TM 1-1510-225-10 3B-6 Electronic  Attitude  Direction  Indicator  (EADI)  and  the bottom display is configured as an Electronic Horizontal Situation Indicator (EHSI). The MFD provides all of the internal diagnostics, data     processing,     and     hardware     configuration     to provide the following display modes: (1)   HSI.    Full  compass  rose  (360)   or   HSI ARC which includes course needles, a bearing needle, heading bug, etc. (2)   Missed Approach Point.  A centered 360 Missed    Approach    Point    (MAP)    or    an    expanded compass  rose  segment  (80).    Both  of  these  modes include the current set of waypoints and course legs. (3)   ADI.    Provides  aircraft  attitude  pitch  and roll, lateral deviation, and vertical deviation. (4)   Primary  Flight  Display  (PFD).    ADI  and HSI combined on one display. (5)   Diagnostics.    Provides  Multi  Functional Display (MFD) status pages. b.  External Aircraft Controls. (1)   Reversionary  Switch.    The  reversionary switches  are  external  push  button  switches  allowing the   operator   to   place   the   EADI   information   on   the bottom  display.    The  pilot’s  switch  is  located  on  the lower left portion of the dash panel under the Turn and Slip  Indicator.    The  copilot’s  switch  is  located  on  the lower right portion of the dash panel under the Vertical Speed Indicator.  The switch has two positions: normal and   reversionary.      In   the   normal   position   the   top display is an EADI and the bottom display is an EHSI.   In the reversionary position the top display blanks and the bottom display becomes an EADI. (2)   OBS   /   LEG   Switch.      The   OBS   /   LEG  switch  places  the  FMS  2  KLN  90B  in  either  LEG  or OBS mode.  The  OBS / LEG switch is located on the top center portion of the dash panel to the right of the altitude select panel.  While in LEG mode the KLN 90B continuously updates the desired course in order to fly a   great   circle   route   between   the   FROM   and   TO waypoints.  If the leg selection is made and FMS 2 is selected  as  the  primary  navigation  source,  the  digital course  label  displays  DTK.    While  in  OBS  mode  the pilot’s   MFD   control   panel   updates   the   course   and sends the manually selected course to the KLN 90B.   If the OBS selection is made and FMS 2 KLN 90B is selected as the course source, the digital course label displays   CRS   and   reflects   the   pilot’s   control   panel course selection. (3)   EFIS #1 and EFIS #2 Power Switch.  The EFIS   #1   /   EFIS   #2   power   switch   is   a   push-button switch located on the lower left side of the dash  panel beneath the Turn and Slip Indicator.  Power is applied to the pilot’s display via   EFIS  #1 switch and power is applied to the copilot’s display via  EFIS #2 switch. (4)   DME  Hold Switch.  The  DME hold switch enables  the  DME  hold  feature  of  VOR  1.    The   DME hold   switch   is   located   on   the   CTL -32  NAV  Control Head.  The pilot’s MFD monitors the  DME hold switch and annunciates its position. (5)   COMPASS 1 and COMPASS 2 Switches.  The   COMPASS 1 switch is located on the lower  left  side  of  the  dash  panel  under  the   EFIS #1  / EFIS  #2  switch.    The   COMPASS  2  switch  is  located on  the  lower  right  side  of  the  dash  panel  under  the Vertical   Speed   Indicator.      The   compass   switches consist   of   a   gyro   FREE   /   SLAVE   switch   and   an INCREASE   /   DECREASE  (slew)  switch.    Selecting FREE on the   FREE  /  SLAVE  switch  disengages  the gyro and allows manual slewing of the compass card via   the   INCREASE   /   DECREASE   Switch.      When FREE  is  selected,  heading  validity  is  ignored.    The COMPASS 1 switches control the pilot side compass card and the COMPASS 2 switches control the copilot side compass card.  The MFD does not interface with the  slew  Switches  and  only  annunciates  the  state  of the FREE / SLAVE Switch. c.   Display Control Panel. (1)   MFD   Control   Panel.    The  MFD  Control Panel provides integrated display management via the controls   shown   in   Figure   3B-3.      Unless   otherwise noted    the    pilot’s    control    panel    drives    the    pilot’s displays,   and   the   copilot’s   control   panel   drives   the copilot’s  displays.    The  pilot  can  select  PFD  on  the display  control  panel  when  in  the  reversionary mode.   This makes the bottom display a PFD without some of the functions. Whenever either display fails it is probable that functions of that display will also fail. (2)   Display Control Panel Controls and Functions.   Listed below are  the controls found on the Control    Panel    and    their    corresponding    functions.   Refer to Figure 3B-3. WARNING