Beechcraft C-12C Operator And Technical Reference Manual page 73

Both switches
crossfeed operation.
(4) Fuel Transfer Control Switches.
switches, placarded AUX TRANSFER OVERRIDE /
AUTO C D T1 and AUX XFER OVRD / AUTO
the fuel management panel control operation of the
fuel transfer pumps. During normal operation, both
switches are in AUTO, which allows the pump to be
automatically actuated by fuel flow to the engine. If
either transfer system fails to operate, the fault
condition is indicated by two illuminated MASTER
CAUTION lights on the glareshield and a steady
illuminated yellow #1 or #2 NO FUEL XFR light on the
caution annunciator panel.
(5) Fuel Crossfeed
crossfeed valve is controlled by a 3-position switch
located on the fuel management panel, placarded
CROSSFEED OFF. Under normal flight conditions the
switch is left in the OFF position. During single engine
operation, it may become necessary to supply fuel to
the operative engine from the fuel system on the
opposite side. The crossfeed system is placarded for
fuel selection with a simplified diagram on the
overhead fuel control panel. Place the standby fuel
pump switches in the off position when crossfeeding.
A lever lock switch, placarded CROSSFEED, is moved
from the center OFF position to the left or to the right,
depending on direction of fuel flow, to energize the
crossfeed valve and energize the standby pump on the
side from which crossfeed is desired.
crossfeed operation, auxiliary tank fuel will not
crossfeed if the FUEL FIREWALL valve is closed.
When the crossfeed mode is energized, a green FUEL
CROSSFEED light on the caution/advisory panel,
Figure 2-17, will illuminate.
operation is described in Chapter 9. The crossfeed
valve is protected by a 5-ampere circuit breaker,
placarded CROSSFEED VALVE, located on the
overhead circuit breaker panel.
g. Firewall Shutoff Valves.
Do not use the fuel firewall shutoff valve to
shut down an engine, except in an
emergency. The
pressure fuel pump obtains essential
lubrication from fuel flow. When an engine
is operating, this pump may be severely
damaged (while cavitating) if the firewall
valve is closed before the condition lever is
moved to the FUEL CUTOFF position.
NOTE
shall be off during
Switch. The
Crossfeed system
CAUTION
engine-driven high-
The fuel system incorporates a fuel line shutoff
valve on each engine firewall.
valves close automatically when the fire extinguisher T
handles on the instrument panel are pulled out. The
firewall shutoff valves receive electrical power from the
Two
main buses and also from the battery bus, which is
connected directly to the battery.
T2 , on
protected by circuit breakers, placarded FIREWALL
VALVE #1 or #2, on the overhead circuit breaker
panel, Figure 2-16, and FIREWALL SHUTOFF #1 or
#2 on the hot battery bus circuit breaker board.
h. Fuel Tank Sump Drains.
wrench is provided in the aircraft loose tools to simplify
draining a small amount of fuel from the sump drain.
(1) There are five sump drains and one filter
fuel drain in each wing.
locations.
Table 2-4. Drains and Their Locations
DRAIN
Leading edge tank
Integral tank
Firewall fuel filter
Sump strainer
During
Gravity feed line
Aux tank
(2) An additional drain for the extended
range fuel system line extends through the bottom of
the wing center section adjacent to the fuselage.
Anytime the extended range system is in use, a part of
the preflight inspection would consist of draining a
small amount of fuel from this drain to check for fuel
contamination. Whenever the extended range system
is removed from the aircraft and the fuel line is capped
off in the fuselage, the remaining fuel in the line shall
be drained.
(3) Each ferry fuel tank has a 10-foot
1/4-inch flex hose with a quick drain installed in the aft
end. When the ferry fuel system is in use, the preflight
inspection also includes draining a small amount of
fuel from these drains to drain off any moisture that
may have been inadvertently introduced into the tanks.
Place the aft end of the hoses out through the cabin
TM 1-1510-218-10
The firewall shutoff
The valves are
A sump drain
Refer to Table 2-4 for their
LOCATION
Outboard of nacelle
underside of wing
Underside of wing forward
of aileron
Underside of cowling
forward of firewall
Bottom center of nacelle
forward of wheel well
Aft of wheel well
At wing root just forward of
the flap
2-57