TM  55-1510-221-10 7.  INSERT/ADVANCE  push- button  -  Press.  Observe  extra precision   display   related   to present   position   northing and easting,  to nearest meter,  appears  in  left  and right  data  displays,  respec- tively. 8.  Load  extra  precision  easting value   by   pressing   keys   in sequence,   starting   with   “E“. Example:  297  m  East  =  E 297.  Observe  easting  meters appear   in   right   data   display as  keys  are  pressed. 9.  INSERT/ADVANCE  push- button   -   Press.   Observe INSERT/ADVANCE  push- button   light   remains   illumi- nated. 10.   Load   extra   precision   north- ing  value  by  pressing  keys  in sequence,   starting   with   “N“ or “S”. Example:  901  m North  = N  901.  Observe Northing  meters  appear  in left  data  display  as  keys  are pressed.  The  value  is  always a d d e d    t o    n o r m al value regardless   of   which   key (N/S)  is  pressed  to  initiate entry.   Normal   entry   estab- lishes  the  hemisphere. NOTE The  “W”  key  may  be  used  to  initiate  east- ing  entries;  however,  the  computer  will always  interpret  such  entries  as  an  “E“ input. NOTE The  extra  precision  values  are  always added  to  normal  values. NOTE Any   data   inserted   when   HOLD   pushbut- ton  light  is  not  illuminated  will  be rejected   by   computer. 11. INSERT/ADVANCE  push- button   -   Press.   Observe INSERT/ADVANCE and HOLD  pushbutton  lights remain   illuminated.   North position  error  and  east  posi- tion  error  in  kilometers  will appear  in  left  and  right  data displays,   respectively. 12. If   WARN   light   illuminates, proceed   to   step   13;   other- wise  proceed  to  step  9  in procedure:  “Extra  Precision Geographic   Present   Position Check  and  Update.“ 13. Data  selector  -  DSRTK/STS. Observe  action  code  “02“ and   malfunction   code   “49“. This  indicates  radial  error between  loaded  position  and INS   position   exceeds   62 kilometers.   Operator   must evaluate  possibility  that  INS is  in  error  or  reference  point position  is  incorrect.  It  is possible   to   force   INS   to accept   updated   position   by setting  data  selector  to  UTM POS  and  proceeding  to  step 10  of  procedure:  “Extra  Pre- cision   Geographic   Present Position Check 14. If  updating  is  to  be  rejected -   Press   HOLD   pushbutton. Observe HOLD and INSERT/ADVANCE    push- button  lights  extinguish.  INS returns   to   normal   operation. (d.)  Position  update  eradication: NOTE This   procedure   is   not   considered   com- mon.  Its  use  is  limited  to  those  times where  an  operational  error  has  resulted  in an  erroneous  position  fix. 1. Data  selector  -  DSRTK/STS. 2.    Key    “1“    -    Press.    Observe INSERT/ADVANCE    push- button   light   illuminates, 000001  appears  in  right  data display. 3.  INSERT/ADVANCE  push- button   -   Press.   Observe INSERT/ADVANCE    push- button   light   extinguishes. Within  30  seconds,  data  dis- plays   return   to   normal   with “0“   (normal   inertial   mode) 3-69