TM 1-1510-218-10 2-37 T    The  basic  engine  fuel  system  consists  of  an engine driven fuel pump, a fuel control unit, a dual fuel manifold,  14  fuel  nozzles,  and  a  fuel  purge  system.   The  fuel  purge  system  forces  residual  fuel  from  the manifolds   to   the   combustion   chamber,   where   it   is consumed. a.   One fuel control unit is 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.   N₁  speed  is  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   CUTOFF  position,  which shuts off the fuel supply. 2-27.  POWER LEVERS. CAUTION Moving the power levers into reverse range without  the  engines  running  may  result  in damage to the reverse linkage mechanisms.  Two   power   levers   are   located   on   the   control pedestal, Figures 2-7  and  2-9.   These levers regulate power  in  the  reverse,  idle,  and  forward  range,  and operate  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.   Distinct   movement   (pulling   up   and   then   aft   on   the power lever) by the pilot is required for reverse thrust.   Placard  beside  the  lever  travel  slots reads  POWER.   Upper lever travel range is designated INCR (increase), supplemented by an arrow pointing forward.    Lower  travel  range  is  marked   IDLE /  LIFT and  REVERSE.  A placard below the lever slots reads, CAUTION    –    REVERSE    ONLY    WITH    ENGINES RUNNING. 2-28.  CONDITION LEVERS. Two  condition  levers  are  located  on  the  control pedestal.    Each  lever  starts  or  stops  the  fuel  supply, and controls the idle speed for its engine.   The levers have  three  placarded  positions:   FUEL  CUTOFF,  LO IDLE,    and   HIGH   IDLE.        In   the   FUEL    CUTOFF position, the condition lever controls the cutoff function of its engine-mounted fuel control unit.  From LO IDLE to  HIGH  IDLE,  they  control  the  governors  of  the  fuel control units to establish minimum fuel flow levels.  LO IDLE  position  sets  the  fuel  flow  rate  to  attain  52%  ± 2%  C  D ; 56-58%  T  ,  (at  sea  level)  minimum  N₁ and HIGH   IDLE    position   sets   the   rate   to   attain   70% minimum  N₁.    The  power  lever  for  the  corresponding engine can select N₁ from the respective idle setting to maximum  power.    An  increase  in  low  idle  N₁  will  be experienced at high field elevation. 2-29.  FRICTION LOCK KNOBS. Four    friction    lock    knobs    are    located    on    the control   pedestal   to   adjust   friction   drag.      Refer   to Figures 2-7 and 2-9.  One knob is below the propeller levers, one  below the condition levers, and two under the power levers.  When a knob is rotated clockwise, friction  restraint  is  increased  opposing  movement  of the affected lever as set by the pilot.   Counterclockwise   rotation   of   a   knob   will   decrease friction   drag   thus    permitting    free    and    easy    lever movement.        Two    FRICTION   LOCK   placards   are located on the pedestal adjacent to the knobs. 2-30.  ENGINE FIRE DETECTION SYSTEM C  D  T1 . A flame surveillance system is installed on each engine to detect external engine fire and provide alarm to the pilot.  Both nacelles are monitored, each having a   control   amplifier   and   three   detectors.      Electrical wiring connects all sensors and control amplifiers to dc power and to the cockpit visual alarm units.  In each nacelle,  one  detector  monitors  the  forward  nacelle,  a second monitors the upper accessory area, and a third the lower accessory area. a.   Fire  emits  an  infrared  radiation  that  will  be sensed  by  the  detector,  which  monitors  the  area  of origin.  Radiation exposure activates the relay circuit of a  control  amplifier,  which  causes  signal  power  to  be sent    to    cockpit    warning    systems.        An    activated surveillance   system   will   return   to   the   standby   state after  the  fire  is  out.    The  system  includes  a  functional test switch. b.  Warning Of Internal Nacelle Fire. (1)   The red  MASTER WARNING light on the glare shield illuminates accompanied by the illumination of a red warning light in the appropriate fire control T-handle, placarded  FIRE PULL.  Fire detector circuits   are   protected   by   a   single  5 -ampere   circuit breaker,     placarded     FIRE    DETR    located    on    the overhead circuit breaker panel, Figure 2-16.