2-19. FOREIGN OBJECT DAMAGE CONTROL.
The engine has an integral air inlet screen
designed to obstruct objects large enough to damage the
2-20. ENGINE ICE PROTECTION SYSTEMS.
After the ice vanes have been
manually extended, they may be
mechanically actuated only. No
electrical extension or retraction
shall be attempted as damage to
the actuator may result. Linkage in
the nacelle area must be reset prior
to operation of the electric system.
An inertial separation system is built into each
engine air inlet to prevent moisture particles from entering
the engine inlet plenum under icing conditions. A
movable vane and a bypass door are lowered into the
airstream when operating in visible moisture at 5'C or
colder, by energizing electrical actuators with the
switches, placarded ICE VANE RETRACT EXTEND,
located on the overhead control panel. A mechanical
backup system is provided, and is actuated by pulling the
T-handles just below the pilot's subpanel placarded ICE
VANE #1 ENG #2 ENG. Decrease airspeed to 160 knots
or less to reduce forces for manual extension. Normal
airspeed may then be resumed.
The vane deflects the ram airstream slightly
downward to introduce a sudden turn in the airstream to
the engine, causing the moisture particles to continue on
undeflected, because of their greater momentum, and to
be discharged overboard.
While in the icing flight mode, the extended
position of the vane and bypass door is indicated by green
annunciator lights, #1 VANE EXT and #2 VANE EXT.
In the non-ice protection mode, the vane
and bypass door are retracted out of the airstream by
placing the ice vane switches in the RETRACT position.
The green annunciator lights will extinguish. Retraction
should be accomplished at 15°C and above to assure
adequate oil cooling. The vanes should be either
extended or retracted; there are no intermediate positions.
If for any reason the vane does not attain
the selected position within approximately 15 seconds, a
yellow #1 VANE FAIL or #2 VANE FAIL light illuminates
on the caution/advisory panel. In this event, the manual
backup system should be used. When the vane is
successfully positioned with the manual system, the
yellow annunciator lights will extinguish.
Engine Air Inlet Deice System.
Description. Hot engine exhaust gas is
utilized for heating the air inlet lips to prevent the
formation of ice. Hot exhaust gas is picked up inside
each engine exhaust stack and carried by plumbing to the
inlet lip. The gas flows through the inside of the lip to the
bottom where it is allowed to escape.
Engine air inlet deice system switches.
(Provisions only system not installed. ) Two switches
placarded ENG INLET LIP HEAT #1, #2 OFF/ ON,
located on the overhead control panel, operate solenoid
valves in the exhaust system of each engine. These
valves control the flow of hot exhaust gases to the inlet air
Fuel heater. A oil-to-fuel heat exchanger,
continuously and automatically to heat the fuel sufficiently
to prevent ice from collecting in the fuel control unit.
Each pneumatic fuel control line is protected against ice.
Power is supplied to each fuel control air line jacket
heater by two switches actuated by moving the condition
levers in the pedestal out of the fuel cutoff range. Fuel
control heat is automatically turned on for all engine
2-21. ENGINE FUEL CONTROL SYSTEM.
Description. The basic engine fuel system
consists of an engine driven fuel pump, a fuel control unit,
a fuel flow divider, a dual fuel manifold and fourteen fuel
Fuel Control Unit. One fuel control unit is
mounted on the accessory case of each engine. This unit
is a hydro-mechanical metering device which determines
the proper fuel schedule for the engine to produce the
amount of power requested by the relative position of its
power lever. The control of developed engine power is
accomplished by adjusting the engine compressor turbine
(N1) speed. N speed controlled by varying the amount of
fuel injected into the combustion chamber through the
fuel nozzles. Engine shutdown is accomplished by
moving the appropriate condition lever to the full aft,
FUEL CUT-OFF position, which shuts off the fuel supply.