i. Present position data Insert.
After present position 'has been
advanced to state "7", present
position cannot be reinserted
without downmoding to STBY
and restarting alignment.
j. Data selector DSRTK/STS
(Observe that the left data display indicates the
desired track stored in computer memory and that the
right data display indicates status "-194.")
If the fourth digit from the right, in
the right data display is blank,
then a valid heading has not been
stored. Proceed with normal
k. Monitor the right data display for a
change from alignment state "9" to
alignment state "8". This will be
indicated by a reading of "--184".
l. Monitor the right data display for
malfunction codes (table 3-5).
(Loss of 26 VAC is indicated by an illuminated
WARN lamp and a reading of ".03184" in the right-hand
display. An inoperative magnetic compass system is
indicated by an extinguished WARN lamp and a reading
of ".03184" in the right-hand display.)
If above displays appear, a stored
heading alignment may not be
m. If there are malfunction codes,
PROCEDURES in this chapter.
reached, the INS will advance to the
(Observe that "---05" will appear in the STS display.)
To achieve best accuracy, engine
start and heavy loading activity
should be delayed until entry into
With the data selector in either the
L/L WY PT or UTM WY PT
position, waypoint and TACAN
station data may be loaded at any
time after turn-on. The operator
should occasionally switch the
data selector to DSRTK/STS to
monitor system status indicators
in the right data display.
(CDU) AUTO/MAN/TEST switch Press
and hold. Confirm:
1. Left and right data displays indicate
"88°88.8 N/S" and "88°88.8 E/W"
2. FROM-TO display is "8.8".
lamps illuminate: ROLL LIM, HOLD,
INSERT/ADVANCE, WYPT CHG,
ALERT, BAT (on CDU and MSU),
WARN and READY NAV.
TEST switch Release. (Observe data
displays indicate coordinates in computer memory; also
all lamps and pushbuttons lighted in step 7 except
INSERT/ADVANCE pushbutton extinguish.)
Appropriate grid coefficients Verify loaded
(if UTM coordinates are to be used.)
Verify UTM grid coefficients.
1. Data selector UTM WYPT.
2. Keys "5" and "9" Press simultaneously.
Observe FROM-TO display is blank. Earth flatness
coefficient appears in left display. The relative earth
radius, in meters, appears in right display.)
These values are retained from
turn-on to turn-on unless changed
3. Verify that values correspond to
those required for spheroid being