737 Flight Crew Operations Manual
Fuel -
System Description
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D6-27370-866-EGP 12.20.3
Fuel Shutoff Valves
Spar fuel shutoff valves are located at the engine–mounting wing stations. The
valves are DC motor operated from the hot battery bus. The engine fuel shutoff
valves are fuel actuated, solenoid controlled valves powered from the battery bus.
Both the spar fuel shutoff valve and the engine fuel shutoff valve close whenever
their respective engine fire switch is pulled or engine start lever is placed to
CUTOFF.
Center Tank Fuel Scavenge Jet Pump
With the main tank fuel pump No. 1 FWD Switch ON, the center tank fuel
scavenge jet pump operates automatically to transfer any remaining center tank
fuel to main tank No. 1. Fuel transfer begins when main tank No. 1 quantity is
about one-half. Once the fuel scavenge process begins, it continues for the
remainder of the flight.
Fuel Temperature
The FUEL TEMP indicator located on the fuel control panel displays fuel
temperature. A sensor in main tank No. 1 allows monitoring of fuel temperature.
The temperature indicating system uses AC electrical power.
APU Fuel Feed
When AC fuel pumps are operating, fuel for the APU is supplied from the left side
of the fuel manifold. If the AC fuel pumps are not operating, fuel is suction fed
from main tank No. 1.
Fuel Quantity Indication
The fuel quantity indication system calculates the usable fuel quantity in each
tank. The fuel quantity in each tank is displayed on the upper display unit and on
the fueling station panel.
Fueling/Defueling/Ground Transfer
Rapid fueling and defueling is accomplished at the single–point pressure fueling
station in the right wing. The fueling station is also used for the ground transfer of
fuel between tanks.
The manual defueling valve, located outboard of engine No. 2, interconnects the
engine feed system and the fueling station. It is opened for defueling and tank to
tank transfer operations.
A shutoff system is used during fueling to automatically close the fueling valve in
each fuel tank when the tank is full.
June 5, 2009
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