TM 55-1510-219-10 a. Turbine  Gas  Temperature  Indicators.    Two  TGT gages on the instrument panel (fig.  2-28) are calibrated in degrees Celsius. 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    power turbine for the corresponding engine. b. Engine Torquemeters.    Two  torquemeters  on  the instrument panel (fig.  2-28) indicate torque applied to the propeller  shafts  of  the  respective  engines.    Each  gage shows   torque   in   percent   of   maximum   using   2   percent graduations and is actuated by an electrical signal from a pressure    sensing    system    located    in    the    respective propeller     reduction     gear     case.          Torquemeters     are protected   by   individual   0.      5ampere   circuit   breakers placarded  TORQUEMETER  #1  or  #2  on  the  overhead circuit breaker panel (fig.  2-26). c. Turbine  Tachometers.    Two  tachometers  on  the instrument  panel  (fig.    2-28)  register  compressor  turbine RPM  (N1)  for  the  respective  engine.    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.      Two gages  on  the  instrument  panel  (fig.    2-28)  panel  register oil pressure in PSI and oil temperature in °C.  Oil pressure is  taken  from  the  delivery  side  of  the  main  oil  pressure pump.  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    transmitters    installed    on    the respective   engine.      Both   instruments   are   protected   by 5ampere circuit breakers, placarded OIL PRESS and OIL TEMP  #1  or  #2,  on  the  overhead  circuit  breaker  panel (fig.  2-26). e. Fuel    Flow    Indicators.        Two    gages    on    the instrument  panel  (fig.    2-28)  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   1/2 ampere circuit breakers placarded FUEL FLOW #1 or #2, on the overhead circuit breaker panel (fig.  2-26). Section IV.  FUEL SYSTEM 2-34.  FUEL SUPPLY SYSTEM. The engine fuel supply system (fig.  2-12) consists of     two     identical     systems     sharing     a     common     fuel management  panel  and  fuel  crossfeed  plumbing.    Each fuel system consists of five interconnected wing tanks, a nacelle   tank,   an   auxiliary   inboard   fuel   tank.      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 oilto-fuel heat exchanger unit), a   tank   vent   system,   a   tank   vent   heating   system   and interconnecting wiring and plumbing.  Refer to Section IV for  fuel  grades  and  specifications.    Fuel  tank  capacity  is shown in Table 2-2. a. Engine Driven Boost Pumps. CAUTION 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 #1 or #2 FUEL PRESS lights and the simultaneous illumination of both MASTER WARNING  lights.    Refer  to  Chapter 9.  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   primary   high-pressure   pump   for   engine starting  and  all  normal  operations.    Either  the  engine- driven    boost    pump    or    standby    pump    is    capable    of supplying  sufficient  pressure  to  the  enginedriven  primary high-pressure   pump   and   thus   maintain   normal   engine operation. b. Standby Fuel Pumps.  A submerged, electrically- operated  standby  fuel  pump,  located  within  each  nacelle tank, serves as a backup unit for the engine-driven boost pump.      The   standby   pumps   are   switched   off   during normal  system  operations.    A  standby  fuel  pump  will  be operated during crossfeed to pump fuel from one system to the opposite engine.  The correct pump is automatically selected   when   the   CROSSFEED   switch   is   activated. Each standby fuel pump has an inertia switch included in the  power  supply  circuit.    When  subjected  to  a  5  to  6  G shock  loading,  as  in  a  crash  situation,  the  inertia  switch will remove electrical power from the standby fuel pumps. The standby fuel pumps are protected 2-28