737 MAX Flight Crew Operations Manual
Fuel -
System Description
MN-FLT-OH-201
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 high-pressure
shutoff valves are fuel actuated, solenoid controlled valves powered from the
battery bus. Both the spar fuel shutoff valve and the engine high-pressure 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 indicating system calculates the usable fuel quantity in each
tank. The fuel quantity for each tank, and the total fuel quantity are displayed on
the main displays in the flight deck. During refuel operations, each tank has its
own refuel panel indicator fuel quantity display. In flight, each tank fuel quantity
could show higher or lower than the actual fuel quantity by up to 2.5% due to
system accuracy constraints.
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.
March 1, 2021
