TM 1-1510-225-10 3A-86 2.   Heading – Insert desired heading. 3.   ENTER key – Press. NOTE Cursor  moves  to  the  heading  mode  field, but it is not necessary to press ENTER. 4.   NAV key – Press to check heading. (21)   Changing To Waypoint While In Heading Select Mode. NOTE This  procedure  establishes  a  leg  between the   new   TO   waypoint   and   the   waypoint preceding it  on  the  active  flight  plan  or  a pseudo  VORTAC.    If  crosstrack  distance exceeds  125  nautical  miles,  the  HEADING mode    will    be    canceled    and    the    STRG INVALID message will be displayed. 1.   HDG key  –  Press  to  display  Heading Vector page. 2.   Line select key – Press to position the cursor over the TO waypoint. 3.   BACK  key   –  Press  to  cycle  through waypoints  on  the  active  flight  plan  or insert alternate waypoint. 4.   ENTER   key   –   Press.      If   Waypoint page appears: a.     Waypoint page coordinates – Verify or insert. b.     ENTER    key    –    Press.        Cursor moves to DTK field. 5.   DTK – Verify or insert. 6.   ENTER  key   –  Press.    OK?  ENTER message will appear. 7.   ENTER   key    –   Press   to   select   TO waypoint  and  return  to  NAV  1  page with the cursor positioned over the leg change mode field. NOTE If  the  desired  track  is  changed,  a  pseudo VORTAC is programmed.  If the DTK entry positions the aircraft on the FROM side of the   TO   waypoint,   the   leg   change   mode displayed  on   NAV  1  page  will  switch  to MAN; otherwise it remains in AUTO. (22)   Canceling  Heading  Select  Mode.    Initiate a  DIRECT  TO  procedure,  using  the     D  key,  which immediately    cancels    the    commanding    heading    or perform the following. 1.   HDG key  –  Press  to  display  Heading Vector page. 2.   Line select key – Press to position the cursor over HDG SELECT. 3.   BACK key  – Press until CANCEL? is displayed. 4.   ENTER key – Press to cancel heading vector and return to NAV 1 page. (23)   Programming An Intercept. 1.   HDG key  –  Press  to  display  Heading Vector page with cursor over the HDG field. 2.   Heading  –  Insert  desired  heading  in whole degrees, preceded by R or L,  if applicable, to indicate a turn direction. NOTE R   or   L   should   be   used   for   a   heading change greater than 180°  from the present heading.      A   T   indicates   the   system   is operating in the true heading mode. 3.   ENTER   key   –   Press.      The   cursor advances to heading mode field. 4.   BACK key – Press to select INTERCEPT?. 5.   ENTER   key    –   Press.      Cursor   will move to the TO waypoint field. 6.   BACK  key   –  Press  to  cycle  through waypoints  on  the  active  flight  plan  or insert alternate waypoint. 7.   ENTER   key   –   Press.      If   Waypoint page appears: