PULL   lights   in   the   fire   control   T-handles.   Pulling the  fire  control  T-handle  will  electrically  arm  the extinguisher  system  and  close  the  fuel  firewall  shut- off  valve  for  that  particular  engine.  This  will  cause the  red  light  in  the  PUSH  TO  EXTINGUISH  switch and  the  respective  red  No.  1  FUEL  PRESS  or  No.  2 FUEL  PRESS  light  on  the  warning  annunciator panel  to  illuminate.  Pressing  the  lens  of  the  PUSH TO  EXTINGUISH  switch  (after  lifting  one  side  of its  spring-loaded  clear  plastic  guard)  will  fire  the squib,  expelling  all  the  agent  in  the  cylinder  at  one time.   The   respective   yellow   caution   light,   No.   1 EXTGH  DISCH  or  No.  2  EXTGH  DISCH  on  the caution/advisory   annunciator   panel   and   the   master fault  caution  lights  on  the  glareshield  will  illuminate and   remain   illuminated,   regardless   of   the   master switch  position,  until  the  squib  is  replaced. c.  Fire  Extinguisher  System  Test  Switch.  A rotary   test   switch,   placarded   FIRE   PROTECTION TEST,  is  located  on  the  copilot’s  subpanel.  The  test functions,  placarded  EXTGH  -  No.  1  -  No.  2,  are arranged  on  the  left  side  of  the  switch  and  provide a  test  of  the  pyrotechnic  cartridge  circuitry.  During preflight,   the   pilot   should   rotate   the   test   switch through   the   two   positions   and   verify   the   illumina- tion  of  the  green  SQUIB  OK  light  on  the  PUSH  TO EXTINGUISH  switch  and  the  corresponding  yellow No.  1  or  No.  2  EXTGH  DISCH  light  on  the  caution/ advisory   annunciator   panel. d.   Fire   Extinguishing   System   Supply   Cylinder Gages.  A gage, calibrated in PSI, is mounted on each supply  cylinder  for  determining  the  level  of  charge and  should  be  checked  during  preflight  (Table  2-1). 2-27. OIL SUPPLY SYSTEM. Maximum  allowable  oil  consumption  is one  quart  per  10  hours  of  engine  opera- tion. a.  The  engine  oil  tank  is  integral  with  the  air- inlet  casting  located  forward  of  the  accessory  gear- box.   Oil   for   propeller   operation,   lubrication   of   the reduction   gearbox   and   engine   bearings   is   supplied TM  55-1510-221-10 by   an   external   line   from   the   high   pressure   pump. Two  scavenge  lines  return  oil  to  the  tank  from  the propeller  reduction  gearbox.  A  non-congealing  exter- nal  oil  cooler  keeps  the  engine  oil  temperature within  the  operating  limits.  The  capacity  of  each engine  oil  tank  is  2.3  U.S.  gallons.  The  total  system capacity  for  each  engine,  which  includes  the  oil  tank, oil   cooler,   lines,   etc.,   is   3.5   U.S.   gallons.   The   oil level  is  indicated  by  a  dipstick  attached  to  the  oil filler   cap.   Oil   grade,   specification   and   servicing points,  are  described  in  Section  IX,  Servicing  the warning  annun. b. The  oil  system  of  each  engine  is  coupled  to a  heat  exchanger  unit  (radiator)  of  tin-and-tube design.  These  exchanger  units  are  the  only  airframe mounted  part  of  the  oil  system  and  are  attached  to the  nacelles  below  the  engine  air  intake.  Each  heat exchanger   incorporates   a   thermal   bypass   which assists  in  maintaining  oil  at  the  proper  temperature range  for  engine  operation. 2-28. ENGINE CHIP DETECTION SYSTEM. A  magnetic  chip  detector  is  installed  in  the  bot- tom  of  each  engine  nose  gearbox  to  warn  the  pilot  of oil   contamination   and   possible   engine   failure.   The sensor   is   an   electrically   insulated   gap   immersed   in the  oil,  functioning  as  a  normally-open  switch.  If  a large  metal  chip  or  a  mass  of  small  particles  bridge the   detector   gap,   a   circuit   is   completed,   sending   a signal  to  illuminate  a  red  annunciator  panel  indica- tor light placarded No. 1 CHIP DETR or No. 2 CHIP DETR   and   the   MASTER   WARNING   lights.   Chip detector  circuits  are  protected  by  two  5-ampere  cir- cuit   breakers,   placarded   No.   1   CHIP   DETR   and No.  2  CHIP  DETR  on  the  overhead  circuit  breaker panel (fig. 2-26). 2-29. ENGINE IGNITION SYSTEM. a.  Description.  The  basic  ignition  system  con- sists  of  a  solid  state  ignition  exciter  unit,  two  igniter plugs,   two   shielded   ignition   cables,   pilot   controlled IGNITION   AND   ENGINE   START   switches   and the  ENG  AUTO  IGN  switch.  Placing  an  IGNITION AND  ENGINE  START  switch  to  ON  (forward)  will cause  the  respective  igniter  plugs  to  spark,  igniting the   fuel/air   mixture   sprayed   into   the   combustion Table 2-1. Engine Fire Extinguisher Gage Pressure TEMP  °C -40 -29 -18 -06 04 16 27 38 48 190 220 250 290 340 390 455 525 605 PSI to to to to to to to to to 240 275 315 365 420 480 550 635 730 2-25