TM 1-1510-224-10 row  contains  the  vertical  modes.    The  split  light  switch- indicators   illuminate   amber   for   armed   conditions   and green     for     captured     conditions.          Mode     status     is annunciated on both EADI's.  If more than one lateral or vertical   mode   is   selected,   the   flight   director   system automatically arms and captures the submode. (1)   Heading mode switch-indicator. Depressing the heading mode switch-indicator, placarded  HDG,  will  illuminate  the   ON  indicator  on  the face  of  the  switch  and  will  command  the  flight  control computer   to   follow   the   inputs   of   the   heading   marker located on the heading dial of the coupled EHSI. (2)   Navigation mode switch-indicator. Depressing the navigation mode switch-indicator, placarded  NAV,  will  cause  the  flight  control  computer  to arm,   capture,   and   track   the   navigation   signal   (VOR, LOC, TACAN, or LNAV) which has been selected as the navigation  source  for  the  EFIS.    When  approach  (APR) has  been  selected,  the  navigation  (NAV )  select  switch- indicator will annunciate lateral tracking status. (3)   Approach mode switch-indicator. Depressing the approach mode switch-indicator, placarded  APR,  will  select  the  appropriate  gains  to  arm and   capture   the   lateral   navigation   signal   for   localizer (LOC)  and  vertical  navigation  signals  for  the  glideslope. Except for an ILS, when approach is selected, the   NAV switch   will   annunciate   the   appropriate   arm   or   capture condition. (4)   Back course mode switch-indicator. Depressing    the    back    course    mode    switch-indicator, placarded  BC,  will  command  the  flight  control  computer to track the localizer back course, and will illuminate the ARM    or    CAP     indicators     on     the     switch     face     as appropriate. (5)   VOR   approach   mode   switch-indicator. Depressing the VOR approach switch-indicator, placarded VOR  APR, will select the appropriate gains for capturing   and   tracking   a   VOR   during   the   approach phase  of  flight,  and  will  illuminate  the   ARM and    CAP indicators on the switch face when appropriate. (6)   Standby mode switch-indicator. Depressing the standby mode switch-indicator, placarded    SBY,    will    remove    all    the    selected    flight director    modes,    forcing    the    command    bars    to    be removed   from   the   EADI,   and   will   illuminate   the   SBY indicator located on the switch face. (7 Indicated   airspeed   hold   mode   switch- indicator.    Depressing  the  indicated  airspeed  hold  mode switch-indicator,    placarded     IAS,     will     command     the system  to  maintain  the  current  indicated  airspeed  or  to allow a new 1.  Pitch Wheel 2.  Bank Limit Switch-Indicator 3.  Sort Ride Switch-Indicator 4.  Turn Knob 5.  Yaw Damper Switch-Indicator 6.  Autopilot Switch-Indicator 7.  Trim Annunciators A93FE00D0104 C Figure 3-21.  Autopilot Controller 3-46