TM 55-1510-220-10 (q) Distance and time between any two waypoints: 1. WYPT          CHG          pushbutton     Press. Observe WYPT CHG and INSERT/ADVANCE pushbutton annunciator illuminates. 2. Keys corresponding to desired waypoints Press in sequence.   Observe desired   waypoint   numbers   appear   in TO-FROM   data   display   as   keys   are pressed. NOTE Do     not     press     INSERT/ADVANCE pushbutton.        This    would    cause    an immediate flight plan change. 3. Data    selector    DIS/TIME.        Observe distance     between     desired     waypoints appears  in  left  data  display  to  nearest nautical  mile.    Time  to  travel  between desired waypoints at present groundspeed     appears     in     right     data display to nearest tenth of a minute. 4. CLEAR    pushbutton    Press.        Observe INS returns to normal operation. Observe   WYPT   CHG   and   INSERT/ ADVANCE    pushbutton    annunciators extinguish.  Waypoints defining current navigation    leg    appear    in    TOFROM data display. (r) Distance to any TACAN station: 1. Data    selector    DIS/TIME.        Observe distance   to   next   waypoint   to   nearest nautical   mile   is   in   left   data   display. Time to next waypoint to nearest tenth of a minute is in right data display. 2. Keys "7" and "9" Press simultaneously. Observe    number    of    TACAN    station being   used   for   navigation   flashes   on and off in TO-FROM display.  Distance to  TACAN  station  to  nearest  nautical mile  is  in  left  data  display.    Time  to next waypoint is in right data display. 3. If in aided TACAN operation   Monitor   display.      Observe station   number   is   selected   every   15 seconds. 4. If    not    in    aided    TACAN    operation Perform steps 5 through 7. 5. WYPT CHG pushbutton Press. Observe     INSERT/     ADVANCE     and WYPT   CHG   pushbutton   annunciators illuminate.      Station   number   flashing discontinues. 6. Key indicating desired TACAN station number    Press.    Observe    number    will appear in left digit location of TOFROM data display. NOTE If wrong key is pressed, press CLEAR;  displays  will  revert  to  that indicated in step 2. 7. INSERT/ADVANCE pushbutton Press. Observe INSERT/ADVANCE and WYPT   CHG   pushbutton   annunciators extinguish.        The    loaded    digit    will appear  in  right  position  of  TO-FROM display and will be flashing on and off. Distance    to    that    station    to    nearest nautical    mile    appears    in    left    data display.  The right display continues to display time to next waypoint. 8. Data     selector     WIND,     momentarily. Returns INS to normal display mode. NOTE If  in  aided  TACAN  operation  and  if the     desired     station     is     not     being selected,    exit    aided    operation    per procedure:  "Switching  from  Aided  to Unaided Inertial Operation", perform steps  1  8,  and  then  return  to  aided operation per procedure: "Aided TACAN Operation". Change 2  3-64