Tilt Management (Cont.)
Tilt Management (Cont.)
38
RDR-1600 Pilot’s Guide
TM106101(8/01)
TM106101(8/01)
RDR-1600 Pilot’s Guide
39
8.3 EARLY DETECTION OF ENROUTE WEATHER
To set the Antenna Tilt to optimize the radar’s ability to quickly identify
significant weather, follow these steps:
1. Select the Wx (Weather) or WxA (Weather Alert) mode of operation.
Adjust brightness control as desired.
2. Select the 40 or 80 nm range.
3. Adjust the Antenna Tilt control down until the entire display is filled with
ground returns.
4. Slowly work the Antenna Tilt up so that ground returns are painted on or
about the outer one third of the indicator area.
5. Watch the strongest returns seen on the display. if, as they are
approached, they become weaker and fade out after working back inside
the near limit of the general ground return pattern, they are probably
ground returns or insignificant weather. If they continue strong after
working down into the lower half of the indicator, you are approaching a
hazardous storm or storms, and should deviate immediately.
6. Examine the area behind strong targets. If radar shadows are detected,
you are approaching a hazardous storm or storms, and should deviate
immediately. Regardless of the aircraft’s altitude, if weather is being
detected, move the Antenna Tilt control up and down in small increments
until the return object is optimized. At that angle, the most active vertical
level of the storm is being displayed.
Antenna Tilt Angle
Altitude (ft)
10”
12”
18”
Line-of-Sight
Range (SM)
5,000
+7.0°
+6.0°
+5.0°
87
10,000
6.0°
5.0°
4.0°
123
15,000
5.5°
4.0°
3.0°
150
20,000
4.5°
3.5°
2.5°
174
25,000
4.0°
3.0°
2.0°
194
30,000
3.5°
2.5°
1.5°
213
35,000
3.0°
2.0°
1.0°
230
40,000
2.5°
1.5°
0.5°
246
Figure 8.3-1. Weather Target
If target is shown at or beyond the line-of-sight range listed above, the
chances are good that it is a weather target.
Table 8.3-1. Antenna Tilt Control Settings
Note
+
The TILT position in
Step 4 should be that
shown in the chart.
The exact setting will
depend upon the air-
craft’s pitch altitude
and the flatness of
the terrain.
8.2 TILT PERFORMANCE CHECK
A good performance check of your radar system in flight is to lower the tilt
slowly and observe the maximum range of solid ground returns. As a rule
of thumb, this range in miles should approximate the square root of your
operational altitude.
Figure 8.2-1. Altitude vs. Range
For example, at 5,000 ft. the maximum displayed ground target range
should be about 70 nautical miles. You should perform this test on every
flight. Don’t wait until you’re penetrating severe weather to discover that
your system is not providing optimum performance.
If the radar is operating normally when you reach cruising altitude, select
the longest display range and lower the antenna tilt until ground targets are
displayed. Now, slowly raise the tilt until the ground returns disappear. This
will give you the optimum tilt setting for your cruise altitude. Each time a
new range is selected, however, the tilt control must be readjusted, down
for a shorter range, and up for a longer one.
