines from the wing tanks only. While the fuel level in the wing
decreases, the center tank fuel is transferred to the wing tanks until
the center tank is empty.
Transfer valves control the fuel transfer from the center tank to the
wing tanks. The transfer valves supply pressure for two jet pumps.
These pumps are installed in the center tank and they transfer the fuel
from the center tank to the wing tanks.
Two engine Low Pressure (LP) valves are installed to stop the fuel
supply to the engines. The LP valve is closed when its related engine
stops or when the FIRE pushbutton is released.
A cross feed valve is used to connect or isolate the left and right sides.
With this valve, fuel can be supplied to one engine or the other from
all available fuel pumps. On the ground, the cross feed valve is used
to transfer fuel from tank to tank.
The fuel system also supplies fuel to the APU directly from the left
side. The APU LP valve is installed to stop the fuel supply to the APU.
It closes when the APU stops or when the APU FIRE pushbutton is
released.
COMPONENT LOCATION
The wing fuel feed pumps are replaced from the wing lower surface. The
center tank pumps are replaced through access panels in the belly fairing.
The water drain valves let you remove water, which could collect in
quantities sufficient to cause malfunction to the engines.
The manual Magnetic Level Indicators are used to calculate the tank fuel
quantities if a failure has an unwanted effect on the Fuel Quantity
Indicating System.
REFUEL/DEFUEL COUPLING AND REFUEL VALVE
The Refuel/Defuel coupling is on the lower surface of the RH wing,
near the leading edge. The Refuel/Defuel coupling shown is the
optional one on the LH side.
There is one refuel valve on each tank. Each of the three refuel valves
has a manual plunger. When pushed, the plunger holds the valve open
if an electrical failure of the valve occurs during refueling.
