Eagle ICA-D212-725, Instructions Manual

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ICA-D212-725 (28)
Page 6 of 48
CHAPTER 28 – FUEL SYSTEM (28-00-00)
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COPYRIGHT

2007 BY DART AEROSPACE LTD.
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THIS DOCUMENT IS PRIVATE AND CONFIDENTIAL AND IS SUPPLIED ON THE EXPRESS CONDITION THAT IT IS NOT TO BE USED FOR ANY PURPOSE OR COPIED OR COMMUNICATED TO ANY
OTHER PERSON WITHOUT WRITTEN PERMISSION FROM DART AEROSPACE LTD.
Revision: 6
Date: 13.08.26
28.1 GENERAL
This chapter provides instructions for maintenance
of the airframe-mounted fuel supply system. Refer
to Chapter 76 for engine fuel system and control
linkage.
Fuel flows from the boost pumps (12, Figure 28-1)
to a manifold valve (2). The manifold valve has
internal check valves which prevent back flow in
the event that one boost pump should fail. The
manifold has thermal relief provisions, which
consist of very small orifices, to allow a small
amount of fuel to return to the fuel cells to prevent
thermal pressure buildup when the helicopter is
not operating.
Fuel flows from the manifold valve (2) to the fuel
shutoff valve (4). The shutoff valve is electrically
operated and is controlled by the pilot. It
incorporates a red-painted, manual override
handle to serve as a visual indication of the shutoff
valve position. It also permits manual operation
during maintenance procedures, when electrical
power is not available.
A thermal relief valve is an integral part of the
main shutoff valve. The thermal relief valve
serves to relieve possible pressure buildup in the
upper portion of the fuel system when the main
fuel shutoff valve is off. The thermal relief valve
will open between 90 and 120 PSI.
Fuel flows from the fuel shutoff valve (4) to the
main fuel filter (5) in the engine compartment. The
filter incorporates an impending bypass warning
switch. In the event the pressure drop across the
filter indicates that the filter is becoming clogged,
the worded segment FUEL FILTER on the caution
panel will light up to indicate the impending bypass
condition. If the filter is clogged to the extent that
insufficient fuel will pass, a bypass valve will open
and permit fuel to bypass the filter. A pressure
transmitter (1) is mounted adjacent to the filter. The
pressure transmitter causes the fuel pressure gage
on the instrument panel to indicate the boost pump
pressure.
Fuel flows from the main fuel filter (5) to the
helicopter engine. A warning system to indicate
failure of either fuel pump, on engine fuel control, is
provided. If either fuel pump should fail, the
pressure switch associated with that pump will cause
the worded segment ENG FUEL PUMP on the
caution panel to light.
28.2 SAFETY PRECAUTIONS
WARNING
ONLY APPROVED, EXPLOSION PROOF TYPE
LIGHTS ARE TO BE USED NEAR OPEN FUEL
CELLS AND FUEL LINES.
CAUTION
HANDLE CELL WITH EXTREME CARE DURING
REMOVAL AND INSTALLATION TO PREVENT
DAMAGE TO CELLS. DO NOT ATTEMPT TO
REMOVE, FOLD, OR INSTALL A CELL WHEN
CELL TEMPERATURE IS BELOW 65°F (18°C).
ALL FUELING AND DEFUELING OPERATIONS
SHALL BE CONDUCTED IN AREAS WHERE FIRE
HAZARDS ARE REDUCED TO A MINIMUM. FOR
COMPLETE DEFUELING / REFUELING
PROCEDURES READ AND FOLLOW
INSTRUCTIONS CONTAINED IN CHAPTER 12 OF
THIS MANUAL.