Pilot's Guide

Garmin G1000 Pilot’s Guide for the Hawker Beechcraft C90A/GT/GTi
190-00663-02 Rev. B338
HAZARD AVOIDANCE
hail
Hail results from updrafts carrying water high enough to freeze.  Therefore, the higher the top of a
thunderstorm, the greater the probability that it contains hail. Vertically scanning the target return can
givetheradartopofathunderstormthatcontainshail.Radartopisthetopofastormcellasdetectedby
radar.Itisnottheactualtop,ortruetopofthestorm.Theactualtopofastormcellisseenwiththeeyes
inclearairandmaybemuchhigherthantheradartop.Theactualtopdoesnotindicatethetopofthe
hazardous area.
Hailcanfallbelowtheminimumreectivitythresholdforradardetection.Itcanhavealmofwateron
itssurface,makingitsreectivecharacteristicssimilartoaverylargewaterdroplet.Becauseofthislmof
water, and because hail stones usually are larger than water droplets, thunderstorms with large amounts
ofwethailreturnstrongersignalsthanthosewithrain.Somehailshaftsareextremelynarrow(100yards
orless)andmakepoorradartargets.Intheupperregionsofacellwhereiceparticlesaredry(noliquid
coating),targetreturnsarelessintense.
Hailshaftsareassociatedwiththesameradartargetreturncharacteristicsastornados.U-shapedcloud
edgesthreetosevenmilesacrosscanalsoindicatehail.Thesetargetreturnsappearquitesuddenlyalong
anyedgeofthecelloutline.Theyalsochangeinintensityandshapeinamatterofseconds,makingvigilant
monitoring essential.
OPERATION IN WEATHER MODE
WARNING: Begin transmitting only when it is safe to do so. When transmitting while the aircraft is on the
ground, no personnel or objects should be within 11 feet of the antenna.
CAUTION: In Standby mode, the antenna is parked at the center line. It is always a good idea to put the
radar in Standby mode before taxiing the aircraft to prevent the antenna from bouncing on the bottom stop
and possibly causing damage to the radar assembly.
WhentheweatherradarsystemisintheWeatherorGroundMapmode,thesystemautomaticallyswitches
toStandbymodeonlanding.
In Reversionary mode, the weather radar system automatically switches to Standby mode. The system
remainsinStandbymodeuntilbothdisplaysarerestored.InReversionarymode,theweatherradarsystem
cannot be controlled.