190-00498-07 Rev. A
Garmin G1000 Pilot’s Guide for Cessna Nav III
SYSTEM
OVERVIEW
FLIGHT
INSTRUMENTS EIS AUDIO PANEL
& CNS
FLIGHT
MANAGEMENT
HAZARD
AVOIDANCE AFCS ADDITIONAL
FEATURES APPENDICES INDEX
289
HAZARD AVOIDANCE
Displaying NEXRAD weather information:
1) Press the MAP Softkey (for the PFD Inset Map, press the INSET Softkey). This step is not necessary on the
Weather Data Link (XM) Page.
2) Press the NEXRAD Softkey.
CompositedatafromalltheNEXRADradarsitesintheUnitedStatesisshown. Thisdataiscomposedof
themaximumreectivityfrom theindividualradarsweeps. Thedisplay oftheinformationis color-coded
toindicatetheweatherseveritylevel.AllweatherproductlegendscanbeviewedontheWeatherDataLink
(XM)Page.FortheNEXRADlegend (Figure6-11),pressthe LEGENDSoftkeywhenNEXRAD isselected
for display.
No Radar Coverage
Figure 6-11 NEXRAD Data with Legend
ThedisplayofnoradarcoverageisalwaysactivewheneitherNEXRADorEchoCoverageisselected.Areas
whereNEXRADradarcoverageandEchoTopsinformationisnotcurrentlyavailableorisnotbeingcollected
areindicatedinagrayshadeofpurple(Figure6-11).
ReFlectivity
Reectivityistheamountoftransmitted powerreturnedtotheradarreceiver. ColorsontheNEXRAD
displayaredirectly correlativeto thelevel ofdetectedreectivity. Reectivityas itrelatesto hazardous
weathercanbeverycomplex.
Theroleofradarisessentiallytodetectmoistureintheatmosphere.Simplyput,certaintypesofweather
reectradarbetterthan others.Theintensity ofaradar reectionisnotnecessarily anindicationofthe
weatherhazardlevel.Forinstance,wethailreturnsastrongradarreection,whiledryhaildoesnot.Both
wetanddryhailcanbeextremelyhazardous.
ThedifferentNEXRADechointensitiesaremeasuredindecibels(dB)relativetoreectivity(Z).NEXRAD
measures the radar reflectivity ratio, or the energy reflected
backto
theradar receiver(
designated by the
letterZ)
.ThevalueofZincreasesasthereturnedsignalstrengthincreases.