TM 1-1510-223-10 Change 3          2-27 In this event, the appropriate # 1 or # 2 ICE VANE POW- ER SELECT switch should be placed in the STBY posi- tion. Once the vane is successfully positioned, using the standby (STBY) system, the amber annunciator(s) will extinguish and the applicable green #1 VANE EXT or #2 VANE EXT annunciator(s) will illuminate. c.   Engine Anti-Ice System. (1)    Air Inlet.  A small duct, facing into the exhaust flow  in  the  engine’s  left  exhaust  stack  diverts  a  small portion of the engine exhaust gases to the engine air inlet lip. The gases are circulated through the engine air inlet lip and then exhausted through a duct in the engine’s right exhaust stack. The continuous flow of hot engine exhaust gases heats the engine air inlet lip, preventing the formation of ice. Two switches placarded ENG INLET LIP HEAT #1 and #2 (located on the overhead control panel, fig. 2-13), operate solenoid valves in the lip heat exhaust plumbing. These valves control the flow of hot exhaust gasses to the inlet air lip assemblies. (2)    Fuel  Heater.    An  oil-to-fuel  heat  exchanger, located in the engine accessory case, operates continu- ously  and  automatically  to  heat  the  fuel  sufficiently  to prevent ice from collecting in the fuel control unit. 2-21.   ENGINE FUEL CONTROL SYSTEM. a.   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, fourteen fuel nozzles and a purge system. The fuel purge system forces resid- ual fuel from the manifolds to the combustion chamber where it is consumed. b.   Fuel Control Unit. One fuel control unit is mounted on the accessory case of the engine. This unit is a hydro- pneumatic metering device which determines the proper fuel flow 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 accom- plished  by  adjusting  the  engine  gas  generator  (N₁) speed. N₁ speed is controlled by varying the amount of fuel injected into the combustion chamber through the fuel nozzles. Engine shutdown is accomplished by mov- ing the appropriate CONDITION lever to the full aft FUEL CUTOFF position, which shuts off the fuel supply. 2-22.   POWER LEVERS. CAUTION Moving the POWER levers below the flight idle gate without the engines running may result in damage to the reverse mechanism linkage. The two POWER levers are located on the control pedestal (fig. 2-12), and are placarded POWER. These levers regulate power in the reverse, idle and forward ranges, operating so that forward movement increases engine power. Power control is accomplished through adjustment of the N₁ speed governor in the fuel control unit. Power is increased when N₁ RPM is increased. The POWER levers also control propeller reverse pitch. Dis- tinct movement (pulling up and then aft on the POWER lever) by the pilot is required for operation in the ground fine and reverse ranges. Forward lever travel range is designated INCR (increase), supplemented by an arrow pointing  forward.  Lever  travel  range  is  marked  IDLE, LIFT, GROUND FINE, LIFT, and REVERSE. A placard below  the  lever  slots  reads:  CAUTION  -  REVERSE ONLY WITH ENGINES RUNNING. 2-23.   CONDITION LEVERS. The two CONDITION levers are located on the control pedestal (fig. 2-12). Each lever starts and stops the fuel supply, and controls the idle speed for its respective en- gine. The levers have three placarded positions: FUEL CUTOFF, LOW IDLE, and HIGH IDLE. In the FUEL CUT- OFF position, the CONDITION lever controls the cutoff function  of  its  engine-mounted  fuel  control  unit.  From LOW IDLE to HIGH IDLE, they control the governors of the fuel control units to establish minimum fuel flow lev- els. LOW IDLE position sets the fuel flow rate to attain 62% minimum N₁ and HIGH IDLE position sets the rate to attain 71 to 73% minimum N₁. The POWER lever for the corresponding engine can select N₁ from the respec- tive idle setting, up to maximum power. An increase in low idle N₁ will be experienced at high field elevation. 2-24.   FRICTION LOCK KNOBS. Four friction lock knobs placarded FRICTION LOCK are located on the control pedestal (fig. 2-12), to adjust friction drag. One knob is below the propeller levers, one below the CONDITION levers, and two below the POW- ER levers. When the knobs are rotated clockwise, friction is increased, opposing movement of the affected lever as set by the pilot. Counterclockwise rotation of the knobs will decrease friction, thus permitting free and easy lever movement. 2-25.   ENGINE FIRE DETECTION SYSTEM. a.   Description. A fire detection system (fig. 2-14), is installed to provide an immediate warning in the event of a fire or overtemperature in the engine compartment. The mainelementofthesystemisatemperaturesensingtube, routed continuously throughout the engine compartment terminating in a responder unit. The responder unit is mounted in the accessory area on the upper left hand enginemounttruss,justforwardoftheenginefirewall.The