2. HOLD pushbutton - Press.
Observe HOLD pushbutton
light illuminates, latitude
and longitude of present
inertial position to a tenth of
degree appear in left and
right data displays, respec-
tively.
NOTE
While HOLD pushbutton light is extin-
guished, TACAN updates are inhibited.
3. INSERT/ADVANCE push-
button - Press. Observe arc-
second related to present
inertial position latitude and
longitude, to nearest tenth of
a second, appears in left and
right data displays, respec-
tively.
4. HOLD pushbutton - Press.
Observe INS returns to nor-
mal operation and HOLD
pushbutton
light
extin-
guishes.
display:
(o.) UTM present inertial position
1.
Data selector - UTM WY
PT.
2. HOLD pushbutton - Press.
Observe HOLD pushbutton
light illuminates. Northing
and zone with easting of the
present inertial position in
kilometers appear in left and
right data displays, respec-
tively.
NOTE
While HOLD pushbutton light is illumi-
nated, TACAN updates are inhibited,
3. INSERT/ADVANCE push-
button - Press. Observe extra
precision values related to
present
inertial
position
northing and easting, to
nearest meter, appear in left
and right data displays,
respectively.
4. HOLD pushbutton - Press.
Observe INS returns to nor-
TM 55-1510-221-10
ma1 operation and HOLD
pushbutton
light
extin-
guishes.
(p.) Distance and time to waypoint
other than next waypoint:
1.
WYPT CHG pushbutton -
Press. Observe WYPT CHG
and
INSERT/ADVANCE
pushbutton light illuminates.
2. Key “0“ - Press. Observe
“FROM“ side of FROM-TO
data display changes to “0“.
3.
Key
corresponding to
desired waypoint - Press.
O b s e r v e “ T O “ s i d e of
FROM-TO data display
changes to desired waypoint
number.
NOTE
Do not press INSERT/ADVANCE push-
button. This would cause an immediate
flight plan change.
4.
5.
Data selector - DIS/TIME.
Observe distance to desired
waypoint appears in left data
display to nearest nautical
mile. Time to reach desired
waypoint at present ground-
speed appears in right data
display to nearest tenth of a
minute.
CLEAR pushbutton - Press.
Observe INS returns to nor-
mal
operation.
Observe
INSERT/ADVANCE
and
WYPT CHG pushbutton
lights extinguish. Waypoints
defining current navigation
leg appear in FROM-TO dis-
play.
(q.) Distance and time between any
two waypoints:
1. WYPT CHG pushbutton -
Press. Observe WYPT CHG
and
INSERT/ADVANCE
pushbutton lights illuminate.
2. Keys
corresponding to
desired waypoints - Press in
sequence. Observe desired
waypoint numbers appear in
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