TM 1-1510-218-10 3C-18 If the  OBS / LEG  switch is in the OBS mode, the pilot’s  course  setting  knob  will  control  the  course  for the  KLN  90B.    The  bottom  MFD  on  the  pilot’s  side provides the selected course to the KLN 90B when it is in the OBS mode. (9)   Course  Sync  Button.    The  center  push button  on  the  course  source  control  is  a   CRS  sync button.  Pressing the  CRS sync (Direct-To) button for a VOR (VHF Omni Range) course source sets the active source’s course to the source’s bearing. (10)   CRS  1/2  Button.    The   CRS   1/2  button toggles  the  selected  navigation  course  (selected  by the Course Source Control) between #1 and #2. (11)   ARC Button.    The  center  push  button  on the  mode  selector  is  an    ARC  button.    Pressing  the ARC button toggles the EHSI display. 1.   HSI Mode.  Full 360 compass rose or HSI ARC 80 compass rose. 2.   MAP  Mode.    Map  80  arc  or  Map  full 360 compass. (12)   Range  Selector.    The  inner  knob  on  the mode  selector  selects  the  range  for  displays  where range  is  applicable.    Available  ranges  are  2.5,  5,  10, 20, 40, 80, 160, 320, and 640 nm.  Range information is  stored  in  the  control  panel  and  defaults  to  the  last selected value at power up. (13)   MODE Selector.  The  MODE select knob is  a  dual  concentric  knob  with  a  center  push  button.   The outer knob allows you to select between HSI and map modes. (14)   ADI/PFD Button.    The  ADI / PFD button on   the   display   control   panel   toggles   the   display between the basic EADI display and the Primary Flight display. (15)   Bearing   Source   Selector.    The  bearing (BRG)   button   selects   the   navigation   source   to   be displayed  on  the  EHSI  bearing  pointer.    The  aircraft bearing selections are   OFF,  FMS  1,  FMS  2,  VOR  1, TCN   1,   VOR   2,   ADF   1,   and   ADF   2.      If   a   VOR frequency  is  tuned  on  the  pilot’s  NAV  receiver,  the source becomes VOR 1. (16)   Heading (HDG) Selector.  The inner knob of  the  data  selector  is  used  to  position  the  heading bug.    When  the  heading  knob  is  moved  slowly,  a single click results in one degree heading changes.  If the    knob    is    rotated    quickly,    the    heading    setting changes numerous degrees per click. (17)   HDG   SYNC   Button.      The   center   push button on the data selector is a  HDG SYNC selection.   Pressing   the   PUSH   SYNC   button   will   automatically slew   the   selected   heading   bug   to   the   lubber   line.   When FMS 1 is the selected navigation source and the PUSH   button   is   pressed,   the   FMS  heading   bug   is displayed on the MFD and the navigation source label FMS changes to FHDG.  The FMS heading bug then syncs to the selected heading. (18)   DATA  Selector.  The   DATA  select knob is a dual concentric blind selector with a center push button.  The outer  knob provides sequential selection of   FMS   data   to   include   Groundspeed   (GS),   True Airspeed  (TAS),  Time  To  Go  to  next  waypoint  (TTG), Elapsed   Time   (ET)   from   WOW,   and   off-no    data displayed. (19)   Cursor Reset. The cursor reset (CURSOR RST) button resets the cursor to the aircraft symbol. 3C-14.  ELECTRONIC ATTITUDE DIRECTOR INDICATOR. a.   Description.    The  EADI,  Figure  3C-6,  is  an instrument  whose  primary  function  is  to  display  the aircraft’s current attitude.  It combines the functions of many    electromechanical    indicators    into    a    single electronic display.  This display consists of the Attitude Display  Indicator  (ADI)  display  page  and  the  Primary Flight  Display  (PFD).    The  default  display  format  on the EADI is the ADI format on powerup. The  ADI  presents  attitude,  comparator  warning annunciations, decision height setting, and rate of turn indicator.    Other  parameters  that  are  displayed  as  a function  of  pilot  selection  are  DH  annunciation,  Radio Altitude,   Rising   Runway,   Vertical   Deviation   (GS   or VNAV),   Speed   Deviation,   Flight   Director  Command Bars   (V   Bars),   Aircraft   Symbol,   Lateral   Deviation, Marker  Beacons,  Flight  Director  Annunciations,  and Course Source (Location (LOC), VOR, or FMS). b.  ADI Display Symbology. (1)   Pitch  and  roll  attitudes  are  indicated  by the    position    of    the    blue    sky    and    brown    ground relationship.    The  aircraft  symbol  is  outlined  in  white with a black interior.  Precise pitch attitude is provided by the position of the pitch scale with reference to the nose  of  the  aircraft  symbol.    Precise  roll  attitude  is provided by the position of the moving roll pointer with reference to the roll scale.  The pitch scale disappears behind the roll pointer and the lateral deviation pointer to prevent interference between the symbols.  Roll is a continuous 360 display and pitch is 90 display.