The atmosphere is composed, in order from least to greatest, of
carbon dioxide, oxygen and nitrogen.
Water vapour is found in which layer of Earth's atmosphere?
Troposphere
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The atmosphere is composed, in order from least to greatest, of
carbon dioxide, oxygen and nitrogen.
Water vapour is found in which layer of Earth's atmosphere?
Troposphere
The atmospheric layers in order from the most dense to the least dense are
Troposphere, Stratosphere, Mesosphere, and Thermosphere.
With an elevation of 500 feet ASL and a surface temperature of 15°C. The expected temperature at 6 500 feet ASL would be
6 500 ft - 500 ft = 6 000 ft altitude change
6 x 1.98°C = 11.88°C
15°C - 11.88°C = 3.12°C
The correct answer is: 3°C.
What defines the start of the Tropopause?
Sudden change in lapse rate.
The air temperature in the Stratosphere does what with altitude
increases with altitude
The uniform temperature throughout the Stratosphere is
FALSE → temp in stratosphere is not uniform, it increases
Most weather is prevented from rising through the atmospheric layers by the
Tropopause
The Mesosphere is characterized by
very low temperatures.
The Thermosphere is characterized by
very high temperatures.
What percentage of Earth's atmosphere is composed of water vapour?
Less than 1 %
The expected temperature at 3 000 feet ASL in standard atmospheric conditions would be
15°C at sea level - (1.98°C / 1 000 ft x 3 000 ft) = 9.06°C
The correct answer is: 9°C.
Barometric altimeters are calibrated to react to temperature variations according to
standard atmospheric conditions
In the Northern Hemisphere the height of the Tropopause
decreases from Equator to the north Pole.
In the Northern Hemisphere the height of the Tropopause
decreases from Equator to the north Pole.
The ozone layer is located in the
stratosphere
The layer that most of the atmospheric humidity is concentrated in is the
Troposphere.
While at FL140 the OAT is -12°C. Under standard atmospheric conditions the expected temperature at FL110 would be
Standard temp at 11 000 feet
11 x 1.98 = 21.78
15 - 21.78 = -6.78 (-7)
The correct answer is: -7°C.
The boundary layer between Troposphere and the Stratosphere is known as the
Tropopause.
The correct composition of the atmosphere by volume is
21% oxygen and 78% nitrogen.
The thickness of the Troposphere varies with
Parallels of Latitude.
The ICAO standard atmosphere temperature at 9,500 feet is closest to
-4 dec C
The percentage concentration of gases in the atmosphere is constant from the surface to altitude with the exception of
water vapour.
Concerning the conditions in the lower part of the atmosphere it is correct that it is lower
the Tropopause is lower during the winter than in summer.
During cruise at FL200 the OAT is -35°C. The air mass therefore has an average temperature which is
Standard temperature is 15°C at sea level.
Therefore with a lapse rate of approx 2°C /1 000 feet
20 x 2° = 40°
15° - 40° = -25°
Standard temp at FL200 would be -25°
The correct answer is: 10°C colder than ISA.
The troposphere vertical extent is greater where
has a greater vertical extent above the Equator than above the Poles.
The pressure in the Stratosphere decreases with ______
decreases with height.
The feature that is associated with the Tropopause is
the abrupt change of lapse rate.
The Tropopause sits at approximately . . . . . feet over the Equator and at . . . . . feet over the Poles.
54 000, 25 000
29.92 in Hg is equivalent to how many millibars of pressure?
1013.25 millibars
According to standard atmosphere the station pressure as measured by two stations in the same region but at different altitudes will be
Air gets thinner as altitude increases. So a station at a lower altitude than another will have a higher pressure given matching conditions. This is the case in this question by stating that standard conditions apply, so the station that is higher is in thinner air so lower pressure and higher pressure at the lower station.
The correct answer is: higher as measured by the lower station.
In a high pressure system, the general movement of air may be explained as ______ and _______
diverging and descending.
According to the properties of standard atmosphere a station registering 28.00 in Hg at 2 000 feet elevation would report an altimeter setting of
30.00 in Hg.
1 in Hg = 1 000 feet
2 000 / 1 000 = 2 in Hg
28 + 2 = 30 in Hg
The correct answer is: 30.00 in Hg.
Anticyclonic pressure systems in the Northern hemisphere represent
sinking air that is rotating clockwise and flowing outward from the center.
Cyclonic pressure systems in the Southern Hemisphere represent
rising air that is rotating clockwise and flowing inwards towards the center
Which weather map symbol represents a high pressure ridge?
crisscross pattern /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\
Precipitation is more readily associated with which weather system? (cyclonic or anticyclonic)
cyclonic
Lines joining areas of equal pressure are called . . . . . and are separated by . . . . . millibars.
isobars, 4
The indicated altitude is 8 500 feet with an altimeter setting of 29.42 in Hg. The pressure altitude would be
Select one:
a.8 000 feet.
b.8 500 feet.
c.9 000 feet.
d. 8 450 feet.
29.92 in Hg - 29.42 in Hg = 0.5 x 1 000 = 500 feet + 8 500 feet = 9 000 feet
The altimeter compares the difference between actual atmospheric pressure and the pre-selected pressure value in the Kollsman window (in this case 29.42) and converts this difference into an altitude. 29.42 is closer to the atmospheric pressure flying in 8 500 feet than 29.92, therefore a lower altitude than the Pressure Altitude is being indicated.
The correct answer is: 9 000 feet.
Aircraft performance is best predicated by the
Select one:
Density altitude
Altimeters that are in error by more than . . . . . feet when given a correct altimeter setting must be re-calibrated.
50 ft
After a cold front has moved in the colder air causes the air pressure to increase resulting in a slightly higher altimeter setting. T/F
True, altitude corrections should be made to obstacle clearance altitudes when temperature is 0°C or below.
The conditions that would be the safest to ensure that a flight level clears all the obstacles by the greatest margin would be a
If you go from high to low look out below. Altimeter is set too high the aircraft will be lower than indicated.
But in this question it is stating the reverse in the answer. Low to high. So the aircraft will be higher than indicated. If the altimeter setting was 28.72 (29.92 used in the question) and the area flown into had a higher setting, than as you reset the altimeter it would increase showing the aircraft is flying too high (better obstacle clearance).
The correct answer is: temperature more than or equal to ISA and an altimeter setting greater than 29.92 in Hg.
An aircraft is flying at FL180 in the Northern Hemisphere with a crosswind from the left. It is correct concerning true altitude that
Select one:
a without knowing temperatures at FL180 this question cannot be answered.
b. it decreases.
c. it remains constant.
d. it increases.
True altitude is the actual height above sea level. This altitude changes based on changes in temperature and or pressure. In this question the pressure is changing. Because the crosswind is from the left the aircraft is approaching a low pressure system. As the pressure decreases (no change to the altimeter setting is made) the indicated altitude would increase if the true altitude is maintained. If indicated altitude is maintained then the true altitude would decrease.
IT DECREASES
Which condition would cause the altimeter to indicate a lower altitude than that actually flown?
Air temperature higher than standard.
Decreasing air pressure
Increasing air pressure
Decreasing temperature
Increasing temperature
The factors that increase density altitude for a given aerodrome are:
Decreasing air pressure and increasing temperature
Flying over mountains with a temperature of 24ºC and the altimeter setting of 30.22 in Hg received from a nearby airfield. The terrain below the aircraft rises to 4 000 feet ASL, the true altitude when reaching 6 000 feet ASL will be
Pressure Altitude = 5 700 feet (29.92 - 30.22 = - 0.3 x 1 000 = - 300 + 6 000 feet =)
Temperature is 24ºC
Using the E6B correct altitude of 2 000 feet AGL (= IALT 6 000 - Elev 4 000), will get 2 145 feet and add to 4 000 feet ASL
Air temperature has influence on true altitude depending on height of column of air above the ground level
The solution is 6 145 feet
Math version.
The aircraft is 2 000 feet above the terrain (indicated altitude 6 000 feet - terrain 4 000 feet)
2 x 4 (feet/1 000) = 8
8 x +21 (degrees above standard) = 168
2 000 + 168 = 2 168 feet AGL + 4 000 feet elev = true altitude of 6 168 feet ASL
Do not correct the elevation for non-standard conditions.
The correct answer is: 6 145 feet.
An aircraft takes off from Doha, field elevation 30 feet ASL, with the altimeter setting of 30.12 in Hg set on the altimeter. The aircraft then lands at Al Ain, field elevation 500 feet ASL, but without re-setting the altimeter sub-scale. If the altimeter setting at Al Ain at the time of landing is 29.98 in Hg the aircraft's altimeter read on touch-down
The difference between 30.12 in Hg and 29.98 in Hg results in a 140 feet difference.
Since the reference is still set to the higher air pressure, lower altitude, this difference needs to be added to the elevation.
The correct answer is: 640 feet.
Flying at FL220 in an air mass which is 15°C colder than ISA with the local altimeter setting of 29.02 in Hg. What would be the true height over terrain that is at 7 000 feet?
Because it is stated as FL220 that means a pressure altitude of 22 000 feet. Altimeter is set to 29.92 in Hg.
Find what the altimeter would indicate when set to 29.02 in Hg. Because it is lower when you mechanically turn the setting down the altitude decreases. in this case 900 feet.
29.92 - 29.02 = 0.9 x 1 000 = 900 feet
Because the Pressure Level 29.02 is at a higher altitude than the Pressure Level 29.92, we have to subtract the 900 feet from PA to get Indicated Altitude (turning subscale down).
22 000 - 900 = 21 100 feet
The altimeter set to the current altimeter setting would indicate 21 100 feet.
To find out standard temperature at 22 000 feet calculate
15°C - (22 x 2°C) = -29°C
Actual outside temperature is 15°C colder than standard, therefore -29 - 15 = -44°C
Refer to E6B given: PA 22 000 feet; Temp -44°C;
Find 14 100 feet (= 21 100 - 7 000 = indicated/calibrated altitude AGL, this represents the "column of air" above elevation) on inner scale.
Read True height AGL on outer scale = 13 200 feet
If were asked 13 200 + 7 000 Elevation = 20 200 feet ASL (this is the true altitude)
NOTE:
When an aircraft is operating in the standard pressure region with standard pressure set on the altimeter subscale, the term “flight level” is used in lieu of “altitude” to express its height. Flight level is always expressed in hundreds of feet. For example FL 250 represents an altimeter indication of 25 000 feet; FL 50, an indication of 5 000 feet.
The correct answer is: 13 200 feet
During a flight over the sea at FL135 the true altitude is 13 500 feet ASL with a local altimeter setting of 30.08 in Hg. What is known about the air mass in which the aircraft is flying?
L135 implies that the altimeter setting is 29.92 in Hg. The pressure altitude is 13 500 feet.
Local altimeter setting is 30.08 in Hg
From above information we can calculate the indicated altitude.
29.92 - 30.08 = - 0.16 x 1 000 = -160 feet Working backwards to get indicated not PA so add
13 500 feet + 160 = 13 660 feet indicated
Since the true altitude is lower, the indicated is higher, the temperature must be below or colder than ISA.
The term flight level (FL) is used when the altimeter setting is 29.92 in Hg. Flight levels are used in high level airspace at 18 000 feet ASL and above, and in Northern Domestic Airspace from the surface up when in cruise.
On the E6B if you line up the true altitude on the outside scale with the indicated/calibrated altitude on the middle scale you will see that in the altitude calculations window that PA of 13 500 lines up near to -12 C, standard temp at 13 500 feet (13.5 x 2/1000 = 27 from 15 = -12). Now if you apply the altimeter setting to the indicated/calibrated. Higher setting means higher altitude shown, so 13 660 feet. And you align that indicated/calibrated altitude to the true 13 500 feet on the outside scale. You will notice that the temperature is colder than standard. Not by much.
The correct answer is: The air mass is colder than ISA.
An aerodrome at 984 feet ASL has an altimeter setting of 30.54 in Hg at standard temperature. If the temperature dropped 12.5°C the station pressure most likely would be
Station pressure is the pressure for that elevation (elevation does not change). When temperature decreases the pressure levels change their spacing, move closer together (air is contracting). Since the pressure level height drops but elevation stays constant that means that the elevation is now in a lower pressure.
The altimeter shows pressure level and indicates it by height above sea level. When doing circuits a pilots flies the indicated altitude for the circuit height. In the winter the circuit height AGL is a lot lower even though the altimeter is still indicating circuit height. The colder air has brought the pressure level down, which the aircraft is flying, but the elevation has not changed so the aircraft is now closer to the surface. If the pilot were to climb to the same height AGL as in the summer the altitude on the altimeter would read higher than circuit height, because the pressure dropped.
The correct answer is: less than 30.54 in Hg.
An aircraft is flying around the Alps at the same level as the summit on a hot day. The altimeter would indicate
a lower altitude than the summit.
An inversion is characterized by
an increasing temperature with increasing altitude
A significant inversion at low height is a characteristic of
nocturnal radiation.
A condition that is present when a local parcel of air is stable is
Stable air is associated with an inversion, thus heating of the stable air mass does not result in convection (vertical movement), until heated above the temperature of the inversion - at this point the air mass becomes unstable.
The correct answer is: that the parcel of air resists convection.
The radiation of the sun heats the
surface of Earth which then heats the air in the troposphere.
The stability of the atmosphere can be determined by the
ambient temperature lapse rate.
Horizontal differences in the mean temperature of a layer are caused by
differential heating of Earth's surface.
Convective activity over land in the mid-latitudes is greatest in the
summer during the afternoon.
How does temperature vary with increasing altitude in the ICAO standard atmosphere below the Tropopause?
Decreases
An inversion is
an increase of temperature with height.
An isothermal layer is a layer of air in which the temperature
remains constant with height.
A common cause of a ground or surface based temperature inversion is
terrestrial radiation on a clear night with no or very light winds.
The environmental lapse rate in the real atmosphere
varies with time. It is not fixed
Diurnal variation refers to
temperature variation by day and night.
A common location for an inversion is
in the Stratosphere.
Tropopause is an isothermal layer, temperature remains the same with an increase in height. The change in lapse rate (decrease in temp) to isothermal (constant temp) is how the tropopause is found.
Wake turbulence would create colder air on top and warmer air on the bottom, the rising air would expand and cool and the subsiding are would be compressed and warmed.
Cumulus cloud base forms when the temperature cools to the dew point as the air rises, convection, and cools.
A characteristic associated with a temperature inversion is
stability.
Which statement regarding heat distribution is false?
Heating variation is fairly uniform throughout most land areas.
The heat of the Earth is transferred upwards largely by
Radiation does transfer heat upwards but convection is what takes the heat to the higher levels. Radiation is only low level.
The correct answer is: convection.
The incoming . . . . . radiation from the sun's rays are re-radiated into the atmosphere as infrared radiation which has a . . . . . wavelength than the incoming solar radiation.
shortwave, longer
Advection is the
horizontal motion of air.
Variations in heating of the atmosphere with respect to seasons is caused by the
tilt of Earth's axis.
Convert 30°F into Celsius.
-1°C
Not a means of cooling the atmosphere is
Adiabatic refers to a parcel of air that is not affected (in temperature or moisture) by the surrounding air. So as a parcel rises or falls the change in temperature is only caused by expanding (cooling) or contracting (warming).
Radiation (ground warming or cooling air) and advection (horizontal movement of air over warmer or cooler ground) both can warm and cool the atmosphere.
Where as Convection is rising air. As air rises it will expand and cool but it will still be warmer than the surrounding air. Which means it will be adding heat to the higher levels of the atmosphere, not cooling it.
The correct answer is: convection.