Garmin Flight Deck 100 Marine Instruments User Manual


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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.
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