Present position at the time the pushbutton
is released is automatically stored and the destination
location is that which was displayed in the target store
indicator (position 6, 7, 8 or 9) immediately before press-
ing the TGT STR pushbutton.
b. Method 2.
MODE selector UTM or LAT/LONG, de-
pending on coordinate format desired.
DISPLAY selector DEST/TGT.
DEST DISP thumbwheel P.
KYBD pushbutton Press when over flying
potential target. Display should freeze.
Do not press ENT key while DEST DISP
thumbwheel is at P.
If it is desired to store target, turn DEST
DISP thumbwheel to destination location desired and
press ENT key.
If it is not desired to store target, place DIS-
PLAY selector momentarily to another position.
3-3-28. Transferring Stored Target Coordinates from
One Location to Another.
The following procedure allows 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
Throughout this procedure, range, time-to-
go, bearing and left/right steering data are
computed and displayed for the destination
selected via the FLY-TO-DEST thumbwheel.
a. DISPLAY selector DEST/TGT.
b. DEST DISP thumbwheel 7.
c. KYBD pushbutton Press.
d. DEST DISP thumbwheel 2.
e. ENT key Press.
3-3-29. Transferring Variation from One Location to
The procedure to transfer variation data to the same
location where the associated stored target coordinates
has been transferred is the same as in previous para-
graph. Transferring Stored Target Coordinates from One
Location to Another, except that the DISPLAY selector is
placed at SPH/VAR.
3-3-30. Dead Reckoning Navigation.
As a BACKUP mode, dead reckoning navigation can be
done using ground speed and track angle estimates pro-
vided by the operator.
a. MODE selector BACKUP.
b. DISPLAY selector GS/TK.
c. Best estimate of ground speed and track angle
Enter via keyboard.
d. Set MODE selector to any position to abort this
3-3-31. Operation During and After Power Interrup-
During a DC power interruption inflight, or when all heli-
copter power is removed, the random access memory
(RAM) (stored destination and present position) data is
retained by power from an 8.4 volt DC dry cell battery.
This makes it unnecessary to reenter any navigational
data when power returns or before each flight. If the
battery does not retain the stored destination data during
power interruption the display will indicate an EN when
power returns. This indicates to the pilot that previously
stored data has been lost, and that present position,
spheroid/variation, and destinations must be entered.
The computer, upon return of power, resets present posi-
tion variation to E000.0, destination and associated vari-
ations to a non-entered state, sets wind to zero and
spheroid to CL6. The following data must be entered
following battery failure:
b. Present position variation.
c. Present position.
d. Each destination and its associated variation.
3-3-32. Stopping Procedure.
MODE selector OFF.
3-3-33. Horizontal Situation Indicator (HSI).
Two horizontal situation indicators (HSI) (fig. 3-3-6), one
on each pilots instrument panel, are installed. Each indi-
cator can display helicopter heading, FM homing, and
position relative to a selected course or bearing. Also,
during an ILS approach, the indicator displays helicopter
position relative to the glide slope and localizer. The auto-
matic heading select feature of the AFCS is also con-
trolled through the HSI. Selection of navigational equip-
ment to be displayed on each HSI is controlled through
the HSI MODE SELECT panel on each instrument panel
below each HSI. Each HSI receives electrical power from
three different sources (copilots sources are in paren-
theses): 28 volt DC from the No. 2 (No. 1) DC bus through
the NAV PLT (COPLT) HSI MODE SEL circuit breaker,
115 volt AC from the No. 2 (No. 1) AC bus through the
NAV PLT (COPLT) HSI circuit breaker, and 26 volt AC