TM 1-1520-238-10
3-44
Change 3
g. Entering Present Position or Destination Varia-
tion In LAT/LONG.
The variation of a destination must
be entered after the associated destination coordinates
are entered (since each time a destination is entered, its
associated variation is deleted). The order of entry for
present position is irrelevant
NOTE
If operation is to occur in a region with rela-
tively constant variation, the operator enters
variation only for present position, and the
computer will use this value throughout the
flight.
1. MODE selector switch – LATT/LON
2. DISPLAY selector switch – DEST-TGT.
3. DEST DISP thumbwheel – P, numerical, or H, as
desired.
4. Present position or destination – Enter. (Exam-
ple: Entry of N41 degrees 10.1 minutes and EO
35 degrees 50.2 minutes.) Press KYBD push-
button. Observe that display freezes and TGT
STR indicator blanks. Press KYBD pushbutton
again and observe left display blanks. To enter
latitude press keys 5, 5, 4, 1, 1, 0 and 1. To enter
longitude press KYBD pushbutton (right display
should clear) and keys 2, 2, 0, 3, 5, 5, 0, and 2
5. ENT pushbutton – Press. Entire display will
blank and TGT STR number will reappear. Dis-
play should indicate N41 degrees 10.1 EO 35
degrees 50.2.
h. Entering Ground Speed and Track.
1. MODE selector switch – BACK UP.
2. DISPLAY selector switch – GS-TK.
3. Ground speed and track – Enter. (Example: En-
ter 131 km/h and 024 degrees). Press KYBD
pushbutton. Observe that left display freezes
and TGT STR indicator blanks. To enter ground
speed press keys 1, 3 and 1. Left display blanks:
To enter track angle press keys 0, 2, and 4.
4. ENT pushbutton – Press. The entire display will
blank, and TGT STR number will reappear. Dis-
play should indicate 131 024 degrees.
i. Initial Data Entry.
Initial data entry variation
coordinates are normally done prior to takeoff. To make
the initial data entry, do the following:
1. Present position variation – Enter (para
3.14.7.f).
2. DISPLAY selector switch – DEST-TGT.
3. DEST DISP thumbwheel – P. Do not press ENT
key now.
4. ENT pushbutton – Press as helicopter is sitting
over or overflies initial fix position.
5. FLY-TO DEST thumbwheel – Desired destina-
tion location.
3.14.8 Operating Procedures.
a. Update of Present Position From Stored Des-
tination.
The helicopter is flying to a destination set by
the FLY TO DEST thumbwheel. When the helicopter is
over the destination,the computer updates the present
position when the KYBD pushbutton is pressed. This is
accomplished by using stored destination coordinates for
the destination number shown in FLY TO DEST window
and adding to them the distance traveled between the
time the KYBD pushbutton was pressed and the ENT key
was pressed.
1. DISPLAY selector switch – DIST/BRG-TIME.
2. KYBD pushbutton – Press when helicopter is
over the destination. Display freezes.
NOTE
If a present position update is not desired as
indicated by an appropriately small value of
distance to go on overflying the destination,
set the DISPLAY selector to some other
position. This aborts the update mode.
3. ENT key – Press.
