(b.)   Insertion   of   geographic   TACAN station data: NOTE Prior   to   pressing   INSERT/ADVANCE pushbutton,   any   incorrectly   loaded   data can   be   corrected   by   pressing   CLEAR pushbutton   and   loading   correct   data. 1. Data  selector  -  L/L  WY  PT. NOTE If  number  of  station  to  be  loaded  is  same as  number  of  TACAN  station  currently being  used,  number  in  “FROM-TO”  dis- play  will  be  set  to  “0”  when  TACAN  data is  loaded. 2.  Keys  “7”  and  “9“  -  Press simultaneously.  Observe  that number   of   TACAN   station being   used   for   navigation flashes  on and off in “FROM-TO“   display.   Data displays   indicate   coordinates of  station  selected  via  thum- bwheel. 3.  Thumbwheel  -  Set  to  num- ber   of   station   being   loaded. (Insure   thumbwheel   is   in detent.) NOTE Station  “0”  cannot  be  loaded. 4. To  load  latitude  -  Press  keys in  sequence, starting   with “N”  or  “S”  to  indicate  north or  south.  Example:  42°  54.0’ North  =  4  2  5  4  0.  Observe that INSERT/ADVANCE pushbutton   light   illuminates when  first  key  is  pressed. 5.  INSERT/ADVANCE  push- button  -  Press  Observe  push- button  light  extinguishes. 6.   To   load   longitude   -   Press keys   in   sequence,   starting with  “W”  or  ,“E”  indicating west  or  east.  Example:  87° 54.9’West   =   W  8  7  5  4  9. 7. 8. 9. 10. 11. 12. TM  55-1510-221-10 Observe that INSERT/ ADVANCE  pushbutton  light illuminates  when  first  key  is pressed, and longitude appears   in   data   display   as keys  are  pressed. INSERT/ADVANCE    push- button   -   Press.   Observe pushbutton light extin- guishes. INSERT/ADVANCE    push- button  -  Press.  Observe  that the   arc-seconds   related   to loaded   latitude   and   longi- tude,  to  nearest  tenth  of  a second,   appear   in   left   and right  data  display,  respec- tively. If  extra  precision  coordinate data  is  to  be  inserted  -Press keys   in   sequence,   starting with   “N“,   to   load   related arc-second  values  for  lati- tude.   Example:   35.8“   North =  N  358. INSERT/ADVANCE    push- button   -   Press.   Observe pushbutton light extin- guishes. To   load   related   arc-second values  for  longitude  -  Press keys   in   sequence,   starting with  “E”.  Example:  20.1” East  -  E  201. INSERT/ADVANCE    push- button   -   Press.   Observe pushbutton light extin- guishes. NOTE In above e x a m p l e ,   if INSERT/ ADVANCE  pushbutton  were  pressed,  the following  normal  display  would  appear: “42° 54.5 N” and “87° 54.3 W”. The extra precision  values  are  added  to  normal  val- ues  and  normal  displays  are  not  rounded off. NOTE The   normal   geographic   coordinates   must always  be  loaded  prior  to  extra  precision values. 3-59