b. Navigate Mode.
In the navigate mode (UTM or
LATT/LONG position of the MODE selector switch), pow-
er is applied to all system components, and all required
outputs and functions are provided. Changes in present
position are computed and added to initial position to de-
termine the instantaneous latitude/longitude of the heli-
copter. Destination and present position coordinates can
be entered and displayed in UTM and latitude/longitude.
At the same time, distance, bearing and time-to-go to any
one of ten preset destinations are computed and dis-
played as selected by the FLY TO DEST thumbwheel.
c. Backup Mode.
In this mode, remembered veloc-
ity data are used for navigation. The operator can insert
ground speed and track angle with the keyboard and the
display in GS-TK position. This remembered velocity data
can be manually updated through use of the keyboard
and CDU DISPLAY selector switch in GS-TK position.
When GS-TK values are inserted under these conditions,
navigation continues using only these values.
3.14.7 Methods of Operation.
Methods of operation
are as follows:
a. Window Display and Keyboard Operation.
all data displays except UTM coordinates, the two fields
are the left and right display windows. In UTM coordinates
displays, the first field of control is the center window and
the second field is the combination of the left and right dis-
plays. When pressing the KYBD pushbutton, one or other
of the fields described above is under control. If it is not
desired to change the display in the panel section under
control, the pilot can advance to the next field of the dis-
play panel by pressing the KYBD pushbutton again. The
last character entered may be cleared by pressing the
CLR key. That character may be a symbol or an alphanu-
meric character. However, if the CLR key is pressed twice
in succession, all characters in the field under control will
be cleared, and that field will still remain under control.
b. Data Entry.
To enter a number, press the corre-
sponding key. To enter a letter, first press the key corre-
sponding to the desired letter. Then press a key in the left,
middle, or right column corresponding to the position of
the letter on the pushbutton.For Example:
To enter an L,
first press L, then either 3, 6, or 9 in the right column. The
computer program is designed to reject unacceptable
data (for example, a UTM area of WI does not exist and
will be rejected). If the operator attempts to insert unac-
ceptable data, the display will be blank after ENT is
c. Starting Procedure.
(1). Lamp Test
1. MODE selector switch LAMP TEST. All
display segments and indicator lamp should
2. DIM control Turn fully clockwise, then fully
counterclockwise, and return to full clock-
wise. All segments of the display should al-
ternately glow bright, go off, and then glow
1. MODE selector switch TEST.
Ignore the random display of alpha and
numeric characters which occurs during
the first 15 seconds. Also ignore test ve-
locity and angle data displayed after the
display has frozen. A successful test can-
not be accomplished until HARS has
If the MAL lamp lights during any mode of
operation except LAMP TEST, the CDU
MODE switch should be turned first to
OFF and then to TEST to verify the fail-
ure. If the MAL lamp remains on after re-
cycling to TEST, enter the failure of the
DNS on DA Form 2408-131 in the air-
craft log book.
After approximately 15 seconds, one of
the following displays in table 3-13 will be
observed in the left and right displays: