Nielsen-Kellerman ClearNav Manual

A SERVICE OF

next previous

NKClearNavManual•Version0.5•July3,2008

Page67of86

4.2.3.5 AltitudeWindow

TheAltitudeWindowororisdisplayedinthelowerrightcorner

ofthescreen.ItcandisplayseveralaltitudenumbersandcanbeusedtoaccesstheSetMSLTab.

AltitudeDisplayOptions

• 

AltitudeMSL(MeanSeaLevel)

TheAltitudeMSListhealtitudethathasbeenadjustedtocompensateforchangesfromthe

standardatmosphere.YoucanandshouldedittheAltitudeMSLbeforetakeoffeverytimeyou

flybysettingittomatchtheknownairportelevation.Thisnumberistheoneusedforthefinal

glidecalculations–sobesuretosetitbeforetakeoff.TheAltitudeAGL(below)isbasedon

theMSLAltitudesoitwillonlydisplayaccuratelyiftheMSLAltitudeissetaccurately.Youcan

easilyusealocalautomatedweathertransmitter(AWOS)pressuresettingtoadjusttheMSL

Altitudeinflight.



• 

PressureAltitude

ThePressureAltitudeistherawaltitudefromthepressuretransducerandshowsthealtitudein

astandardatmosphere.Sincethelocalbarometricpressureisnotlikelytomatchthestandard

atmospherethisnumberwillbedifferentthantheMSLAltitude.Thisnumberisusedwhen

nearspecialuseairspacesuchaswhennear18,000feetintheUSA.



• 

AltitudeAGL(AboveGroundLevel)

TheAltitudeAGListheapproximatealtitudeabovegroundlevel.Thisisaverypowerfulfeature

becauseitmakesiteasytoknowyourapproximatealtitudeabovetheterrainataglance.You

willfindtheAltitudeAGLespeciallyusefulwhenflyinginmountainousareas.Ofcourse,the

elevationmodelisnotperfect,sodon’tcountonthisnumbertowarnyouaboutlocalobjects

thatstandupabovethegeneralterrainelevation.TheMSLAltitudeisusedtocalculatethe

AltitudeAGLsoitis

importanttosettheAltitudeMSLbeforetakeoff.TheAltitudeAGLis

calculatedbysubtractingthegroundelevation(fromthebuilt‐ingroundelevationmodel)from

theAltitudeMSL.

