TM 1-1510-225-10 2-87 (1)   Use Of Pilot  and Copilot Oxygen Masks.   To don the mask, grasp the red levers protruding from the  stowage  compartment  and  pull  the  mask  down.   Inflate the mask harness by pressing the red lever on the  left  side  of  the  regulator  and  then  don  the  mask and  release  the  lever.    Three  modes  of  operation  are available   which   are   controlled   by   a   selector   lever located on the bottom right side of the regulator: (a)  NORMAL  Mode.    When  the  selector lever  is  placed  in  the    NORMAL  position,  oxygen  is automatically  mixed  with  the  proper  amount  of  air  at the  aircraft's  altitude.    The    NORMAL  mode  may  be selected at the discretion of the user at any altitude. (b)  100% Mode.  When the selector lever is placed in the   100%  position,  pure  undiluted  oxygen is  supplied  to  the  mask.    The    100%  mode  may  be selected at the discretion of the user at any altitude. (c)  Emergency (EMERG) Mode.  Turning the   EMERG   knob,   located   on   the   bottom   of   the regulator, places the mask in the emergency mode.  In the   EMERG,   mode   the   regulator   will   supply   100% undiluted oxygen to the user under a positive pressure to  the  facemask.    The  emergency  mode  should  be used if smoke or fumes are present in the aircraft.  The emergency mode may be selected at the discretion of the user at any altitude. e.   Passenger Oxygen System. The passenger oxygen system is of the constant flow type.   Anytime the cabin pressure altitude exceeds approximately    12,500    feet,    a    barometric    pressure switch automatically energizes a solenoid which opens the passenger oxygen system shut-off valve.  The pilot or  copilot  can  open  the  valve  manually  anytime  by pulling    out    the    passenger    oxygen,    manual-control handle, located on the right side of the pedestal.  Once the passenger oxygen system shut -off valve has been opened,  either  automatically  or  manually,  oxygen  will flow   into   the   passenger   oxygen   supply   line   if   the primary  oxygen  system  line  has  been  charged.    That is, if the oxygen supply cylinder contains oxygen and the  PULL  ON  SYS  READY  handle  in  the  cockpit  is pulled out.  When the passenger oxygen supply line is charged, the green  PASS OXY ON annunciator on the caution/advisory annunciator panel will illuminate.  The cabin    lights,    foyer    light,    and    the    center    baggage compartment  light  will  be  illuminated  in  the  full  bright mode   regardless   of   the   position   of   the   cabin  lights switch,   placarded    CABIN    BRIGHT   /    DIM   /    OFF, located on the copilot's subpanel.  Oxygen pressure in the   passenger   line   causes   the   passenger   oxygen masks to drop out of the overhead mask compartments.  The lanyard on the mask must then be pulled out in order to start the flow of oxygen. NOTE The   lanyard   valve   pin   must   be   manually reinserted into the valve to stop the flow of oxygen    when    the    mask    is    no    longer needed. The  passenger  oxygen  can  be  shut  off  and  the remaining   oxygen   isolated   to   the   crew   and  first  air outlets   by   pulling   the   OXYGEN   CONTROL  circuit breaker,  located  on  the  right  sidewall  circuit  breaker panel, providing the  PASSENGER  MANUAL  O  RIDE handle is pushed in to the OFF position. f.    First  Aid  Oxygen  Mask.    A  first  aid  oxygen mask    is    installed    in    the    aft    cabin    area    as    a supplemental or emergency source of oxygen.   Anytime  the  primary  oxygen  supply  line  is  charged, oxygen can be obtained from the first aid oxygen mask located   in   the   toilet   area,   by   manually   opening   the overhead access door, placarded FIRST AID OXYGEN  – PULL,  and  opening  the ON  –  OFF valve inside the box.  A placard which reads, NOTE:  CREW SYS  MUST  BE  ON,  reminds  the  user  that  the   PULL ON SYS READY handle in the cockpit must be pulled out  before  oxygen  will  flow  from  the  first   aid  oxygen mask. 2-62.  WINDSHIELD WIPERS. a.   Description.          Two     electrically     operated windshield   wipers   are   provided   for   use   at   all   flight speeds.      A   rotary   switch,   placarded   WINDSHIELD WIPERS,    located    on    the    overhead    control    panel, selects   mode   of   windshield   wiper   operation.      An information placard above the switch states,  DO  NOT OPERATE  ON  DRY  GLASS.    Function  positions  of the  switch,  as  read  clockwise,  are  placarded: PARK  /    OFF  /  SLOW / FAST.  When the switch is held in the spring-loaded  PARK  setting,  the  blades   will  return  to their  normal  inoperative  position  on  the  glass,  then, when   released,   the   switch   will   return   to   the    OFF position,  terminating  windshield  wiper  operation.    The FAST    and    SLOW    switch    positions    are    separate operating   speed   settings   for   wiper   operation.      The windshield wiper circuit is protected by one 10-ampere circuit breaker, placarded  WSHLD WIPER, located on the right sidewall circuit breaker panel. CAUTION Do  not  operate  windshield  wipers  on  dry glass.  Such action can damage the linkage as well as scratch the windshield glass.  b.  Normal Operation. To start, turn WINDSHIELD   WIPER   switch   to   FAST    or   SLOW speed,  as  desired.    To  stop,  turn  the  switch  to  the PARK  position  and  release.   The  blades  will  return  to