TM 55-1510-222-10
e.
Status data block (status including
DOP's and FOMN)
3-29.
USE OF GPS FOR CHAALS.
Not applicable.
3-30.
NAVIGATION CONCEPT
Not applicable.
Section IV. RADAR AND TRANSPONDER
3-31.
WEATHER RADAR SET (AN/APN-215).
a.
Description. The weather radar set (fig. 3-24),
provides a visual sweep, 120 ° around the nose of the
aircraft, extending to a distance of 240 nautical miles.
The presentation on the screen shows the location of
potentially dangerous areas, such as thunderstorms and
hailstorms, in terms of distance and azimuth with
respect to the aircraft. The radar is also capable of
ground mapping operations. The weather radar set is
protected by a 7 1/2-ampere RADAR circuit breaker
located in the overhead circuit breaker panel (fig. 2-6).
b.
Controls/Indicators and Functions.
(1) GAIN control. Used to adjust radar receiver
gain in the MAP mode only.
(2) STAB OFF switch. Push type on/off switch.
Used to control antenna stabilization signals.
(3) Range switches. Momentary action type
switches. When pressed, clears the screen and
increases or decreases the range depending on switch
pressed.
(4) TILT control. Varies the elevation angle of
radar antenna a maximum of 15 degrees up or down
from horizontal attitude of aircraft.
(5) 60° switch. Push type on/off switch. When
activated, reduces antenna scan from 120°
to 60
degrees.
(6) TRACK switches. Momentary action type
switches. When activated, a yellow track line extending
from the apex of the display through top range mark
appears and moves either left or right, depending on the
switch pressed. The track line position will be displayed
in degrees in the upper left corner of the screen. The
line will disappear approximately 15 seconds after the
switch is released. It will then automatically return to 0
degrees.
(7) HOLD switch. Push type on/off switch.
When activated, the last image presented before
pressing the switch is displayed and held. The word
HOLD will flash on and off in the upper left corner of the
screen. Pressing the switch again will update the
display and resume normal scan operation.
(8) Function switch. Controls operation of the
radar set.
(a) OFF. Turns set off.
(b) STBY. Places set in standby mode.
This position also initiates a 90-second warm-up delay
when first turned on.
(c) TEST. Displays test pattern to check
for proper operation of the set. The transmitter is
disabled during this mode.
(d) ON. Places set in normal operation.
(9) MODE switches. Momentary action type
switches. Pressing and holding either switch will display
an information list of operational data on the screen.
The data heading will be in blue, all data except present
data will be in yellow, and present selected data will
show in blue. The three weather levels will be displayed
in red, yellow, and green. If WXA mode has been
selected, the red bar will flash on and off. If the switch
is released and immediately pressed again, the mode
will increase or decrease depending on switch pressed.
When either top or bottom mode is reached, the
opposite switch must be pressed to further change the
mode.
(10)
NAV switch. If pressed with the INS
operating and the weather radar operating in a weather
depiction mode, the screen will display INS waypoints
that are located within the range displayed and within
the degree of coverage left or right of the present
heading of the aircraft.
(11)
BRT control. Used to adjust screen
brightness.
3-74
