TM  55-1510-221-10 10. 11. 12. 13. INSERT/ADVANCE    push- button  -  Press.  Observe  arc- seconds  related  to  present position  latitude  and  longi- tude,   to   nearest   tenth   of   a second,  appear  in  left  and right   data   displays,   respec- tively. Load  related  arc-second  val- ues  for  latitude  in  sequence, starting   with   “N“.   Example: 35.8°  North  =  N  358. INSERT/ADVANCE  push- button -   Press.   Observe INSERT/ADVANCE and HOLD   pushbuttons   remain illuminated.) Load  related  arc-second  val- ues for l o n g i t u d e   in sequence,   starting   with   “E“. Example:    20.1°    East    =    E 201. NOTE Extra  precision  values  are  added  to  nor- mal   values   and   normal   displays   are   not rounded  off. NOTE Normal    latitude-longitude    coordinates must  always  be  loaded  prior  to  extra  pre- cision  values. NOTE Directions  “N”  or  “S“  and  “E”  or  “W” are   established   during   normal   coordinate entry.  Either  key  may  be  used  to  initiate entry  during  extra  precision  loads  and values  will  be  added  to  extra  precision values   without   affecting   direction. NOTE It  is  characteristic  of  the  computer  display routine  to  add  0.2  arc-seconds  to  any  dis- play  of  59.9  arc-seconds.  Value  in  com- puter  is  loaded  by  operator. 14.  Proceed  to  step  6  in  proce- dure: “Normal   Geographic Present  Position  Check  and Update.“ update: (c.) UTM  present  position  check  and UTM  data  may and,   until   final reloaded. 1. 2. NOTE be  loaded  in  any  order entry,  a  value  may  be Data   selector   -   UTM   POS. Observe  UTM  coordinates of  present  position  appear  in data  displays. HOLD  pushbutton  -  Press (when  aircraft  passes  over known  position  reference.) Observe  HOLD  pushbutton light  illuminates.  Coordi- nates   in   data   display   freeze at values   present   when HOLD   pushbutton was pressed. NOTE While   HOLD   pushbutton   light   is   illumi- nated,   TACAN,   GPS   and   data   link updates   are   inhibited. 3. 4. 5. 6. Load  zone  and  easting  by pressing   keys   in   sequence, starting   with   “E”.   Example: Zone  16,  425  km  East  = E16  425.  Observe  zone  and easting   in   kilometers   appear in  right  data  display  as  keys are  pressed. INSERT/ADVANCE    push- button -  Press.  Observe INSERT/ADVANCE    push- button   light   remains   illumi- nated. Load   northing   by   pressing keys   in   sequence,   starting with  “N”  or  “S”  to  indicate north  or  south  hemisphere. Example:  North  4749  km  = N   4749.   Observe   northing kilometers   appear   in   left data   display   as   keys   are pressed. INSERT/ADVANCE    push- button -  Press.  Observe INSERT/ADVANCE    push- button   light   remains   illumi- nated. 3-68