TM 55-1510-219-10 POS, L/L WYPT, UTM POS, UTM WYPT and DSRTK/STS) also allow data to be loaded into data display then inserted into computer memory. TK/GS Displays aircraft track angle in left display and ground speed in right display. HDG/DA Displays aircraft true heading in left display and drift angle in right display. XTK/TK Displays cross track distance in left display and track angle error in right display. L/L POS Displays or enters present air- craft position latitude in left data display and longitude in right data display.  Both displays indicate degrees and minutes to nearest tenth of a minute. This  position  also  enables  the  insertion  of  present position    coordinates    during    alignment    and    present position updates. L/L WY  PT Displays or enters waypoint and TACAN station data, if used in conjunction with the waypoint/ TACAN selector. This   position   will   also   cause   display   of   inertial present position data when the HOLD key is illuminated. DIS/TIME Displays distance from aircraft to TACAN station or any waypoint, or between any two waypoints in left display.  Dis- plays time to TACAN station or any waypoint, or between any two waypoints, in right display. WIND Displays wind direction in left display and wind speed in right display, when  true airspeed is greater than the Air Data System lower limit (115-400 KIAS). DSRTK/STS Displays desired track angle to nearest degree in the left data display, and INS system status in right data display. UTM POS Displays or enters aircraft posi- tion in Universal Transverse Mercator (UTM) coordinates, with northing data in kilometers in left display and easting data in kilometers in right display. The extra precision display shows meters. UTM WYPT Displays or enters waypoint and TACAN station data in UTM coordinates.  Also enables load- ing and display of spheroid coef- ficients if GRID and DISP keys are pressed simultaneously. Dim knob Controls intensity of CDU  key lamps and displays. Waypoint/DME Thumbwheel switch, used to se- selector lect waypoints for which data is to be inserted or displayed. Waypoint station "O" is for dis- play only and cannot be loaded with usable data. c. INS - Normal Operating Procedures. NOTE The  following  data  will  be  required  prior  to operating the INS: Local magnetic variation, latitude and longitude or Universal Transverse   Mercator   (UTM)   coordinates   of aircraft during INS alignment. This information is necessary to program the INS computer during alignment procedure. NOTE When    inserting    data    into    INS    computer, always  start  at  left  and  work  to  right.    The first    digit    inserted    will    appear    in    right position of applicable display.  It will step to left as each subsequent digit is entered. The degree   sign,   decimal   point,   and   colon   (if applicable) will appear automatically. (1) Preflight procedures. CAUTION Insure    that    cooling    air    is    available    to navigation unit before turning the INS on. NOTE The INS requires an aircraft compass system to   provide   accurate   navigational   data   and mission data.  The compass system selected with the copilot's compass select switch will provide information to the INS platform. 3-46