Garmin G1000 PDAs & Smartphones User Manual


 
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
381
HAZARD AVOIDANCE
6.8 TAWS-B
WARNING: Do not use TAWS information for primary terrain avoidance. TAWS is intended only to enhance
situational awareness.
NOTE: Terrain data is not displayed when the aircraft is outside of the installed terrain database coverage
area.
NOTE: The data contained in the TAWS databases comes from government agencies. Garmin accurately
processes and cross-validates the data but cannot guarantee the accuracy and completeness of the data.
TAWS-B(TerrainAwarenessandWarningSystem-ClassB)isusedtoincreasesituationalawarenessandaidin
reducingcontrolledightintoterrain(CFIT).TAWSprovidesvisualandauralannunciationswhenterrainand
obstaclesarewithinthegivenaltitudethresholdfromtheaircraft.Thedisplayedalertsandwarningsareadvisory
in nature only.
TAWS-BsatisesTSO-C151bClassBrequirementsforcertication.
TAWS-Brequiresthefollowingtooperateproperly:
•Avalidterrain/obstacle/airportterraindatabase
•Avalid3-DGPSpositionsolution
TAWS-Busesterrainandobstacleinformationsuppliedbygovernmentsources.Terraininformationisbased
onterrainelevationinformationinadatabasethatmaycontaininaccuracies.Individualobstructionsmaybe
shownifavailableinthedatabase.ThedataundergoesvericationbyGarmintoconrmaccuracyofthecontent,
perTSO-C151b.However,thedisplayedinformationshouldneverbeunderstoodasbeingall-inclusiveanddata
may be inaccurate.
TAWS-BusesinformationprovidedfromtheGPSreceivertoprovideahorizontalpositionandaltitude.GPS
altitudeisderivedfromsatellitemeasurements.GPSaltitudeisthenconvertedtotheheightabovegeodetic sea
level(GSL),whichistheheightabovemeansealevel(MSL)calculatedgeometrically.GSLaltitudeisusedto
determineTAWS-Balerts.GSLaltitudeaccuracyisaffectedbysatellitegeometry,butisnotsubjecttovariations
inpressureandtemperaturethatnormallyaffectpressurealtitudesensors.GSLaltitudedoesnotrequirelocal
altimetersettingstodetermineMSLaltitude.Itisawidely-usedMSLaltitudesource.Therefore,GSLaltitude
providesahighlyaccurateandreliableMSLaltitudesourcetocalculateterrainandobstaclealerts.
TheterrainandobstacledatabasesusedbyTAWS-BarereferencedtoMSL.UsingtheGPSpositionandGSL
altitude,TAWS-Bdisplaysa2-Dpictureof thesurroundingterrain andobstaclesrelativetothepositionand
altitudeoftheaircraft.Furthermore,theGPSpositionandGSLaltitudeareusedtocalculateand“predict”the
aircraft’sightpathinrelationtothesurroundingterrainandobstacles.Inthismanner,TAWS-Bcanprovide
advanced alerts of predicted dangerous terrain conditions.
Baro-correctedaltitude(orindicatedaltitude)isderivedbyadjustingthealtimetersettingforlocalatmospheric
conditions. The most accuratebaro-corrected altitudecanbeachievedbyfrequently updating the altimeter
setting to the nearest reporting station along the flight path. However, because actual atmospheric conditions
seldommatchthestandardconditionsdenedbytheInternationalStandardAtmosphere(ISA)model(where