TM 1-1520-240-10
3-3-9
Table 3-3-2. Computer-Display Unit Data Displays
CENTER DISPLAY
LEFT DISPLAY
RIGHT DISPLAY
SWITCH POSI-
TION
DATA
RANGE
DATA
RANGE
DATA
RANGE
WIND SP/DIR
Windspeed
999 km/h
Wind Direc-
tion
359_
XTK/TKE
Crosstrack Dis-
tance Error
L/R 999.9
km
Track Angle
Error
R/L 180_
GS/TK
Groundspeeed
999 km/h
Track
359_
PP
UTM
UTM Zone
Note 2
Area/Easting
WV9999
Northing
9999
LAT/LONG
Latitude
N 84_00.0”
S 80_00.0”
Longitude
E/W
180_00.0”
DIST/BRG/TIME
Time
99.9 Min.
Distance to Go
999.9 km
Bearing
359_
DEST/TGT UTM
UTM Zone
Note 2
Area/Easting
WV9999
Note 3
Northing
9999
LAT/LONG
Latitude
N 84_00.0”
S 80_00.0”
Longitude
E/W
180_00.0”
SPH/VAR
Spheroid
Note 1
Variation
Note 4
E/W 180_
NOTES:
1. See table 3-3-3 for spheroid data codes and covered areas.
2. Numeric: 01-60.
Alpha: C-X, except I and O.
3. Typical 100 km Designator:
Column Designator: A-Z, except I and O.
Row Designator: A–V, except I and O.
4. Variation displayed is for destination indicated by DESP DISP thumbwheel.
b. MODE selector — TEST. After about 15 seconds,
left display should display GO. Ignore the random display
of alpha and numeric characters which occurs during the
first 15 seconds. Also ignore test velocity and angle data
displayed after the display has frozen. After about 15
seconds, one of the following five displays will be ob-
served in the first two character positions in the left dis-
play.
NOTE
If the MAL lamp lights during any mode of
operation except LAMP TEST, the computer-
display unit MODE switch should be set to
OFF, and then to TEST, to verify the failure. If
the MAL lamp remains on at TEST, notify
maintenance.
If the TEST mode display is MN or NG, the MODE switch
should be recycled through OFF to verify that the failure
is not a momentary one. If the TEST mode display is MN,
the data entry may be made in the UTM or LAT/LONG
mode, but any navigation must be carried on with the
system in the BACKUP mode.
DISPLAY
LEFT
RIGHT
REMARKS
GO
Display
blanks
System is operating satisfac-
torily.
GO
P
If right display is P, then pitch
or roll data is missing or in er-
ror. In this case, pitch and roll
in the computer are both set
to zero and navigation is de-
graded. Problem may be in
the vertical gyroscope or heli-
copter wing.
BU
C, R, S,
or H fol-
lowed
by a nu-
meric
code
A failure has occurred and the
system has automatically
switched to a BACKUP mode
of operation using last re-
membered velocities for na-
vigation. The operator can, as
