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P/N 140-590032-0007
Revision A4: Sep, 2010
Section III Sub-section 3
FUEL SYSTEM
Pilot’s Operating Manual
FUEL PRESSURE SWITCH
A pressure switch in each fuel line, upstream of the engine driven pumps, monitors fuel pressure.
The pressure switch illuminates the FUEL 1 LO PRESS or FUEL 2 LO PRESS annunciators on the
overhead roof when the pressure drops below 6.5 (
±
.5) psi and extinguishes the annunciators when
the fuel pressure increases. The FUEL repeater annunciator, on the MWS panel, will also illuminate to
direct the flight crew’s attention to the overhead roof panel.
LOW PRESSURE COCKS and LEVERS
A low pressure (LP) fuel cock valve, one in each engine supply line, isolates the engine fuel feed pipes
from the wing tanks and provides system shutdown for engine fire control procedures. The LP COCK
levers, one for each engine, are located on the center control pedestal and mechanically open and close
the LP fuel cock valves when moved up or down respectively.
To operate, lift a hinged guard installed above the control levers before the levers are moved to the
closed (down) position. The LP COCK levers also incorporate a spring loaded knob to lock the lever in
either the open or closed positions.
NOTE: Closing the No. 1 LP COCK lever will also close the fuel supply to the APU (if installed).
HIGH PRESSURE COCKS and LEVERS
The HP COCK levers, one for each engine, are located above the LP COCK levers on the center control
pedestal and open and close the manual fuel shutoff valve inside the fuel control unit.
Each shutoff valve opens or closes when the associated HP COCK control lever is moved up or down
respectively. The HP COCK levers incorporate a spring loaded knob to lock the lever in either the open
or closed positions. Opening the HP COCK lever during the engine start cycle initiates ignition.
Fuel To Engine Cutoff
Placing the HP COCK in the closed position, closes the manual fuel shutoff valve, moves the thrust lever
to the idle position and shuts off fuel to the engine should an engine fire occur. The hydraulic supply
valve is also closed by this action as a fire control measure.
