TM 1-1510-225-10 3B-8 The  diagnostics  page  consists  of  MFD  status information  shown  as  a  result  of  a  Built-In-Test (BIT).   The  diagnostic  display  page  is  only  active  while  the aircraft  is  on  the  ground  and  the  Weight  On  Wheels (WOW) discrete is set. Perform  the  following  procedures  to  select  the MFD status page. 1.   Press the  MFD test button on the control panel. 2.   Press    the    ARC    button    on    the control panel to exit diagnostics. (e)  Decision   Height   (DH)   Setting.    The DH knob rotates and has  a  center  push  button.    The DH   SET   knob   is   used   to   set   the   decision   height.   Clockwise rotation increases the decision height.  The decision   height   is   displayed   in   green   following   the letters DH in the lower right corner of the ADI.  When the  radio  altitude  is  at  or  below  the  DH  setting,  the yellow letters DH appear in the right center portion of the    ADI    or    PFD    display    and    a    “Minimum”    aural annunciation  is  sounded.    Once  the  DH  annunciation appears, it is removed from the display when the radio altitude   climbs   at   least   25   feet   above   the   decision height.  If the radio altimeter system fails, the decision height  annunciator  is  removed  and  the  radio  altitude flag appears. (f)   Radio Altitude Test.  The center push button on the  DH  SET  knob  setting  is  a  radio  altitude test button.  Pushing the test button causes the radio altimeter to go into test.  While the radio altimeter is in test, the digital readout remains displayed, even when the radio altimeter validity is flagged. (g)  Course  Source  Selector.    The  blind course  select  knob  is  a  dual  concentric  knob  with  a center   push   button.      The   outside   knob   selects   the active  course  sources.    The  selections  are  FMS  or VOR.    The  selector  switch  is  knob  that  when  rotated cycles between the sources.  Used in conjunction with the  CRS   1/2  button,  the  Nav  sources  are  switched between  all  navigation  sources  (i.e.,  FMS  1/FMS 2 or VOR/VOR 2). (h)  Course Selector.    The  inner  knob  on the Course Source Control selects the desired course for the active course source.  When the knob is moved slowly, a single click will result in a 1° course change.   If   the   knob   is   rotated   quickly,   the   course   setting changes numerous degrees per click. 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. (i)   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. (j)   CRS 1/2 Button.  The  CRS 1/2 button toggles  the  selected  navigation  course  (selected  by the Course Source Control) between #1 and #2. (k)  ARC Button.  The center push button on the mode selector is an  ARC button.  Pressing the ARC button toggles the EHSI display as follows: 1.   HSI   Mode.      Full   360   compass rose   or   HSI   ARC   80   compass rose. 2.   MAP Mode.  Map 80 arc or Map full 360 compass. (l)   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. (m) 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. (n)  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. (o)  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,  VOR  2,  ADF  1, and   ADF  2.    If  a  VOR  frequency  is tuned on the pilot’s NAV receiver, the source becomes VOR 1. (p)  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.