TM 1-1510-223-10 2-30. ENGINE STARTER-GENERATORS. One  starter-generator  is  mounted  on  the  accessory drive section of each engine.  Each starter-generator is able to function either as a starter or as a generator.  In the  starter  function,  28  volts  DC  is  required  to  power rotation.  In the generator function, each unit is capable of 400 amperes DC output When the starting function is selected,    the    starter    control    circuit    receives    power through the respective 5-ampere START CONTR circuit breaker on the overhead circuit breaker panel (fig.  2-7), from   either   the   aircraft   battery   or   an   external   power source.    When  the  generating  function  is  selected,  the starter-generator provides electrical power. 2-31. ENGINE INSTRUMENTS. The engine instruments are arranged vertically near the center of the instrument panel (fig.  2-16). a. Turbine  Gas  Temperature  Indicators.    The  two TGT  gages  on  the  instrument  panel  are  calibrated  in degrees Celsius (fig.  2-16).  Each gage is connected to thermocouple  probes  located  in  the  hot  gases  between the turbine wheels.  The gages register the temperature present  between  the  compressor  turbine  and  a  power turbine for the corresponding engine. b. Engine  Torquemeters.    The   two   torquemeters on  the  instrument  panel  indicate  torque  applied  to  the propeller  shafts  of  the  respective  engines  (fig.    2-16). Each  gage  shows  torque  in  percent  of  maximum  using two percent graduations and is actuated by an electrical signal    from    a    torque    transmitter    mounted    on    the reduction gearbox which senses engine internal torquemeter  pressure.    The  torquemeters  are  protected by    individual    0.5-ampere    circuit    breakers    placarded TORQUE  METER  #  1  or  #2  on  the  overhead  circuit breaker panel (fig.  2-7). c. Turbine Tachometers.   The two tachometers on the  instrument  panel  register  compressor  turbine  RPM (Ni)   for   the   respective   engine   (fig.      2-16).      These indicators   register   turbine   RPM   as   a   percentage   of maximum   gas   generator   RPM.      Each   instrument   is slaved    to    a    tachometer    generator    attached    to    the respective engine. d. Oil  Pressure/Oil  Temperature  Indicators.     The two gages on the instrument panel register oil pressure in   PSI   and   oil   temperature   in   °C   (fig.      2-16).      Oil pressure is taken from the delivery side of the main oil pressure pump. Warning annunciators placarded No.  1 OIL  PRESS  and  No.    2  OIL  PRESS  are  located  in  the warning annunciator panel. Oil temperature is transmitted  by  a  thermal  sensor  unit  which  senses  the temperature  of  the  oil  as  it  leaves  the  delivery  side  of the   oil   pressure   pump.      Each   gage   is   connected   to pressure  and  temperature  transmitters  installed  on  the respective engine.  Both instruments are protected by 5- ampere circuit breakers, placarded OIL PRESS and OIL TEMP # 1 or # 2, on the overhead circuit breaker panel (fig.  2-7). e. Fuel    Flow    Indicators.        Two    gages    on    the instrument panel (fig.  2-16) register the rate of flow for consumed  fuel  as  measured  by  sensing  units  coupled into the fuel supply lines of the respective engines.  The fuel   flow   indicators   are   calibrated   in   increments   of hundreds    of    pounds    per    hour.        Both    circuits    are protected by 5-ampere circuit breakers placarded FUFL FLOW  #1  or  #2,  on  the  overhead  circuit  breaker  panel (fig.  2-7). Section IV.  FUEL SYSTEM 2-32. FUEL SUPPLY SYSTEM. The engine fuel supply system (fig.  2-17) consists of two identical systems sharing a common fuel management   panel   (fig.      2-18)   and   fuel   crossfeed plumbing (fig.  2-19). Each main fuel system consists of five interconnected wing tanks, and a nacelle tank Each auxiliary    fuel    system    consists    of    one    tank    located between  the  nacelle  and  the  fuselage.    A  fuel  transfer pump is located within each auxiliary tank.  Additionally, the system has an engine-driven boost pump, a standby fuel pump located within each nacelle tank, a fuel heater (engine   oil-to-fuel   heat   exchanger   unit),   a   tank   vent system, a tank vent heating system, and interconnecting wiring and plumbing.  Total fuel tank capacity is shown in table 2-2.  Gravity feed fuel flow is shown in figure 2- 20. a. Engine Driven Boost Pumps. Engine  operation  using  only  the  enginedriven  primary (high   pressure)   fuel   pump   without   standby   pump   or engine-driven boost pump fuel pressure is limited to 10 cumulative     hours.     This     condition     is     indicated     by illumination   of   either   the   #   1   or   #   2   FUEL   PRESS warning  annunciator  and  the  simultaneous  illumination of  both  MASTER  WARNING  annunciators.  All  time  in this category shall be entered on DA Form 2408-13 for the  attention  of  maintenance  personnel.  A  gear-driven boost   pump,   mounted   on   each   engine   supplies   fuel under pressure to the inlet of the engine-driven 2-34