TM 1-1510-224-10 (4) Flight   instrument   lights.      Each   individual flight  instrument  contains  internal  lamps  for  illumination. The circuit is protected by the 7.5-ampere circuit breaker placarded  FLT   INST,   located   on   the   overhead   circuit breaker panel (fig.  2-9).  Control is provided by the two rheostat switches placarded  PILOT INSTRUMENTS  and COPILOT   INSTRUMENTS,   located   on   the   overhead control  panel  (fig.    2-15).    Turning  the  control  clockwise from   OFF,   illuminates   the   lights   and   increases   their brilliance. (5) Engine  instrument  lights.    Each  individual engine instrument contains internal lamps for illumination.    The  circuit  is  protected  by  the  7.5-ampere circuit   breaker   placarded   FLT   INST   on   the   overhead circuit  breaker  panel  (fig.    2-9).    Control  is  provided  by the rheostat switch placarded   ENGINE  INSTRUMENTS on  the  overhead  control  panel  (fig.    2-15).    Turning  the control  clockwise  from   OFF,  illuminates  the  lights  and increases their brilliance. (6) Overhead panel lights.  Lamps illuminating the overhead circuit breaker, control, and fuel management   panels   are   protected   by   the   7.5-ampere circuit breaker, placarded  OVHD on the overhead circuit breaker   panel   (fig.      2-9).      Control   is   provided   by   the rheostat switch placarded  OVERHEAD  PANEL,  located on  the  overhead  control  panel  (fig.    2-15).    Turning  the control  clockwise  from   OFF,  illuminates  the  lights  and increases their brilliance. (7) Subpanel  and  console  lights.      Lights   on the  pilot's  and  copilot's  subpanels,  console  edge-lighted panels,  mission  control  panel,  and  pedestal  extension panels  are  protected  by  the  7  5-ampere  circuit  breaker, placarded   SUBPNL    &    CONSOLE    on    the    overhead circuit  breaker  panel  (fig.    2-9).    Control  is  provided  by two    rheostat    switches    placarded     SUBPANEL     and CONSOLE  on  the  overhead  control  panel  (fig.    2-15). Turning the controls clockwise from  OFF, illuminates the lights and increases their brilliance. (8) Free air temperature light.  Two post lights are   mounted   adjacent   to   the   outside   air   temperature gage on the left cockpit sidewall.  The circuit is protected by  the  7.5-ampere  circuit  breaker  placarded   FLT  INST on the overhead circuit breaker panel (fig.  2-9).  Control is provided by a pushbutton switch adjacent to the gage. Light intensity is not adjustable. b. Cabin Lighting. (1) Threshold    and    spar    cover    lights.        A threshold  light  is  installed  just  above  floor  level  on  the left  side  of  the  cabin,  just  inside  the  cabin  door.    A  spar cover light   is   installed   on   the   left   side   of   the   sunken   aisle, immediately aft of the main spar cover.  Both circuits are protected  by  a  5-ampere  circuit  breaker  located  in  the battery box, and are connected to the emergency battery bus.      Both   lights   are   controlled   by   a   switch   mounted adjacent    to    the    threshold    light.        If    the    lights    are illuminated,   closing   the   cabin   door   will   automatically extinguish them. (2) Cabin aisle lights.  Three cabin aisle lights are  installed  in  the  cabin  aisle.    Control  is  provided  by the  CABIN  LIGHTS  BRIGHT  -  DIM  switch  located  on the pilot's subpanel. (3) Cabin utility lights.  A utility light is located adjacent  to  each  overhead  flood  light  in  the  cabin  area. The    utility    lights    are    individually    controlled    by    the rheostatswitch placarded  OFF  -  ON  -  BRT,  located  on the  back  of  each  light.    A  momentary    ON   switch   is located in the center of the rheostat.  The light is capable of   producing   a   red   or   white   spotlight   by   adjusting   a diaphragm,  located  in  front  of  the  light.    To  remove  the light  from  the  stationary  position,  pull  down  on  the  light. The light is connected to the light housing by an 11 inch coiled   cord   that   extends   to   approximately   50   inches. Power   for   the   utility   lights   is   provided   through   the   5- ampere  circuit  breaker  placarded   CABIN   LIGHTS,   on the overhead circuit breaker panel. (4) Cabin  door  latching  mechanism  light.     A light    is    provided    to    check    the    cabin    door    latching mechanism.    It  is  controlled  by  a  red  pushbutton  switch located adjacent to the round observation window, which is just above the second step. 2-77. EMERGENCY LIGHTING SYSTEM. An independent battery-operated emergency lighting system is installed. The system is actuated automatically  by  shock,  such  as  a  forced  landing.    It provides    adequate    lighting    inside    and    outside    the fuselage   to   permit   the   occupants   to   read   instruction placards   and   locate   exits.      An   inertia   switch,   when subjected  to  a  2  G  (minimum)  shock  will  illuminate  the interior lights in the cockpit, forward and aft cabin areas, exterior  lights  aft  of  the  emergency  exit,  and  aft  of  the cabin  door.    The  battery  power  source  is  automatically recharged by the aircraft electrical system. a. Emergency    Lighting    System    Operation.        An emergency    lights    override    switch,    located    on    the overhead control panel (fig.  2-15), is provided to turn the system  off  if  it  is  accidentally  actuated.    The  switch  is placarded  EMERGENCY  OFF/RESET  -  AUTO  -  TEST. Should  the  system  accidentally  actuate,  the  emergency lights    will    illuminate.        Placing    the    switch    in    the momentary   OFF/RESET    position    will    extinguish    the lights.      To   test   the   system,   place   the   switch   in   the momentary  TEST  position.  The  lights  should  illuminate. Moving  the  switch  to  the   OFF/RESET  position  will  turn the system off and reset it.  The switch is normally in the AUTO position. 2-86