Operation Manual Part 2

Aerosoft – Digital Aviation
CRJ-70 & CRJ-900
AOM PART 2
Systems Description
VOL
5
5-1-72
26-Jul-2017
The engines are supplied with fuel from the so-called side collective tanks. These two tanks are structural part
of the central tank but are separate tanks though. To prevent fuel starvation during manoeuvring, the
collective tanks are continuously filled up by the monitoring computer system. Boost pumps support fuel feed
to the engines in case of a pressure drop in the fuel line. The boost pumps are normally on standby but as soon
as a pressure drop is sensed, the boost pumps are activated. During engine start the boost pumps are
activated as well, independent of the pressure in the fuel line.
The APU is supplied from the left collective tank. The APU fuel pump ensures sufficient pressure on the fuel
line to the APU. Activating the APU also activates the APU fuel pump.
FUEL QUANTITY GAUGING
Several probes in the wing center and collective tanks determine the amount of fuel in the respective tank,
fuel temperature and fuel density. These signals are processed by a computer system to correct errors due to
wing deflection, or density changes. The resulting fuel quantities, temperature and amount of used fuel are
displayed on the EICAS.