Chapter 2 section 4 flight instrument

FlightInstruments•Mostaircraftareequippedwithastandardsetofflightinstrumentswhichgivethepilotinformationabouttheaircraft'sattitude,airspeed,andaltitude.Mostaircrafthavethesesixbasicflightinstruments:•Altimeter(高度表)•Attitudeindicator（姿态指示仪）•Airspeedindicator（空速表）•Headingindicator（航向指示器）•Turnandbankindicator（转弯倾斜指示器）•Verticalspeedindicator（垂直速度指示器）1.Altimeter(高度表)Analtimeterisaninstrumentusedtomeasurethealtitudeofanobjectaboveafixedlevel.Givestheaircraft'sheight(usuallyinfeetormeters)abovesomereferencelevel(usuallysea-level)bymeasuringthelocalairpressure.Itisadjustableforlocalbarometricpressure(气压)(referencedtosealevel)whichmustbesetcorrectlytoobtainaccuratealtitudereadings.•Mostaltimetersconsistofadialcalibratedfrom‘0’to‘9’andthreedifferentsized‘needles’or‘hands’.•Thelongesthandreadshundredsoffeetfromthegraduateddial.•Themediumhandreadsthousandsoffeetfromthegraduateddial.•Theshortesthandreadstensofthousandsoffeetfromthegraduateddial.Thealtimeterimageindicatesanaltitudeof1400feetwiththebaro-scalesetat29.9in/Hg–equivalentto1013hPa.(standardatmosphericpressure)Notice:in/Hg(英寸汞柱InchesofMercury)=33.86hPa(hectopascals百帕)•Apressure-settingknobislocatedontheinstrumentforsettingatmosphericpressureatsealevel(knownas‘QNH’修正海压)•Whenthepressure-settingknobisturnedclockwise,thepressureshownonthepressuresettingsubscaleincreasesand,atthesametime,thereadingonthealtimeterincreases---viceversa,whentheknobisturnedanti-clockwise.–Incorrectsubscalesettingswillgiveincorrectaltitudeindications.Forexample,ifthesettingistoohigh,thealtimeterwillindicateahigheraltitudethanactualwhichspellsDANGER.Ifthesubscalesettingistoolow,thealtimeterwillreadlowerthantheairplane'sactualaltitude.2.Attitudeindicator（姿态指示仪）Showstheaircraft‘sattituderelativetothehorizon.Fromthisthepilotcantellwhetherthewingsarelevelandiftheaircraftnoseispointingaboveorbelowthehorizon.Thisisaprimaryinstrumentforinstrumentflightandisalsousefulinconditionsofpoorvisibility（低能见度）.Theattitudeindicatoristheonlyinstrumentthatgivesdirectinformationaboutanaircraft'sattitude.climbingandturningtotheright•Theminiatureairplane'srelativepositiontothehorizonindicatesitsattitude:nosehigh,noselow,leftbank,rightbank.3.Airspeedindicator（空速表）Theairspeedindicator,alsoknownastheASI,measures‘indicated’airspeed（表速、指示空速）whichisusedasameasureofspeedoftheairplanethroughtheair.Itshowstheaircraft‘sspeed(usuallyinknots节)relativetothesurroundingair.Itworksbymeasuringtheram-air(冲压空气)pressureintheaircraft’spitottube（空速管).Theindicatedairspeedmustbecorrectedforairdensity(whichvarieswithaltitude,temperatureandhumidity)inordertoobtainthetrueairspeed（真空速）,andforwindconditionsinordertoobtainthespeedovertheground（groundspeed）.Theairspeedindicatorinthecockpitisalsocoveredincolor-codedmarkingsthatprovidethepilotwithimportantinformationtooperatetheplanesafely.Thesemarkingsdenoteregionswheretheplanecanbesafelyoperatedandlimitsthatshouldnotbeexceeded.•FlapOperatingRange-Thewhitearcspecifiesthespeedrangeoverwhichthewingflapscanbeextended.•Power-OffStallSpeedwithFlapsExtendedandLandingGearDeployed(VS0)-Thelowerlimitofthewhitearcdenotestheminimumspeedatwhichtheplanecanbeflowninlandingconfigurationwithoutstalling.Oncestalled,thewingrapidlylosesliftandtheaircraftbecomesdifficultorimpossibleforthepilottocontrol.•MaximumFlapsExtendedSpeed(VFE)-Theupperlimitofthewhitearcdictatesthemaximumairspeedatwhichtheflapscanbefullyextended.Higherspeedswillinduceloadsontheflapsthatmayexceedtheirstructurallimitsresultingindamagetotheaircraft.•NormalOperatingRange-Thegreenarcspecifiestherangeofairspeedsoverwhichtheplanecanbesafelyflownincruiseconfigurationwithflapsandlandinggearretracted.•Power-OffStallSpeedwithFlapsandLandingGearRetracted(VS1)-Thelowerlimitofthegreenarcdenotestheminimumspeedatwhichtheplanecanbeflownincruiseconfigurationwithoutstalling.•MaximumNormalOperationSpeed(VNO)-Theupperlimitofthegreenarcdictatesthemaximumcruisespeedinacleanconfiguration.•CautionRange-Theyellowarcspecifiesaspeedrangethepilotshouldavoidunlessflyinginverysmoothair.•NeverExceedSpeed(VNE)-Theredlinedictatesthemaximumspeedatwhichtheplanecanbeoperatedinsmoothair.Thepilotshouldneverflyfasterthanthisairspeedorriskstructuraldamage.AirspeedandGroundspeed•Threetypesofairspeed–Indicatedairspeed（表速、指示空速）–Calibratedairspeed（修正空速）–Trueairspeed（真空速）•Groundspeed（地速）•Indicatedairspeed（表速、指示空速）–Theairspeedindicatedonairspeedindicator(ASI)incockpitisindicatedairspeed.–Indicatedairspeedislinkedtodynamicpressure.–Question?Asthealtitudeincreases,iftheindicatedairspeedisconstant,istheindicatedspeedshowninASIequaltotherealspeedofairplane?•Calibratedairspeed（修正空速）–Itisindicatedairspeedcorrectedforminorerrorsthatoccurwithintheinstrument(instrumenterror)andinsensingthepressuresthatareusedtomeasuretheairspeedwithinairspeedindicator(positionorpressureerror).–Althoughmanufacturersattempttokeepairspeederrorstoaminimum,itisnotpossibletoeliminateallerrorsthroughouttheairspeedoperatingrange.–Thiserrorisgenerallygreatestatlowairspeeds.Inthecruisingandhigherairspeedranges,indicatedai