190-00728-04 Rev. A
Embraer Prodigy® Flight Deck 100 Pilot’s Guide
363
HAZARD AVOIDANCE
PRACTICAL APPLICATION USING THE BASIC TILT SETUP
Withtheantennatiltsetas previouslydescribed,anydisplayedtargetreturn shouldbescrutinizedwhen
ying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at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.
Iftheaircraftis above29,000feet,be cautiousofany targetreturnthatgets towithin30nautical miles.
Thisislikelyathunderstormthathasatophighenoughthattheaircraftcannotyoveritsafely.
Iftheaircraftaltitudeis15,000feetorlower,settingthedisplayedrangeto60milesmaybemorehelpful.
Closelymonitoranythingthatentersthedisplay.
Also,aftersettingupthe antennatiltangleas describedpreviously,groundreturnscanbemonitored for
possiblethreats.Therelationshipbetweenantennatiltangle,altitude,anddistanceisonedegreeoftiltequals
100 feet of altitude for every one nautical mile.
Vertical Change of Radar Beam (feet)
Change in Antenna Tilt
10 nm
0
1000
2000
3000
4000
1000
2000
3000
4000
-1°
0°
-2°
-3°
-4°
+1°
+2°
+3°
+4°
Figure 6-55 Vertical Change in Radar Beam per Nautical Mile
Therefore,withthe antenna tiltset sothat thebottom ofthe beamis four degreesbelow parallelwith
theground,a targetreturnat 10nmis approximately4,000feet belowtheaircraft; at20 nm,8,000feet;
at50nm,20,000feet.Inotherwords, atthistiltsetting,agroundreturn(suchas amountainpeak)being
displayedat10nmwouldhaveamaximumdistancebelowtheaircraftof4,000feet.Agroundtargetreturn
beingdisplayedat5nmwouldhaveamaximumdistancebelowtheaircraftof2,000feet.
ThissetupprovidesagoodstartingpointforpracticaluseoftheGWX68.Therearemanyotherfactorsto
consider in order to become proficient at using weather radar in all situations.