Below the tropopause when descending at a constant CAS ?
Regulation > weather
Source: Telepilote theorique examen 41
Below the tropopause in standard conditions when descending at a constant Mach number ?
Calibrated Air Speed CAS is ?
Concerning airspeed indicator ias The indicated reading on instrument. an airspeed indicator displays ias. 
Considering relationship between cas and eas Eas always lower than or equal to cas. eas cas corrected compressibility compressibility error always results in an incorrect a higher ias/cas being observed on airspeed indicator. 
Due to its conception altimeter measures a Eas always lower than or equal to cas. eas cas corrected compressibility compressibility error always results in an incorrect a higher ias/cas being observed on airspeed indicator. 
During descent total pressure probe of airspeed indicator becomes blocked in this case 1 ias becomes greater than cas2 ias becomes lower than cas3 maintaining ias constant vmo may be exceeded4 maintaining ias constant aircraft may stallthe combination regrouping all correct statements Eas always lower than or equal to cas. joangoris the only way to maintain a constant ias with a blocked pitot tube maintaining your altitude nothing to do with your throttle or tas no matter if you are near stall or near overspeed so i don't understand last two statements please help? thanks total pressure probe = pitot tube when it becomes blocked total pressure in capsule fixed (dynamic pressure + static) during descent static pressure from static port will increase compresses capsule causing indicated airspeed (ias) to decrease (your airspeed indicator becomes an altimeter!) when you read 'maintaining ias constant vmo may be exceede you must understand that you are in cockpit your speed decreasing so your action will be to accelerate your vmo may be exceeded. Question 41-8
For same tas when pressure altitude decreases below tropopause Mach number decreases. Pressure altitude decreases = descending for those questions use very simple 'ertm' diagram the tas line vertical because question states for same tas ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-9
For same tas when pressure altitude increases below tropopause Mach number increases. Pressure altitude increases = climbing for those questions use very simple 'ertm' diagram the tas line vertical because question states for same tas ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-10
Given pt = total pressureps = static pressurepd = dynamic pressure Mach number increases. Pressure altitude increases = climbing for those questions use very simple 'ertm' diagram the tas line vertical because question states for same tas ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-11
Given pt = total pressureps = static pressurepso = static pressure at sea level calibrated airspeed cas a function of Mach number increases. Pressure altitude increases = climbing for those questions use very simple 'ertm' diagram the tas line vertical because question states for same tas ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-12
Given pt = total pressureps = static pressurepso = static pressure at sea leveldynamic pressure Mach number increases. Pressure altitude increases = climbing for those questions use very simple 'ertm' diagram the tas line vertical because question states for same tas ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-13
Given pt total pressureps static pressurepd dynamic pressurethe airspeed indicator fed Mach number increases. the asi a sensitive differential pressure gauge which measures promptly indicates difference between pitot (total pressure) static pressure (total pressure static pressure = dynamic pressure) these two pressures are equal when aircraft parked on ground in calm air when aircraft moves through air pressure on pitot line becomes greater than pressure in static lines this difference in pressure registered the airspeed pointer on face of instrument the airspeed indicator fed with pt ps it works on pt ps = pd. Question 41-14
If an aircraft maintaining a constant cas and flight level flying from a cold air mass into warmer air Mach number increases. flying from a cold air mass into warmer air = density decreases (with higher temperature air expanding density reduced) cas = 1/2 x density x tas² cas constant density decreases then tas must increase mach = tas / local speed of sound local speed of sound varies only with temperature (lss varies with square root of absolute temperature formula lss = 39 x square root of (oat+273)) the question states 'flying from a cold air mass into warmer air' thus if tas increases lss increases mach number remains constant. Question 41-15
If an aircraft maintaining a constant cas and flight level flying from a warm air mass into colder air Mach number increases. flying from a warm air mass into colder air = density increases (with lower temperature air contracting density inscreased) situation similar to descent with a constant cas for those questions use very simple 'ertm' diagram the cas line vertical because question states maintaining a constant cas ertm e as/r as(rectified air speed or cas)/t as/m ach but mach number will not decrease since mach number lss (local speed of sound) are proportional to each other which means that temperature decrease will cause a decrease in lss as well as tas as tas reduces at same rate mach number will remain constant. Question 41-16
If oat decreases when at a constant mach number Mach number increases. relation between mach number tas depends only on oat is independant of static pressure at a constant flight level constant mach number if oat decreases tas will decrease but it would also do it in a climb in standard atmosphere descent in an inversion mach number = tas /lss local speed of sound (lss) changes in proportion to temperature if temperature reduce lss reduce thus tas must reduce to keep mach number constant. Question 41-17
If oat decreases when at a constant tas Mach number increases. relation between mach number tas depends only on oat is independant of static pressure at a constant flight level constant tas if oat decreases mach number will increase but it would also do it in a climb in standard atmosphere descent in an inversion mach number = tas / lss local speed of sound (lss) changes in proportion to temperature if temperature reduce lss reduce thus mach number must increase to keep tas constant. Question 41-18
If oat increases when at a constant mach number Mach number increases. Relation between mach number tas depends only on oat is independant of static pressure at a constant flight level constant mach number if oat increases tas will increase but it would also do it in a climb in standard atmosphere descent in an inversion mach number = tas / lss local speed of sound (lss) changes in proportion to temperature if temperature increase lss increase thus tas must increase to keep mach number constant you can also say an oat increasing similar to a decrease in altitude use 'ertm' diagram the mach line vertical because question states at a constant mach number ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-19
If oat increases when at a constant tas Mach number decreases. Relation between mach number tas depends only on oat is independant of static pressure at a constant flight level constant tas if oat increases mach number will decrease but it would also do it in a climb in standard atmosphere descent in an inversion mach number = tas / lss local speed of sound (lss) changes in proportion to temperature if temperature increase lss increase thus mach number must reduce to keep tas constant. Question 41-20
During a climb at a constant calibrated airspeed cas below tropopause in standard conditions Tas mach number increase. For those questions use very simple 'ertm' diagram the cas line vertical because question states climb at a constant calibrated airspeed (cas) ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-21
In standard atmosphere when descending at constant cas Tas mach number increase. For those questions use very simple 'ertm' diagram the cas line vertical because question states descending at constant cas ertm e as/r as(rectified air speed or cas)/t as/m ach cas = 1/2 rho v² density will increase during descent in order to maintain constant cas only v (tas) can be reduced. Question 41-22
In absence of position and instrument errors cas equal to Tas mach number increase. an airspeed indicator displays ias the error in altimeter readings caused the variation of static pressure near source known as position error instrument error refers to combined accuracy precision of a measuring instrument or difference between actual value the value indicated cas ias corrected position instrument errors. Question 41-23
In absence of position and instrument errors Tas mach number increase. an airspeed indicator displays ias the error in altimeter readings caused the variation of static pressure near source known as position error instrument error refers to combined accuracy precision of a measuring instrument or difference between actual value the value indicated cas ias corrected position instrument errors. Question 41-24
The compressibility correction to cas to give eas 1 may be positive 2 always negative3 depends on mach number only 4 depends on pressure altitude only the combination regrouping all correct statements Tas mach number increase. equivalent air speed (eas) obtained from calibrated air speed (cas) correcting compressibility error the size of compressibility error varies with mach number is always negative air speed indicator are calibrated standard atmosphere pressure temperature density thus reading dependent on dynamic pressure 1/2 x rho x v² (the error in readings due to compression of air on forward part of pitot tube component moving at high speeds) to avoid this error a compressibility correction has to be applied compressibility correction = (1 + (1/4 x m²) eas = dynamic pressure x (1 + (1/4 x m²)) the compressibility factor always negative is directly dependent on mach number. Question 41-25
True air speed tas obtained from indicated air speed ias correcting the following errors 1 instrument 2 position 3 compressibility 4 density the combination regrouping all correct statements Tas mach number increase. equivalent air speed (eas) obtained from calibrated air speed (cas) correcting compressibility error the size of compressibility error varies with mach number is always negative air speed indicator are calibrated standard atmosphere pressure temperature density thus reading dependent on dynamic pressure 1/2 x rho x v² (the error in readings due to compression of air on forward part of pitot tube component moving at high speeds) to avoid this error a compressibility correction has to be applied compressibility correction = (1 + (1/4 x m²) eas = dynamic pressure x (1 + (1/4 x m²)) the compressibility factor always negative is directly dependent on mach number. Question 41-26
Tas Eas corrected density error. true air speed (tas) is ias corrected instrument position compressibility density errors cas corrected compressibility density errors eas corrected density error. Question 41-27
When climbing at a constant cas in a standard atmosphere 1 tas decreases 2 tas increases 3 mach number increases 4 mach number decreases the combination regrouping all correct statements Eas corrected density error. true air speed (tas) is ias corrected instrument position compressibility density errors cas corrected compressibility density errors eas corrected density error. Question 41-28
When climbing at a constant cas Mach number increases. For those questions use very simple 'ertm' diagram the cas line vertical because question states climbing at a constant cas ertm e as/r as(rectified air speed or cas)/t as/m ach cas = 1/2 rho v² density will decrease during climb in order to maintain constant cas only v (tas) can be increased mach = tas / local speed of sound local speed of sound varies only with temperature temperature decreases during climb thus if tas increases lss decreases mach number increases. Question 41-29
When descending at a constant cas in a standard atmosphere 1 tas increases 2 tas decreases 3 mach number increases 4 mach number decreases the combination regrouping all correct statements Mach number increases. For those questions use very simple 'ertm' diagram the cas line vertical because question states climbing at a constant cas ertm e as/r as(rectified air speed or cas)/t as/m ach cas = 1/2 rho v² density will decrease during climb in order to maintain constant cas only v (tas) can be increased mach = tas / local speed of sound local speed of sound varies only with temperature temperature decreases during climb thus if tas increases lss decreases mach number increases. Question 41-30
When descending at a constant cas Mach number decreases. for those questions use very simple 'ertm' diagram the cas line vertical because question states descending at a constant cas ertm e as/r as(rectified air speed or cas)/t as/m ach cas = 1/2 rho v² density will increase during descent in order to maintain constant cas only v (tas) can be reduced mach = tas / local speed of sound local speed of sound varies only with temperature temperature increases during descent thus if tas decreases lss increases mach number decreases. Question 41-31
When descending at a constant mach number Mach number decreases. For those questions use very simple 'ertm' diagram the mach line vertical because question states descending at a constant mach number ertm e as/r as(rectified air speed or cas)/t as/m ach. Question 41-32
When flying in cold air colder than standard atmosphere indicated altitude Higher than true altitude. in standard atmosphere temperature conditions your indicated altitude will be same as your true altitude but if it warmer than isa your true altitude will be higher than your indicated altitude if it colder than isa your true altitude will be lower than your indicated altitude. Question 41-33
When flying in cold air colder than standard atmosphere altimeter will Higher than true altitude. in standard atmosphere temperature conditions your indicated altitude will be same as your true altitude but if it warmer than isa your true altitude will be higher than your indicated altitude if it colder than isa your true altitude will be lower than your indicated altitude therefore your altimeter will overestimate in cold air. Question 41-34
When flying in warm air warmer than standard atmosphere indicated altitude Lower than true altitude. in standard atmosphere temperature conditions your indicated altitude will be same as your true altitude but if it warmer than isa your true altitude will be higher than your indicated altitude if it colder than isa your true altitude will be lower than your indicated altitude therefore your altimeter will overestimate in cold air. Question 41-35
Which of following statements are correct an aeroplane cruising at fl 60 with a true airspeed tas of 100 kt in standard atmospheric conditions 1 the tas approximately 10% higher than ias 2 the difference between equivalent airspeed eas and calibrated airspeed cas negligible 3 the speed displayed on airspeed indicator a calibrated airspeed cas if position error and instrument error are zero 2 3 are all correct. tas = ias + 2% per 1000 ft altitude eas cas corrected compressibility at low speed low altitude compressibility negligeable cas ias corrected position instrument errors. Question 41-36
With eas and density altitude we can deduce 2 3 are all correct. with eas density altitude we can deduce tas with eas pressure altitude (zp) we can deduce cas. Question 41-37
With eas and pressure altitude zp we can deduce 2 3 are all correct. eas cas corrected compressibility error which you would work out from pressure altitude with eas density altitude we can deduce tas. Question 41-38
During a climb total pressure probe of airspeed indicator becomes blocked if pilot maintains a constant indicated airspeed true airspeed Decreases until reaching stall speed. if static system remains clear airspeed indicator acts as an altimeter true air speed (tas) ias corrected instrument position compressibility density errors thus with total pressure probe blocked to maintain a constant ias while altitude increases you must pull stick (or control column) if not indicated speed will increase you will quickly reach stalling speed. Question 41-39
With constant weight and configuration an aircraft always takes off at same Decreases until reaching stall speed. pressure errors (i e errors in measurement of pitot static pressure) are specific to aircraft so we have to allow them instrument error specific to instrument so we have to get instrument calibrated take it into account having corrected indicated airspeed these two errors we have calibrated airspeed however small at take off speed we should correct the effect of compressibility that will give us equivalent airspeed for a given weight configuration take off speed will depend on density of air so we don't correct that hence aircraft will take off at same eas. Question 41-40
An airspeed indicator includes a capsule inside this capsule Total pressure outside static pressure. the asi a sensitive differential pressure gauge which measures promptly indicates difference between pitot (total pressure) static pressure (total pressure static pressure = dynamic pressure) these two pressures are equal when aircraft parked on ground in calm air when aircraft moves through air pressure on pitot line becomes greater than pressure in static lines this difference in pressure registered the airspeed pointer on face of instrument.
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