King Air C90GTi, Pilot Training Manual

Page: 125 / 557

FUEL SYSTEM
OPERATION
Fuel flow from each wing tank system and
nacelle tank is automatic without pilot ac-
tion (Figure 5-6). The wing tanks g ravity
feed into the center section tank through a
l i n e ex t e n d i n g f r o m t h e a f t i n b o a r d w i n g
tank to be outboard side of the center sec-
tion tank. A flapper-type check valve in the
e n d o f t h e g r av i t y f e e d l i n e p r eve n t s a ny
backflow of fuel into the wing tanks.
The fuel pressure required to operate the en-
gine is provided by an engine-driven fuel
pump mounted in conjunction with the fuel
control unit on the accessor y case. Fuel is
pumped to the high pressure fuel pump by an
electrically-driven boost pump submerged in
the nacelle tank.
T h e s u p p ly l i n e f r o m t h e n a c e l l e t a n k i s
routed from the outboard side of the nacelle
tank, forward to the engine-driven fuel pump
through a motored f irewall shutoff valve in-
stalled in the fuel line immediately behind
the engine f irewall.
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
5-8
FOR TRAINING PURPOSES ONLY
5
FUEL
SY
STEM
FUEL FLOW
TRANSMITTER
FUEL HEATER
TO ENGINE
FUEL OUTLET
NOZZLES
FUEL MANIFOLD
DUMP-VALVE
ENGINE FUEL
CONTROL UNIT
ENGINE-DRIVEN
FUEL PUMP
FUEL PRESSURE
SWITCH
FIREWALL SHUTOFF VALVE
FUEL PRESSURE
ANNUNCIATOR
THERMAL-RELIEF BYPASS
SUBMERGED BOOST
PUMP AND DRAIN
RAM SCOOP VENT
SIPHON
BREAK LINE
HEATED VENT
TRANSFER WARNING
LIGHT SWITCH
TRANSFER PUMP
AND DRAIN
FUEL TRANSFER
PUMP RESTRICTOR
WHEEL
WELL
L
SUPPLY
TRANSFER
BOOST (LOW) PRESSURE
HIGH PRESSURE
FUEL CONTROL
UNIT PURGE
FUEL FILTER
(FIREWALL)
AND DRAIN
CROSSFEED
VALVE
TO RIGHT
ENGINE
*
FILLER CAP
QUANTITY
LBS. 100
0
2
4
6 8
10
12
14
QUANTITY
INDICATOR
DRAIN
VALVE
LEGEND
NOTE:
RIGHT SYSTEM IS IDENTICAL TO LEFT SYSTEM EXCEPT THAT THE LATTER
CONTAINS THE CROSSFEED VALVE. IT SHOULD ALSO BE NOTED THAT THE
PURGE VALVE AND FUEL LINE ARE ON THE INBOARD SIDE OF THE
NACELLE AND THAT THERE IS A THERMAL RELIEF VALVE AND LINE FROM THE
CROSSFEED LINE IN THE RIGHT FUEL SYSTEM.
* VALVE HAS HOLES FOR FLOW OUT AT REDUCED RATE. 28 GALLONS WILL NOT
GRAVITY-FEED TO NACELLE.
Figure 5-6. Fuel Flow Diagram