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Figure6:PFDinnormallaw Figure7:PFDinalternate2law Figure8:Pitotprobediagram 1.6.9.6.3Consequencesofadropinthemeasuredtotalpressure ThefirstconsequenceofadropinmeasuredtotalpressureisadropintheMachandtheCAS.ThedropinMachleadstoadropinstandardaltitudeduetothecorrectionofthemeasuredstaticpressure.ThisdropisdifferentaccordingtotheADRunderconsideration:intheflightconditionsoftheevent,itisoftheorderof300to350ftfortheADR1and2andof80ftforADR3. ThedropinindicatedstandardaltitudealsocausesatransientvariationinVzbi.JustasthedropinstandardaltitudeislowerforADR3thanforADR1and2,thevariationinVzbiislowerforADR3thanforthetwoothers,asillustratedbythegraphbelow: Figure10:Effectofadropintotalmeasuredpressureonpressurealtitudeandverticalspeed ThedropinMachalsoimpactstheSATandthusthetrueairspeedandthewindspeed.Inthefollowingtable,thecaseanA330-200flyingatFL350atMach0.8in standardatmospherewitha30ktheadwindisgivenasanexampletoillustratetheconsequencesofPitoticingthatwouldresultinadropinMachfrom0.8to0.3. RealvalueIndicadedvalueMach0.80.3Standardaltitude(ft)35,000≈34,700CAS(kt)27297SAT(°C)-54-31TAS(kt)461182Windspeed(kt)-30249 Inaschematicmanner,thethresholdisstablebelowaMachoftheorderof0.3,thenreducesinaquasi-linearmannertoaMachoftheorder0.75,afterwhichitfallsmorerapidlywhentheMachincreasesuptoMach0.82: Figure11:EvolutionofstallwarningthresholdinrelationtoMach Adecreaseinspeedresultsinanincreaseintheangleofattack,iftheloadfactorisconstantandinacalmatmosphere.Inthiscase,thedecreaseinspeedcorrespondingtoanincreaseinagivenangleofattackdependsontheflightconditions: Flightcondition CruiseTakeoff/Approach Levelofdecreaseinindicatedspeedforanincreaseof1°intheangleofattack 25kt 5kt Thewindandtemperaturechartsshowthattheaverageeffectivewindalongtheroutecanbeestimatedatapproximatelytenknotstail-wind.OnthechartforFL340,thehighestairtemperatureislocatedaroundtheequator.Itisestimatedat-40°C,thatistosay,Standard+13°C.TheCATchartsdo