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Question 153-1 : In the icao standard atmosphere the decrease in temperature with height below 11 km is ? [ Learning aircraft ]
0.65°c per 100m
.2°c/1000 ft.
Question 153-2 : Which statement is correct regarding the icao standard atmosphere ?
At msl temperature is 15°c and pressure is 1013.25hpa
Question 153-3 : Qnh is defined as ?
Qfe reduced to msl using the values of the standard atmosphere.
.qnh doesn't give you msl mean sea level , zero height, just the pressure reading at which your altimeter will read zero..in cold air this will be above msl, in warm air below msl..at isa temperatures the qnh pressure level will be at msl, but will not necessarily be 1013 hpa.
Question 153-4 : Which of the following statements is true ?
Qnh can be equal to qfe.
Question 153-5 : Which statement is true ?
Qnh can be lower as well as higher than 1013.25 hpa.
Question 153-6 : When the subscale is set to the qnh of an airfield the pressure altimeter indicates ?
Elevation while landing.
.regardless of atmospheric conditions the altimeter will indicate field elevation at touchdown with qnh set because the qnh is the qfe reduced to sea level using isa conditions and the altimeter is calibrated to isa conditions.
Question 153-7 : The radiation of the sun heats ?
The surface of the earth, which heats the air in the troposphere.
Question 153-8 : The vertical extent of the friction layer depends primarily on ?
Stability, wind speed, roughness of surface.
.the height of the friction layer can vary depending on the type of terrain and wind speed. it depends also on the vertical temperature profile.if the air is stable environmental lapse rate less than 1.8°c/1000 ft any air moved up by turbulence will want to sink back to its original level in the atmosphere and there will be a relatively shallow friction layer...if the air is unstable elr more than 3°c/1000 ft then any movement up will continue up, increasing the depth of the friction layer.
Question 153-9 : The following temperatures have been observed over a station at 1200 utc station is at mean sea level.20000 ft 12°c.18000 ft 11°c.16000 ft 10°c.14000 ft 10°c.12000 ft 6°c.10000 ft 2°c.8000 ft +2°c.6000 ft +6°c.4000 ft +12°c.2000 ft +15°c.surface +15°c.which of the following statements is correct ?
Assuming that the msl pressure is 1013.25 hpa the true altitude of an aircraft would actually be higher than the indicated altitude.
.the isa temperature lapse rates is 2°c/1000 ft.at 2000 ft, temperature is +11°c..at 4000 ft, temperature is +7°c..at 6000 ft, temperature is +3°c..at 8000 ft, temperature is 1°c..at 10000 ft, temperature is 5°c..at 12000 ft, temperature is 9°c..at 14000 ft, temperature is 13°c..at 16000 ft, temperature is 17°c..at 18000 ft, temperature is 21°c..at 20000 ft, temperature is 25°c...apart from sea level, we can see from the observed temperatures that the air is warmer than isa throughout..an aircraft at fl180 for example will be at a higher true altitude than 18000 ft indicated altitude.
Question 153-10 : A significant inversion at low height is a characteristic of ?
Nocturnal radiation.
.air close to the surface is cooled significantly but the air above it isn't and the surface temperature falls below the temperature of the air above.
Question 153-11 : In order to reduce qfe to qnh, which of the following item s must be known ?
Elevation of the airfield.
Question 153-12 : The qnh is equal to the qfe if ?
The elevation = 0
Question 153-13 : Which of the following conditions gives the highest value of the qnh ?
Question 153-14 : The pressure altitude is equal to the true altitude if ?
Standard atmospheric conditions occur.
.pressure altitude is the altitude you read on an altimeter it's indicated altitude...true altitude depends on temperature. pressure altitude is only the same as true altitude in isa conditions.
Question 153-15 : You must make an emergency landing at sea. the qnh of a field on a nearby island with an elevation of 4000 ft is 1025 hpa and the temperature is 20°c..what is your pressure altimeter reading when landing if 1025 hpa is set in the subscale ?
Less than 0 ft.
.with temperature below isa, we are actually below the indicated altitude, but.with a subscale of 1025 hpa, while landing on the airport, 4000 ft would have been correct actual and indicated...if you fly lower than the indicated aiport altitude for which qnh has been calculated, correction will be reverse in that case , in colder air, our true actual altitude will be higher than altitude indicated on our altimeter...if you perform an emergency landing at sea, your altimeter will indicate 0 ft whereas you still are few meters above the sea.
Question 153-16 : The troposphere ?
Has a greater vertical extent above the equator than above the poles.
Question 153-17 : For a given airfield the qfe is 980 hpa and the qnh is 1000 hpa. the approximate elevation of the airfield is ?
160 metres.
.the qfe indicates, in standard atmosphere, the height of the aircraft above the official airport elevation an altimeter set to qfe will therefore read zero when on the ground. and you want to know the approximate elevation of the airfield... qfe 980 hpa = read zero on the altimeter..|..| m / 8m per hpa = 20 hpa 1000 980..|..| qnh 1000 hpa..8m x 20 hpa = 160 metres.
Question 153-18 : Which is true of the temperature at the tropopause ?
It is higher in polar regions than in equatorial regions
.polar tropopause 8km 45°c..tropicale tropopause 15 km 75°c..equatorial tropopause 16 km 80°c.. 491
Question 153-19 : Around paris on january 3rd at 1800 utc, the surface temperature, under shelter, is 3°c..the sky is covered by 8 oktas of stratus. qnh is 1033 hpa..if the sky is covered all night, the minimum temperature of the night of january 3rd to january 4th should be ?
Slightly below +3°c.
. the sky is covered by 8 oktas of stratus , it's overcast. the stratus cloud cover will act as a lid, close to the surface. the heat is kept close from the ground..there will still be a small temperature drop on a winter night, thus the minimum temperature should be slightly below +3°c.
Question 153-20 : On a clear sky, continental ground surface, wind calm, the minimum temperature is reached approximately ?
Half an hour after sunrise.
.the temperature falls continuously until a little after sunrise. the lowest temperature occurs at about sunrise plus 30 minutes.
Question 153-21 : An isohypse contour ?
Indicates the true altitude of a pressure level.
.isohypses contour lines are drawn on a constant pressure chart, therefore they indicate the true altitude of a pressure level.
Question 153-22 : Before landing, an altimeter set to qfe indicates ?
In standard atmosphere, the height of the aircraft above the official airport elevation.
.qfe is a 'q code' used by pilots and air traffic control to refer to the barometric altimeter setting which will cause an altimeter to read height above a particular runway threshold..an altimeter set to qfe will therefore read zero when on the ground at the beginning of the runway..this setting may be used during take off and landing and when flying in the circuit. a mnemonic for the code is 'q field elevation'.
Question 153-23 : In the mid latitudes the stratosphere extends on an average from ?
11 to 50 km.
Question 153-24 : An aircraft maintains a constant indicated altitude of 4500 ft from a 360 ft/amsl qnh 986 hpa to b 690 ft/amsl qnh 1011 hpa..assuming that the altimeter subscale setting remains unchanged at 986 hpa, the actual height of the aircraft above the surface at b will be ?
4485 ft.
The altimeter subscale setting remains unchanged at 986 hpa....difference at b 1011 986 = 25 hpa x 27 ft = 675 ft...4500 ft 690 ft = 3810 ft...actual height of the aircraft above the surface at b will be.3810 ft + 675 ft = 4485 ft... gargameleatpl.alt elevation = height, so correct answer is 3810 675= 3135.....you should take a break.....3135 ft is your corret answer, but if we provide an other answer and an explanation , it might be for a reason..when you will be over b, with a subscale setting of 986 hpa, you gonna turn the selection knob in a counterclockwise direction to set 1011 hpa, the indicated altitude will then increased by 25 hpa x 27 ft = 675 ft..4500 ft over b + 675 ft = 5175 ft..b elevation is 690 ft, thus actual height of the aircraft above the surface at b will be 5175 690 = 4485 ft.
Question 153-25 : An aircraft maintains a constant indicated altitude of 5500 ft from a 1050 ft/amsl qnh 968 hpa to b 650 ft/amsl qnh 1016 hpa..assuming that the altimeter subscale setting remains unchanged at 968 hpa, the actual height of the aircraft above the surface at b will be ?
6146 ft.
.the altimeter subscale setting remains unchanged at 968 hpa...difference at b 1016 968 = 48 hpa x 27 ft = 1296 ft..5500 ft 650 ft = 4850 ft..actual height of the aircraft above the surface at b will be.4850 ft + 1296 ft = 6146 ft.
Question 153-26 : An aircraft maintains a constant indicated altitude of 6500 ft from a 600 ft/amsl qnh 1012 hpa to b 930 ft/amsl qnh 977 hpa..assuming that the altimeter subscale setting remains unchanged at 1012 hpa, the actual height of the aircraft above the surface at b will be ?
4625 ft.
.the altimeter subscale setting remains unchanged at 1012 hpa...difference at b 977 1012 = 35 hpa x 27 ft = 945 ft..6500 ft 945 ft = 5570 ft..actual height of the aircraft above the surface at b will be.5570 ft 945 ft = 4625 ft.
Question 153-27 : An aircraft maintains a constant indicated altitude of 7500 ft from a 270 ft/amsl qnh 1021 hpa to b 1650 ft/amsl qnh 983 hpa..the altimeter sub scale setting remains unchanged at 1021 hpa, the actual height of the aircraft above the surface at b will be ?
4824 ft.
.the altimeter subscale setting remains unchanged at 1021 hpa...difference at b 983 1021 = 38 hpa x 27 ft = 1026 ft..7500 ft 1650 ft = 5850 ft..actual height of the aircraft above the surface at b will be.5850 ft 1026 ft = 4824 ft... dadoki.for better and logical understanding.you've got 1021hpa set on the altimeter. when you arrive at position b, you realize to change your altimeter height and set it to 983 hpa..to do it, of course, you turn anticlockwise the knob and height is decreasing on your altimeter altimeter went down about 1026 ft because you've just turned the knob anticlockwise downwards..so you get 6474 ft 7500 1026 and to adjust it to the elevation of the point b you subtract the elevation, so 6474 1650 = 4824ft... if you have a situation where point a has a lower qnh like 970 hpa and you will get at the point with higher qnh like 1020 hpa, so you are about to turn the knob clockwise or upwards to get the height, in this case the difference is 50 hpa and therefore 50 x 27 = 1350 ft, and then you just add this difference and again subtract the elevation of the point b, or present point.
Question 153-28 : Between mean sea level and a height of 20 km, the lowest temperature in the icao standard atmosphere isa is ?
56.5°c.
Question 153-29 : Considering the north atlantic area north of 60°n during winter, the mean height of the tropopause is approximately ?
29 000 ft.
.the tropopause is at the top of the troposphere. it marks the boundary between the troposphere and the next atmospheric layer, the stratosphere. the tropopause is defined as being that part of the atmosphere where temperature no longer decreases with height.. 491.29000 ft is approximately 9 km..the average height of the tropopause over the equator is 16 km, and 8 km over the poles. at 60°n, the mean height of the tropopause is approximately 29 000 ft.
Question 153-30 : Considering the north atlantic at latitude 50°n during winter, the mean height of the tropopause is approximately ?
31 000 ft.
.the tropopause is at the top of the troposphere. it marks the boundary between the troposphere and the next atmospheric layer, the stratosphere. the tropopause is defined as being that part of the atmosphere where temperature no longer decreases with height.. 491.31 000 ft is approximately 9.5 km..the average height of the tropopause over the equator is 16 km, and 8 km over the poles. at 50°n, the mean height of the tropopause is approximately 31 000 ft.
Question 153-31 : If the qfe, qnh and qff of an airport have the same value ?
The airport must be at msl.
.qfe, qnh and qff will all be at the same pressure for having the same value, and it can occur only if the airport is at msl..temperature or pressure can differ from isa at msl, there is no incidence.
Question 153-32 : In relation to the total weight of the atmosphere, the weight of the atmosphere between mean sea level and a height of 5500 m is ?
50%.
.50% of the atmosphere by mass is below an altitude of 5500 m..90% of the atmosphere by mass is below an altitude of 16 km..99.99997% of the atmosphere by mass is below 100 km.
Question 153-33 : The icao standard atmosphere isa assumes that temperature will reduce at the rate of ?
1,98°c per 1000 ft up to 36090 ft after which it remains constant to 65617 ft.
Question 153-34 : With all other quantities being constant, the density of the atmosphere increases with increasing ?
Air pressure.
.density depends on pressure and temperature..density is proportional to air pressure and inversely proportional to temperature.
Question 153-35 : You are flying over the sea at fl 250 and measure an outside temperature of 50°c. the pressure at sea level is 1023 hpa..what is your approximate true altitude calculated using normal vertical change in temperature with increase in height ?
23770 ft/amsl.
The following rules shall be considered for altimetry calculations.. the value for the barometric lapse rate near mean sea level is 27 ft 8 m per 1 hpa... to determine the true altitude/height the following rule of thumb, called the '4% rule', shall be used the altitude/height changes by 4% for each 10°c temperature deviation from isa....1023 1013 = 10 hpa...10 x 27 = 270 ft...25000 ft + 270 ft = 25270 ft....altitude/height changes by 4% for each 10°c temperature deviation from isa..temperature correction = 4 x 25.27 x 15.temperature correction is minus 1516.2 ft since air is colder than isa and we are looking for our true altitude our altimeter remains at fl250, setting 1013...our approximate true altitude 25270 1516 = 23754 ft..close enough to the result desired.
Question 153-36 : You are flying at fl 200..outside air temperature is 40°c, and the pressure at sea level is 1033 hpa.what is the true altitude ?
19310 ft.
.1033 1013 = 20 hpa x 27 ft = 540 ft...in isa conditions, altitude is 20540 ft, and oat will be.15°c 2°c x 20 = 25°c...oat is 40°c, to determine the true altitude/height the following rule of thumb, called the '4% rule', shall be used the altitude/height changes by 4% for each 10°c temperature deviation from isa...4% x 20.54 x 15 = 1232 ft...20540 1232 = 19308 ft.. minus 1232 ft because the air mass is colder than isa.
Question 153-37 : You are flying at fl 160..outside air temperature is 27°c, and the pressure at sea level is 1003 hpa..what is the true altitude ?
15100 ft.
.1013 1003 = 10 hpa x 27 ft = 270 ft...in isa conditions, altitude is 15730 ft, and oat will be.15°c 2°c x 16 = 17°c...oat is 27°c, to determine the true altitude/height the following rule of thumb, called the 4% rule , shall be used the altitude/height changes by 4% for each 10°c temperature deviation from isa...4% x 15.73 x 10 = 629 ft..15730 629 = 15101 ft.. minus 629 ft because the air mass is colder than isa.
Question 153-38 : Which statement concerning the tropopause is correct ?
The layer just above the tropopause is absolutely stable.
. 633.the layer just above the tropopause is absolutely stable from 12 km to 25 km, the temperature does not vary with height. it is an isothermal layer where we have absolute stability...note the icao standard atmosphere does not state that the tropopause has different heights around the earth tropopause is constant at 11 km for icao.
Question 153-39 : Pressure altitude is obtained by ?
Setting the altimeter to standard sea level pressure.
.1013.25 hpa is the isa mean sea level pressure also known as 'standard pressure setting'..in non isa conditions, the 1013.25 hpa pressure level will be above or below mean sea level. the standard pressure setting is used as an altimeter setting above the transition altitude.
Question 153-40 : What is, approximately, the temperature at 20000 ft in the icao standard atmosphere ?
25°c.
.the icao standard atmosphere isa assumes that temperature will reduce at the rate of 1,98°c per 1000 ft up to 36090 ft after which it remains constant to 65617 ft..the icao standard atmosphere isa also states 'at msl temperature is 15°c and pressure is 1013.25 hpa'...for calculation, we will assume a cooling rate of 2° per 1000 ft.15°c 20 x 2°c = 25°c.
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