(h.) DSRTK/STS. Displays
track angle to nearest degree in the left data display,
and INS system status in right data display.
(i.) UTM POS. Displays or enters
aircraft position in Universal Transverse Mercator
(UTM) coordinates, with northing data in kilome-
ters in left display and easting data in kilometers in
right display. The extra precision display shows
UTM WY PT. Displays or enters
waypoint and TACAN station data in UTM coordi-
nates. Also enables loading and display of spheroid
coefficients if GRID and DISP keys are pressed
Dim knob. Controls intensity of CDU
key lights and displays.
Waypoint/DME selector. Thumbwheel
switch, used to select waypoints for which data is to
be inserted or displayed. Waypoint station 0 is for
display only and cannot be loaded with usable data.
INS - Normal Operating Procedures.
The following data will be required prior
to operating the INS: latitude and longi-
tude (Geographical) or Universal Trans-
verse Mercator (UTM) coordinates of air-
c r a f t d u r i n g I N S a l i g n m e n t . T h is
information is necessary to program the
INS computer during alignment proce-
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 Procedure.
Insure that cooling air is available to nav-
igation unit before turning the INS on.
Aircraft must be connected to a ground
power unit if INS alignment is performed
prior to engine starting. In this event, the
engines must not be started until after the
INS is placed in the NAV mode.
Applicable circuit breakers -
2. Mode selector switch (MSU, fig.
3-23) - ALIGN. Confirm follow-
FROM-TO display (CDU,
fig. 3-24) indicates 1 2.
b. INSERT/ADVANCE push-
button light (CDU) illumi-
BAT light (MSU, fig. 3-23)
mately 12 seconds at align-
ment state 8, then extin-
3. Dim knob (CDU) - Adjust for
optimum brightness of CDU dis-
(CDU) - AUTO.
Data selector (CDU) - L/L POS or
UTM POS, as desired. Observe
coordinates of last present posi-
tion prior to INS shutdown
appear in data displays.
Aircraft must not be towed or taxied dur-
ing INS alignment. Movement of this type
during alignment causes large navigation
errors. If aircraft is moved during align-
ment, restart alignment by setting mode
selector switch to STBY, then back to
ALIGN and reinserting present position.
Passenger or cargo loading in the aircraft
could cause the type of motion which
affects the accuracy of alignment. Any
activity which causes the aircraft to
change attitude shall be avoided during
the alignment period.
(CDU) - Press and hold for test.
Confirm following on CDU:
Left and right data displays indi-
cate 88°88.8 N/S and 88°88.8