TM 1-1510-218-10 3-73 route  between  two  other  waypoints  in  the  flight  plan.   The  point  where  the  reference  waypoint  lies  on  the great circle route is the point where the route passes closest  to  a  pilot-designated  point.    Refer  to  Figure 3-103. NOTE The   waypoint   that   is   used   to   create   the reference waypoint may be in the published or user database.  This waypoint must  be  located  relative  to  the  flight  plan such     that     it     is     possible     to     draw     a perpendicular  line  from  this  waypoint  to  a segment of the flight plan. ² ² ² ² KDAL BUJ TXKA KLIT TXK 330^o 32.9NM N Figure 3-103.  Pilot Designated Point 1.   Select the reference waypoint page (REF) on the right side, Figure 3-104.    If  a  flight plan page is not displayed on the left side, the REF page displays, "DISPLAY DESIRED - FPL ON - LEFT PAGE." FPL 2 USE? INVRT?   1:KDAL   2:BUJ   3:KLIT   4: REF E N R   -   L E G ENTER REF WPT: Figure 3-104.  Reference Waypoint 2.   Display  the  desired  flight  plan  on  the  left  side.   The  reference  feature  may  be  used on the active flight plan or on any of the 25 numbered flight plans that contain at least two waypoints. 3.   Press the right CRSR button to turn on the right cursor function. 4.   Use the RIGHT INNER and outer knobs to enter the identifier of the desired waypoint, Figure 3-105. CRSR E N T USE? INVRT?   1:KDAL   2:BUJ   3:KLIT   4: FPL 2 ENTER REF WPT:  TXK ENR  -  LEG Figure 3-105.  Desired Waypoint 5.   Press    the    ENT    button    to    display    the waypoint    page    for    the    waypoint    just entered. 6.   Press the  ENT button again to display the waypoint    page    for    the    newly    created reference   waypoint.      The  waypoint  that was used to create the reference waypoint is automatically inserted into the REF field.   The   radial   and   distance   as   well   as   the latitude  and  longitude  are  also  displayed.   The  left  side  of  the  screen  shows  where the  reference  waypoint  will  be  inserted  in the flight plan. The KLN 90B automatically names the reference waypoint  by  appending  the  first  available  alphabetic character   to   the   identifier   of   the   waypoint   used   to define  the  reference  waypoint.    TXK  becomes  TXKA, etc.    Refer  to  Figure   3-106.    If  TXK  is  used  again  to create  a  second  reference  waypoint  in  another  flight plan, this second reference waypoint would be named TXKB.      If   a   reference   waypoint   is   created   using   a waypoint    with    a    five-character    identifier,    the    fifth character   will   be   dropped,   e.g.,   DUSTT   becomes DUSTA.