TM 1-1510-224-10 (fig.  2-14).  The amount of aileron tab deflection from a neutral  setting,  as  indicated  by  a  position  indicator,  is relative only and is not in degrees. d. Rudder  Trim  Tab  Control.    The  rudder  trim  tab control knob, placarded   RUDDER  TAB  LEFT,  RIGHT, located  on  the  control  pedestal,  controls  adjustment  of the rudder trim tab (fig.  2-14).  The amount of rudder tab deflection, in units from a neutral setting, is indicated by a position indicator. 2-39.  WING FLAPS. The slot-type wing flaps are electrically  operated  and consist  of  two  sections  for  each  wing.    These  sections extend   from   the   inboard   end   of   each   aileron   to   the junction  of  the  wing  and  fuselage.    During  extension  or retraction,  the  flaps  are  operated  as  a  single  unit,  with each section actuated by a separate jackscrew actuator. The   actuators   are   driven   through   flexible   shafts   by  a single   reversible   electric   motor.)Wing   flap   position   is indicated  in  percent  of  travel  by  a  flap  position  indicator on    the    center    subpanel.        Full    flap    extension    and retraction  time  is  approximately  11  seconds.    The  flap control  switch  is  located  on  the  control  pedestal.    No emergency wing flap actuation system is provided.  With flaps   extended   beyond   the    APPROACH   position,   the landing gear warning horn will sound, unless the landing gear  is  down  and  locked.    The  circuit  is  protected  by  a 20-ampere   circuit   breaker,   placarded   FLAP   MOTOR, located on the overhead circuit breaker panel (fig.  2-9). a. Wing   Flap   Control   Switch.      Flap   operation   is controlled by a three-position switch with a flap-shaped handle on the control pedestal (fig.  2-14).  The handle of this   switch   is   placarded   FLAP.      Switch   positions   are placarded:  FLAP - UP - APPROACH and  DOWN.  The amount  of  extension  of  the  flaps  is  established  by  the position    of    the    flap    switch    as    follows:        UP    -    0%, APPROACH  -  40%, and  DOWN 100%.    Limit  switches, mounted   on   the   right   inboard   flap,   establish   the   flap travel.    The  flap  control  switch,  limit  switch,  and  relay circuits   are   protected   by   a   5-ampere   circuit   breaker, placarded    FLAP   CONTR,    located    on    the    overhead circuit    breaker    panel    (fig.        2-9).        Intermediate    flap positions    between    UP    and    APPROACH    cannot    be selected.        For    intermediate    flap    positions    between APPROACH and  DOWN, the  APPROACH position acts as  an  off  position.    To  return  the  flaps  to  any  position between   full   DOWN   and   APPROACH   place   the   flap switch to UP  and  when  desired  flap  position  is  obtained, return the switch to   APPROACH  detent.    To  return  the flaps  to  full  UP,  place  the  flap  switch  to  the   UP  detent position.    To  return  the  flaps  to   APPROACH,  move  the flap    switch    to    the     UP    position    and    then    to    the APPROACH  detent  position.    In  the  event  that  any  two adjacent   flap   sections   extend   3   to   5   degrees   out   of phase with the other, a safety mechanism is provided to discontinue power to the flap motor. b. Wing  Flap  Position  Indicator.    Flap  position  in percent  of  travel  from  O  percent  (UP)  to  100  percent (DOWN)  is  shown  on  an  indicator,  placarded   FLAPS, located on the center subpanel (fig.  2-8).  The approach and   full   down   flap   positions   are   14   and   35   degrees, respectively.  The flap position indicator is protected by a 5-ampere    circuit    breaker,    placarded    FLAP    CONTR, located on the overhead circuit breaker panel (fig.  2-9). Section VI.  PROPELLERS 2-40.  DESCRIPTION. A four-blade aluminum propeller is installed on each engine.  The propeller is full feathering, constant speed, variable-pitch,   counterweighted,   and   reversible;   and   is controlled  by  engine  oil  pressure  through  single  action, engine   driven   propeller   governors.      The   propeller   is flange    mounted    to    the    engine    shaft.        Centrifugal counterweights,  assisted  by  a  feathering  spring,  move the blades toward the low RPM (high pitch) position and into the feathered position.  Governor boosted engine oil pressure   moves   the   propeller   to   the   high   RPM   (low pitch) hydraulic stop and reverse position.  The propeller has   no   low   RPM   (high   pitch)   stops;   this   allows   the blades   to   feather   after   engine   shutdown.      Low   pitch propeller  position  is  determined  by  the  low  pitch  stop, which    is    a    mechanically    actuated,    hydraulic    stop. Ground  fine  and  reverse  blade  angles  are  controlled  by the POWER levers in the ground fine and reverse range. Both manual and automatic propeller feathering systems 2-41.  FEATHERING PROVISIONS. are   provided.      Manual   feathering   is   accomplished   by pulling the corresponding  PROP  lever  aft,  past  a  friction detent.  To unfeather, the PROP lever is pushed forward into   the   governing   range.      The   automatic   feathering system senses loss of torque and feathers an unpowered   propeller.      Feathering   springs   feather   the propeller when it is not turning. a. Automatic Feathering.  The automatic feathering system   provides   a   means   of   immediately   dumping   oil from  the  propeller  servo  to  enable  the  feathering  spring and  counterweights  to  start  feathering  the  blades  in  the event   of   an   engine   failure.      Although   the   system   is armed by a switch on the overhead control panel (fig.    2-15),  placarded   AUTOFEATHER  TEST  -  OFF  - ARM,  the  completion  of  the  arming  phase  occurs  when both  POWER   levers   are   advanced   above   89%   Nl,   at which   time   both   annunciators   on   the   caution/advisory 2-53