b. Conventional Uses:
If an erroneous magnetic variation is en-
tered into SP1, the aircraft heading scale
and the HSI will also indicate that amount
Entries of magnetic headings greater
than 360 or a magnetic variation entered
greater than 179.9 will be ignored. The
message ERROR will be displayed on
the upper left of the display field prompt-
ing the operator to re-enter valid data
(1) Magnetic variation.
Use E for East and W
for West, as appropriate.
(2) Grid Convergence
Use E for East and
W for West, as appropriate. Data may be obtained from
G-M angle diagram on UTM maps if applicable.
Use the same codes utilized by
Use for North and S for South, as
4.17.2 Waypoint/Targeting Coordinate Data Stor-
Up to ten sets of coordinate data may be stored in
the FCC at anytime. Two methods can be used to store
coordinate data; these are either the data entry keyboard,
or by use of the store (ST) position of the UPDT/ST switch
on the ORT LHG.
The coordinate data are displayed as four pages of a
coordinate data menu. The various pages may be paged
by using the SPACE key on the DEK. An example page is
0 11S QG51285172A +0820
1 NO DATA
2 NO DATA
a. Store Coordinate Data Using DEK.
data input the appropriate coordinate data address. The
cursor will jump to the first position for data entry, i.e., grid
zone. Either input the specific grid zone or use the SPACE
key for automatic entry if the coordinate data grid zone is
the same as the aircrafts current present position of the
100 KM ID; either input the data or use the SPACE key
followed by the eight or sixdigit coordinates. Pressing the
SPACE key will automatically enter the A for the altitude.
If the altitude of the coordinate data is above sea level di-
rectly input the numbers; if necessary a leading zero is re-
quired. The plus sign will be automatically entered; if coor-
dinate data is below sea level the minus sign must be
input prior to the numeric value.
If a particular storage location has no data the message
NO DATA will be shown. If it is desired to clear a specific
storage location, key in the letter C followed by the desired
coordinate data storage location address. The location
will be cleared and the message NO DATA will be dis-
b. Storing Coordinate Data Using UPDT/ST
1. Waypoint/target index Desired storage loca-
2. Enter range, aircraft to waypoint/target.
Range to geographic feature or object must
be input to the FCC. This may be accom-
plished by three means: 1. Manual range in-
put through the keyboard (determined from
a map or by estimation); 2. Automatically
calculated range based on LOS angles from
selected sight; 3. Laser range input by firing
the laser after placing reticle on feature or
object (This is the most accurate range
3. Place reticle of selected sight on the geographic
feature or object.
4. UPDT/ST ST (Waypoint/target coordinate
data will be automatically calculated and placed
in the location specified by the index.)
4.17.3 Waypoint/Targeting Position Update.
This subsystem of the waypoint/targeting
calculates the present position of the heli-
copter based on previously stored coordi-
nate data. The update present position is
stored within the FCC and NOT automati-
cally sent to the doppler navigation system.
a. Position Update.
1. Waypoint/target indexer index of location of
previously stored coordinate data.
2. Enter range, helicopter to coordinate data. See
explanation under storing coordinate data [para