TM 1-1510-218-10 3-20 2.   Press the appropriate CRSR button     to     turn     on     the     cursor function if it is not already on. 3.   Enter   the   desired   altitude   in   the SEL field. 4.   Use  the  outer  knob  to  move  the cursor to the offset field adjacent to the active waypoint identifier.   Entering  an  offset  allows  reaching the    desired    altitude    a    specified distance before reaching the waypoint. Notice  that  the  bottom  of  the  NAV  4  page  now displays an angle.  To start the descent now using the displayed    descent    angle,    use    the    outer    knob    to position   the   cursor   over   the   ANGLE   field.      VNAV operation  is  initiated  by  bringing  the  cursor  over  the ANGLE field.  By leaving the cursor off of the  ANGLE  field,   the   angle   will   increase   as   flight   is   continued toward   the   waypoint.      When   the   desired   angle   is reached, position the cursor over the ANGLE field and VNAV will commence.  When VNAV begins, the top of the page displays an advisory altitude. 5.   A desired angle may be programmed.      The   CAL   4   page may     be     used     to     calculate     a descent    angle.        To    program    a descent angle: a.     Using  the  outer  knob,  move the cursor to the ANGLE field and enter the desired descent angle.  If the time to begin the descent    is    greater    than    10 minutes,    VNV    ARMED    will now  be  displayed  on  the  top line of the NAV 4 page.  If the time  is  less  than  10  minutes, the top line displays a countdown    to    the    time    to begin descent. b.     Return   to   any   desired   page for  now.    If  the  NAV  4  page was  selected  by  pressing  the altitude button, press the altitude  button  once  again  to return to the pages previously in  view.    If  the  NAV  4  page was    selected    by    using    the outer  and  inner  knobs,  insure the  cursor  function  is  off  and use the outer and inner knobs to   select   the   desired   page.   Approximately 90 seconds before  the  time  to  begin  the descent, the message prompt will flash.  The message page will    display    VNAV    ALERT.   This is notification to view the NAV   4   page   because   it   is getting   close   to   the   time   to begin the descent. c.     When the countdown reaches 0:00, the time will be replaced with an altitude advisory.   Begin the descent so that the altitude displayed on the altimeter  matches  the  altitude advisory. VNAV  on  a  flight  plan  is  virtually  identical.    The NAV  4  page  will  initially  contain  the  identifier  for  the active     waypoint.          VNAV     may     be     programmed referencing this waypoint or any waypoint in the active flight plan that is  still  in  front  of  the  aircraft's  position.   When   another   valid   waypoint   in   the   flight   plan   is entered  on  the  NAV  4  page,  the  aircraft's  lateral  flight path is not altered. (5)   NAV 5 Page.    The  NAV  5  page  provides a  navigation  graphics  presentation.    Refer  to  Figure 3-14. NAV 5   1:KMDT   2:LRP   3:MXE   4:KPHL   5: E N R   -   L E G FPL 0 123^o 40 2 3 4 Figure 3-14.  NAV 5 Page In   all   KLN   90B   installations   there   are   three common map orientations that may be selected on the NAV  5  page:  a  true  north  up  display,  a  desired  track up display, or an actual track up display.  In addition, if the   KLN   90B   is   interfaced   with   the   engine   trend monitoring   system,   a   heading   up   presentation   may also be selected.