Garmin G1000 King Air C90GT - Manual (Page 340)

Garmin G1000 Pilot’s Guide for the Hawker Beechcraft C90A/GT 190-00663-01 Rev. A 326
HAZARD AVOIDANCE
SY
STEM
O
VER
VIEW
FLIGHT
INSTRUMENTS
EIS
AUDIO P
ANEL
& CNS
FLIGHT
MANA
GEMENT
HAZARD
AV
OID
ANCE
AFCS
ADDITIONAL FEA
TURES
APPENDICES
INDEX
MAXIMUM PERMISSIBLE EXPOSURE LEVEL (MPEL)
The zone in which the radiation level exceeds the US Government standard of 1 mW/cm2 is the semicircular
area of at least 11 feet from the 12-inch antenna. All personnel must remain outside of this zone. With a
scanning or rotating beam, the averaged power density at the MPEL boundary is significantly reduced.
11’ for 12”
antenna
MPEL
Boundary
Figure 6-48 MPEL Boundary
bASIC ANTENNA TILT SETUP
The following discussion is a simple method for setting up the weather radar antenna tilt for most situations.
It is not to be considered an all encompassing setup that works in all situations, but this method does provide
good overall parameters for the monitoring of threats. Ultimately, it is desired to have the antenna tilted so that
the bottom of the radar beam is four degrees below parallel with the ground. The following example explains
one way of achieving this.
With the aircraft flying level, adjust the antenna tilt so ground returns are displayed at a distance that equals
the aircraft’s current altitude (AGL) divided by 1,000. For example, if the aircraft is at 14,000 feet, adjust the
tilt so the front edge of ground returns are displayed at 14 nautical miles. Note this antenna tilt angle setting.
Now, raise the antenna tilt 6 degrees above this setting. The bottom of the radar beam is now angled down 4º
from parallel with the ground.
PRACTICAL APPLICATION USING THE bASIC TILT SETUP
With the antenna tilt set as previously described, any displayed target return should be scrutinized when
flying at altitudes between 2,000 and 30,000 feet AGL. If the displayed target advances on the screen to within
5 nautical miles of the aircraft, avoid it. This may be either weather or ground returns that are 2,000 feet or less
below the aircraft. Raising the antenna tilt 4 degrees can help separate ground returns from weather returns in
relatively flat terrain. This aligns the bottom of the radar beam parallel with the ground. Return the antenna
tilt to the previous setting after a few sweeps.