2-24. FOREIGN OBJECT DAMAGE CONTROL.
The engine has an integral air inlet screen
designed to obstruct objects large enough to damage
The engine anti-ice system (ice vanes)
should be on (extended) for all ground
operations to minimize ingestion of ground
debris. It may be necessary to turn off
engine anti-ice (retract ice vanes) in warm
ambient conditions to preclude exceeding
engine gas temperature limits.
2-25. ENGINE ICE PROTECTION SYSTEMS.
actuated only. No electrical extension or
retraction shall be attempted as damage to
the electric actuator will result. Linkage in
the nacelle area must be reset prior to
operation of the electric system.
a. Inertial Separator. 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
by-pass door are lowered into the air stream when
operating in visible moisture at +5°C or colder, by
energizing electrical actuators with the switches,
placarded ICE VANE RETRACT/EXTEND C D T1
and ICE VANE CONTROL/ON T2 , located on the
overhead control panel. Refer to Figure 2 -15. 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 and ICE
VANE #2 ENG C D1 T2 and ICE VALVE # 1 ENG and
ICE VALVE # 1 ENG T1 . Decrease airspeed to
160 knots or less to reduce forces for manual
extension. Normal airspeed may then be resumed.
(1) The vane deflects the ram air stream
slightly downward to introduce a sudden turn in the air
stream to the engine, causing the moisture particles to
continue on undetected, because of their greater
momentum, and to be discharged overboard.
(2) While in the icing flight mode, the
extended position of the vane and by-pass door is
indicated by green annunciator lights, #1 VANE EXT
and #2 VANE EXT.
(3) In the non-ice protection mode, the vane
and by-pass door are retracted out of the air stream 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
(4) If for any reason the vane does not attain
the selected position within 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. During
manual system use, the electric motor switch position
must match the manual handle position for a correct
b. Engine Air Inlet Deice C D . Engine exhaust
heat is utilized for heating the engine air inlet lips. Hot
exhaust is picked up by a scoop inside each engine
exhaust stack and plumbed downward to connect into
each end of the inlet lip. Exhaust flows through the
inside of the lip downward to the bottom where it is
plumbed out through the bottom of the nacelle. No
shut-off or temperature indicator is necessary for this
c. Engine Air Inlet Deice T . A small duct,
facing into the exhaust flow of the engine's left exhaust
stack, diverts a small portion of the engine exhaust
gases to the engine air inlet anti-ice lip. The gases are
circulated through the engine air inlet anti-ice lip and
then exhausted through a duct to the engine's right
exhaust stack. The continuous flow of hot engine
exhaust gases heats the engine air inlet anti-ice lip,
preventing the formation of ice.
d. Fuel Heater. An oil-to-fuel heat exchanger,
located on the engine accessory case, operates
continuously and automatically to heat the fuel
sufficiently to prevent ice from collecting in the fuel
control unit. Each pneumatic fuel control line is
automatically turned on for all engine operations.
2-26. ENGINE FUEL CONTROL SYSTEM.
C D 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 14 fuel nozzles. The
fuel flow divider acts as a drain valve to clear residual
fuel after engine shutdown.