TM 1-1520-238-10
Change 3
3-45
b. Update of Present Position From Land-
mark.
There are two methods for updating present posi-
tion from a landmark. Method 1 is useful if the landmark
comes up unexpectedly and the operator needs time to
determine the coordinates. Method 2 is used when a land-
mark update is anticipated.
1. Method 1.
a. DISPLAY selector switch – PP.
b. KYBD pushbutton – Press as landmark is
overflown. Present position display will
freeze. Compare landmark coordinates with
those on display.
(1) Landmark coordinates – Enter. If differ-
ence warrant an update.
(2) ENT key – Press if update is required.
(3) DISPLAY selector switch – Set to some
other position to abort update.
2. Method 2
a. DISPLAY selector switch – DEST/TGT.
b. DEST DISP thumbwheel – P. Present posi-
tion coordinates should be displayed.
c. KYBD pushbutton – Press. Observe that
display freezes.
d. Landmark coordinates – Manually enter via
keyboard.
e. ENT key – Press when overflying landmark.
f. DISPLAY selector switch – Set to some oth-
er position to abort update.
c. Left-Right Steering Signals.
Flying shortest
distance to destination from present position:
1. DISPLAY selector switch – XTK-TKE.
2. MODE selector switch – UTM.
3. To center the pointer, fly the helicopter in the di-
rection of the course deviation bar on the HSI.
d. Target Store (TGT STR) Operation.
Two meth-
ods may be used for target store operation. Method 1 is
normally used when time is not available for preplanning a
target store operation. Method 2 is used when time is
available and it is desired to store a target in a specific
DEST DISP position.
1. Method 1.
a. TGT STR pushbutton – Press when flying
over target. Present position is automatical-
ly stored and the destination location is that
which was displayed in the target store indi-
cator (position 6, 7, 8, or 9) immediately be-
fore pressing the TGT STR pushbutton.
2. Method 2.
a. MODE selector switch – UTM or LATT/
LONG, depending on coordinate format de-
sired.
b. DISPLAY selector switch – DEST-TGT.
c. DEST DISP thumbwheel – P.
d. KYBD pushbutton – Press when overflying
potential target. Display should freeze.
NOTE
Do not press ENT key while DEST DISP
thumbwheel is at P.
e. If it is desired to store the target, turn DEST
DISP thumbwheel to destination location
desired and press ENT key.
f. If it is not desired to store the target, mo-
mentarily place DISPLAY selector switch to
another position.
e. Transferring Stored Target Coordinates From
One Location to Another.
The following procedure al-
lows the operator to transfer stored target coordinates
from one thumbwheel location to another. For example: it
is assumed that the pilot wants to put the coordinates of
stored target 7 into location of destination 2.
