TM 55-1510-220-10 8. Load   longitude   by   pressing   keys   in sequence,   starting   with   "W"   or   "E" indicating  west      or      east.      Example: 87"54.9' West = 8 7 5 4 9. 9. INSERT/ADVANCE pushbutton Press.      Observe   INSERT/ADVANCE and    HOLD    pushbutton    annunciators remain illuminated. 10. INSERT/ADVANCE pushbutton  Press. Observe  arc-seconds  related  to  present position    latitude    and    longitude,    to nearest tenth of a second, appear in left and right data displays, respectively. 11. Load    related    arc-second    values    for latitude in sequence, starting with "N". Example: 35.8" North = N 358. 12. INSERT/ADVANCE pushbutton Press. Observe INSERT/ADVANCE and HOLD pushbuttons remain illuminated. 13. Load    related    arc-second    values    for longitude   in   sequence,   starting   with "E".  Example: 20.1° East = E 201. NOTE Extra   precision   values   are   added   to normal   values   and   normal   displays are not rounded off. NOTE Normal  latitude-longitude  coordinates must  always  be  loaded  prior  to  extra precision 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   display   of   59.9   arc-seconds. Value   in   computer   is   as   loaded   by operator. 14. Proceed     to     step     6     in     procedure: "Normal   Geographic   Present   Position Check and Update." (c) UTM present position check and update: NOTE UTM data may be loaded in any order and, until final entry, a value may be reloaded. 1. Data   selector   UTM   POS.      Observe UTM   coordinates   of   present   position appear in data displays. 2. HOLD pushbutton Press (when aircraft passes  over  known  position  reference). Observe HOLD pushbutton annunciator illuminates.          Coordinates     in     data display freeze  at  values  present when HOLD pushbutton was pressed. NOTE While HOLD pushbutton annunciator is   illuminated,   TACAN   updates   are inhibited. 3. 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. 4. INSERT/ADVANCE pushbutton annunciator remains illuminated. 5. Load northing by pressing keys in sequence, starting Change 2  3-68