TM 55-1510-222-10
coordinates, with nothing data in kilometers in left
display and easting data in kilometers in right display.
The extra precision display indicates in meters.
(j) UTM WY PT. Displays or enters way-point and
TACAN station data in UTM coordinates. Also enables
loading and display of spheroid coefficients if GRID and
DISP keys are pressed simultaneously.
(14) Dim knob. Controls intensity of CDU key
annunciators and displays.
(15) 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.
d. INS - Normal Operating Procedures.
NOTE
The following data will be required
prior to operating the INS: latitude
and
longitude
(Geographical)
or
Universal Transverse Mercator (UTM)
coordinates of aircraft during INS
alignment.
This
information
is
necessary
to
program
the
INS
computer
during
alignment
procedure.
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.
CAUTION
Ensure that cooling air is available to
navigation unit before turning the INS
on.
NOTE
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.
1. Applicable circuit breakers Check
depressed.
2. Mode selector switch (FIG. 3-22) -
ALIGN. Confirm following:
a. TO-FROM display (FIG. 3-23)
indicates 1 2..
b. INSERTI/ADVANCE pushbutton
annunciator (CDU) illuminates.
c. BAT annunciator (FIG. 3-22)
illuminates for approximately 12 seconds at alignment
state 8, then extinguishes.
3. Dim knob (C'DU) Adjust for optimum
brightness of CDU displays.
4. AUTO-MAN TEST switch (CDU)
AUTO.
5. Data selector (CDU) L/L POS or UTM
POS, as desired.
Observe coordinates of last present position prior to
INS shutdown appear in data displays.
NOTE
·
Aircraft must not be towed or taxied
during INS alignment. Movement of
this type during alignment causes
large navigation errors. If aircraft is
moved
during
alignment,
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.
6. AUTO-MAN TEST switch (CDU) Press
and hold for test. Confirm following
on CDU:
7. Left and right data displays indicate
88° 88.8 N/S and 88° 88.8 E/W
respectively.
8. TO-FROM display indicates 8.8.
9. The following pushbuttons and
annunciators illuminate: ROLL LIM,
HOLD, INSERT/ADVANCE, WYPT
CHG, ALERT, BAT (on CDU and
MSU), WARN, READY NAV and
WYPT on pilot's HSI.
10. AUTO-MAN TEST switch (CDU)
Release. Confirm data displays
indicate
coordinates
in
computer
memory.
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