TM 55-1510-220-10 (9) COURSE  selector.    The  yellow  course  arrow is positioned on the heading dial by the course  knob to select a  magnetic  bearing  that  coincides  with  the  desired  VOR  or TACAN radial or localizer course.  Like the heading marker, the  course  arrow  rotates  with  the  azimuth  card  to  provide  a continuous   readout   of   course   error   to   the   flight   director computer. (10) Aircraft   symbol.      A   fixed   aircraft   symbol corresponds   to   the   longitudinal   axis   of   the   aircraft   and lubberline markings.  The symbol shows aircraft position and heading with respect to a radio course and the azimuth card. (11) Lateral deviation bar.  This bar represents the centerline  of  the  selected  VOR,  TACAN  or  localizer  course. The  aircraft  symbol  shows  pictorially  actual  aircraft  position in relation to this selected course. (12) HDG selector.  The heading marker (heading bug)   is   positioned   on   the   rotating   azimuth   card   and   the heading   knob   sets   pilot   selected   compass   heading.      The heading    marker    rotates    with    the    azimuth    card    so    the difference between the marker and the fore lubber line index is  the  amount  of  heading  error  applied  to  the  flight  director computer.    In  the  heading  mode,  the  FDI  vertical  command bar  will  display  the  required  bank  commands  to  bring  the aircraft onto and maintain the selected heading. (13) Course deviation dots.  In VOR, TA* CAN or INS   operation,   each   dot   represents   five   degrees   deviation from   centerline.      In   ILS   operation,   each   dot   represents   I degree deviation from centerline. (14) GS    flag.        Indicates    that    the    information displayed by the glideslope pointer is invalid and should not be used. (15) Glideslope  pointer.    Indicates  deviation  from correct glideslope during ILS approach. (16) Fixed  azimuth  marks.    Fixed  azimuth  marks are fixed at 450 bearings throughout 360 degrees of compass card for quick reference. (17) Pilot's  course  indicator  selector  switch  (fig. 2-30).  Selects desired source of data for display on pilot's HSI and input to autopilot flight computer. (a) VOR   1.      Selects   data   from   VOR   1 system. (b) VOR   2.      Selects   data   from   VOR   2 system. (c) TACAN.      Selects   data   from   TACAN system. (d) INS.  Selects data from INS. (18) Compass  selector  switch  (fig.    2-30).  Selects desired  source  of  magnetic  heading  data  for  display  on  HSI compass card. (a) No.1.  Selects data from No.1 compass. (b) No.2. Selects data from No.2 compass; c.  Controls/Indicators and Functions, Copilot's HSI. NOTE If  both  the  pilot  and  copilot  course indicator   switches   are   in   the   same position,  the  pilot  has  sole  control  of course  select  functions.    The  copilot can   only   monitor   deviation   displays from  the  selected  system.    A  PILOT SELECT  annunciator  will  illuminate to  notify  the  copilot  that  both  pilots have selected the same receiver as the pilot.    Both  the  pilot  and  copilot  can select  INS  at  the  same  time  with  no annunciator illuminated NOTE When  the  pilot  has  selected  INS,  the copilot  has  the  option  to  select  either the  VOR-I,  VOR-2,  TACAN  or  INS, to control the copilot's HSI. (1) Heading  marker.    Indicates  heading  selected by HDG knob. (2) COMPASS  flag.    Indicates  that  the  heading information displayed is invalid and should not be used. (3) Lubber  line.    This  pointed  fixed  index  mark aligns  with  the  aircraft  symbol  to  indicate  aircraft  magnetic heading on the azimuth card. (4) Course arrow.   Indicates  VOR  or  TA-I  CAN course selected COURSE knob. (5) Rotating azimuth card.   The rotating azimuth card  rotates  throughout  360  degrees.    The  rotating  azimuth card    displays    slaved    gyro    stabilized    magnetic    compass information.    The  azimuth  ring  is  graduated  in  five-degree increments. Change 2 3-24