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ATPL 50 METEOROLOGY |
| 50.01 THE ATMOSPHERE |
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1
The cloud base, reported in the metar, is the height above
Airfield level |
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2
The troposphere
Has a greater vertical extent above the equator than above the poles |
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3
What values are used for the forecasted wind at higher levels?
Direction relative to true north and speed in knots |
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4
What is the approximate composition of the dry air by volume in the troposphere ?
21 % oxygen, 78 % nitrogen, and the rest other gasses |
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5
The wind direction in a metar is measured relative to
True north |
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6
Clear ice forms on an aircraft by the freezing of :
Large supercooled water drops |
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7
Under which conditions would you expect the heaviest clear ice accretion to occur in a cb?
Between -2° c and - 15° c |
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8
The thickness of the
Latitude |
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9
The troposphere is the
Part of the atmosphere stratosphere and the thermosphere |
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10
The tropopause is a height
Temperature ceases to level at which |
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11
Relative humidity depends on
Moisture content and temperature of the air |
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12
The difference between temperature and dewpoint is greater in
Dry air |
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13
Rime ice forms through aircraft surfaces of
Small supercooled the freezing onto |
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14
How does a pilot react to heavy freezing rain at 2000 ft/agl, when he is unable to deice, nor land?
He turns back before the aircraft loses manoeuvrability. |
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15
Rising air cools because
It expands |
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16
In the mid-latitudes the stratosphere extends on an average from
11 to 50 km |
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17
The tropopause is lower
Over the north pole than over the equator |
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18
Relative humidity at a given temperature is the relation between
Actual water vapour content and saturated water vapour content |
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19
On the approach, the surface temperature is given as -5° c. the freezing level is at 3000 ft/agl. at 4000 ft/agl, there is a solid cloud layer from which rain is falling. according to the weather briefing, the clouds are due to an inversion caused by warm air sliding up and over an inclined front. w ould you expect icing? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
Yes, between ground level and 3000 ft/agl. |
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20
Atmospheric soundings give the following temperature profile : 3000 ft +15° c 6000 ft +8° c 10000 ft +1° c 14000 ft -6° c 18000 ft -14° c 24000 ft -26° c at which of the following flight levels is the risk for aircraft icing, in cloud, greatest?
Fl 150 |
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21
At about what geographical latitude as average is assumed for the zone of prevailing westerlies?
50° n. |
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22
What of the following is the most important constituent in the atmosphere from a weather stand-point ?
W ater vapour |
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23
The average height of
11 km the tropopause at 50° n is about |
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24
The height and the tropopause are respectively in the order of
16 km and -75° c over the poles |
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25
The type of icing that occurs in dense clouds with large supercooled drops that have a temperature of -5° c is most likely to be
Clear ice |
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26
Large supercooled water drops, which freeze on impact on an aircraft, form
Clear ice |
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27
Clear ice forms as a result of
Supercooled water droplets spreading during the freezing process |
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28
An airmass is stable when weaker and disappears.
The vertical motion of a per 100 m tends to become |
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29
An airmass is unstable when
An ascending parcel of considerable height. |
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30
Hoar frost forms on an aircraft as a result of
Water vapour turning directly into ice crystals on the aircraft surface |
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31
Clear ice is dangerous because it
Is heavy and is difficult to remove from the aircraft surfaces |
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32
How does freezing rain develop?
Rain falls through a layer where temperatures are below 0° c |
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33
Glaze or clear ice is formed when supercooled droplets are
Small and at a temperature just below freezing |
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34
A vertical temperature profile indicates the possibility of severe icing when the temperature profile
Intersects the 0° c isotherm twice |
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35
What flying conditions may be encountered when flying in cirrus clouds?
Average horizontal visibility more than 1000 m. nil icing. |
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36
During the formation of rime ice in flight, water droplets freeze
Rapidly and do not spread out |
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37
Fallstreaks or virga are
Water or ice particles falling out of a cloud that evaporate before reaching the ground |
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38
When is the rvr reported at most airports? m.
When the meteorological visibility decreases below 1500 |
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39
In which layer is most of the atmospheric humidity concentrated ?
Troposphere. |
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40
How does the height of
It decreases from south throughout the year. |
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41
What is the type, intensity and seasonal variation of precipitation in the equatorial region ?
Rainshowers, hail showers and thunderstorms occur the whole year, but |
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42
The reason for the fact, that the icelandic low is normally deeper in winter than in summer is that
The temperature contrasts between arctic and equatorial areas are much greater |
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43
What, approximately, is the average height of the tropopause over the equator ?
16 km |
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44
A small supercooled cloud droplet that collides with an airfoil will most likely
Freeze immediately and create rime ice. |
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45
W hile descending through a cloud cover at high level, a small amount of a white and rough powderlike contamination is detected along the leading edge of the wing. this contamination is called:
Rime ice. |
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46
Two aircraft, one with a sharp wing profile (s), and the other with a thick profile (t), are flying through the same cloud with same true airspeed. the cloud consists of small supercooled droplets. which of the following statements is most correct concerning ice accretion ?
Aircraft s experiences more icing than t. |
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47
Hoar frost is most likely to form when
Taking off from an airfield with a significant ground inversion. |
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48
Which of the following factors have the greatest effect on the formation of the various types of ice on an aircraft ?
Cloud temperature and droplet size |
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49
Which one of the following statements concerning the formation of aircraft icing is most correct ?
A cloud consisting of both supercooled cloud droplets and ice crystals produces aircraft icing |
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50
A winter day in northern europe with a thick layer of stratocumulus clouds and temperature close to zero degrees c at ground level, you can expect:
A high probability for icing in clouds. severe icing in the upper part due to accumulation of large droplets. |
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51
Which of the following cloud types are most likely to produce light to moderate icing when they are not subject to orographic lifting and consist of supercooled cloud droplets?
Altocumulus and altostratus. |
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52
What is the meaning of the abbreviation "bkn"?
5 - 7 oktas. |
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53
What process in an air mass leads to the creation of wide spread ns, as and st cloud coverage?
Lifting |
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54
Which of the following cloud is classified as low level cloud ?
St |
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55
In which of the following conditions is moderate to severe airframe icing most likely to be encountered?
In nimbostratus cloud |
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56
(for this question use annex 050-2065a) what is the classification of the airmass affecting position "q" at 0600 utc?
Tropical maritime. |
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57
Which one of the following statements applies to the tropopause?
It separates the troposphere from the stratosphere |
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58
Where does polar continental air originate? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
Siberian landmass. |
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59
Where is the source of summer?
The southern balkan tropical continental air that affects europe in |
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60
In which air mass are extremely low temperatures encountered? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
Polar continental air. |
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61
What are the typical differences between the temperature and humidity between an air mass with its origin in the azores and an air mass with its origin over northern russia ? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
The air of the azores is warmer and more humid than the north- russian air. |
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62
Which of the following clouds may extend into more than one layer?
Nimbostratus. |
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63
Which form of precipitation from clouds containing only water is most likely to fall in mid-latitudes?
Drizzle. |
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64
Which of the following is a cause of stratus forming over flat land?
Radiation during the night from the earth surface in moderate |
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65
Which of the following processes within a layer of air may lead to the building of cu and cb clouds?
Convection. |
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66
What are the characteristics of cumuliform clouds?
Large water droplets, instability, turbulence, showers and mainly clear ice. |
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67
Which of the following types of clouds are evidence of unstable air conditions?
Cu, cb. |
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68
Which of the following clouds are classified as medium level clouds in temperate regions ? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
As, ac. |
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69
(for this question use annex 050-1914a) which one of the displayed cloud forms is representative of altocumulus castellanus?
3. |
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70
A plain in western elevation of 500 m (1600 ft) above sea level is covered with a uniform ac layer of cloud during the summer months. at what height above the ground is the base of this cloud to be expected?
15000 - 25000 ft above the terrain. |
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71
What is the main
Ice crystals. |
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72
What is the relationship between meteorological visibility (met.vis.) and rvr in homogeneous fog?
The met. vis. is generally less than the rvr. |
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73
The wind indicator for a weather observation receives the measured value from an anemometer. where is this instrument placed?
On a mast 8-10 m above the ground. |
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74
Which of the following cloud types can project up into the stratosphere?
Cumulonimbus |
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75
Runway visual range (rvr) is
Usually better than meteorological visibility |
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76
Freezing fog exists if fog droplets
Are supercooled |
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77
What does dewpoint mean? which a mass of air which ice melts. (danger of icing). which the relative
The temperature to |
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78
What is the boundary layer between troposphere and stratosphere called?
Tropopause. |
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79
Which of the following is the definition of relative humidity ?
Ratio between the actual mixing ratio and the saturation mixing |
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80
The relative humidity of a sample air mass is 50%. how is the relative humidity of this air mass influenced by changes of the amount of water vapour in it?
It increases with increasing water vapour. |
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81
How, if at all, is the relative humidity of an unsaturated airmass influenced by temperature changes?
It decreases with increasing temperature. |
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82
How does relative humidity and the dewpoint in an unsaturated air mass change with varying temperature?
When temperature increases, the relative humidity decreases, and the dewpoint remains constant. |
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83
When a given mass of effect will it have on relative humidity? afternoon an air temperature of +12° c and a dew point of +5° c were measured. what temperature change must occur during the night in order to induce saturation?
It decreases. +6° c. |
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84
Clouds, classified as
The surface to 6500 ft |
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85
The presence of altocumulus lenticularis is an indication of the
Presence of mountain waves |
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86
The presence of altocumulus castellanus indicates
Instability in the middle troposphere |
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87
What type of cloud is being described ? a generally grey cloud layer with fairly uniform base and uniform appearance, which may give drizzle or snow grains. when the sun is visible through the cloud, the outline is clearly discernible. sometimes it appears in the form of ragged patches.
Stratus |
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88
Cumulus clouds are an indication for
Up and downdrafts |
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89
Which of the following are medium level clouds ?
Altostratus and altocumulus |
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90
Strongly developed cumulus clouds are an indication of
Instability in the atmosphere |
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91
A cumulonimbus cloud at moderate latitudes in summer contains
A combination of ice crystals, water droplets and supercooled water droplets |
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92
Altostratus clouds are classified as
Medium level clouds |
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93
Convective clouds are formed
In unstable atmosphere |
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94
The maximum amount of water vapour that the air can contain depends on the
Air temperature |
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95
In an unstable layer there are cumuliform clouds. the vertical extent of these clouds depends on the
Thickness of the unstable layer |
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96
Dew point is defined as
The lowest temperature which moist air must be cooled to become saturated at a given pressure |
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97
Considering the north atlantic region between 30° n and 65°n together with the adjacent land areas during winter, the normal disposition of the main anticyclones at the surface is
Azores, siberia |
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98
Considering the north atlantic region between 30° n and 65° n and the adjacent land areas during mid-summer, the predominant pressure systems are
Azores high and weak low over ne canada |
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99
Select the answer which you consider will complete correctly the following statement in relation to the main pressure systems affecting the north atlantic region between 30° n and 65°n. during winter the predominant mean low pressure system at the surface is usually centred over
Iceland / greenland |
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100
In which of the following areas do surface high pressure systems usually predominate over the north atlantic region between 30° n and 65° n and the adjoining land areas during the northern summer?
Azores, se usa, sw europe |
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101
(for this question use of the route indicated from 30° e to 50° e, the upper winds in january above fl 300 are most likely to be
A subtropical westerly |
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102
Which layer of the atmosphere contains more than 90 per cent of all water vapour?
Lower stratosphere |
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103
What are the images of satellites provided daily by the service used for?
To locate fronts in areas with few weather |
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104
When will the surface wind in a metar record a gust factor ?
When gusts are at least 10 knots above the mean wind speed |
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105
At what degree of icing can icao"s "no change of course and altitude necessary" recommendation be followed?
Light |
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106
At what degree of icing should icao"s "change course and/or altitude immediately" instruction be followed?
Severe |
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107
At what degree of icing should icao"s "change of course and/or altitude desirable" recommendation be followed? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
Moderate |
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108
(for this question use annex 050-4314a) continuous freezing rain is observed at an airfield. which of the four diagrams is most likely to reflect temperatures above the airfield concerned? 1 switzerl which of the following pe +fzra gr shsn 0 -1 0 0 conditions is most likely to cause airframe icing ? 1 switzerl in which of these cloud ns cs as sc 0 -1 0 0 types can icing be virtually ruled out? 1 switzerl in which of these cloud cu ci sc ns 0 -1 0 0 types can icing be virtually ruled out?
Diagram d) |
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109
In which of these temperature bands is ice most likely to form on the aircraft"s surface?
0° c to -10° c |
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110
You have been flying for some time in dense layered cloud. the outside air temperature is -25° c. which of the following statements is true? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
Severe airframe icing is unlikely under these conditions |
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111
Which of the following causes echoes on meteorological radar screens?
Hail |
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112
Going from the equator to the north pole, the altitude of the tropopause
Decreases and its temperature increases |
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113
What is the approximate speed of a 40-knot wind, expressed in m/sec?
20 m/sec |
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114
What is the approximate speed of a 90 km/h wind, expressed in knots?
50 kt |
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115
What is the approximate speed of a 25-knot wind, expressed in kilometres per hour? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
45 km/h |
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116
An airborne weather radar installation makes it possible to detect the location of hail
Zones of precipitation, particulary liquid-state precipitation, and also their intensity |
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117
W hile approaching your target aerodrome you receive the following message: rvr runway 23: 400m this information indicates the
Length of runway which a pilot in an aircraft on the ground would see, on the threshold of runway 23. |
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118
Which of the following cloud types is a medium level cloud ?
As |
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119
Which of the following cloud types is found at high levels? subject/sec aragraph wording domanda rispostaa rispostab rispostac rispostad ck1 ck2 ck3 ck4
Ci |
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120
A plain in western europe with an average height of 500 m (1600 ft) above sea level is covered with a uniform cc layer of cloud during the summer months. at what height above the ground is the base of this cloud to be expected?
15000 - 35000 ft above the terrain |
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121
A plain in western europe with an average height of 500 m (1600 ft) above sea level is covered with a uniform sc layer of cloud during the summer months. at what height above the ground is the base of this cloud to be expected?
1500 - 7000 ft above ground |
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122
Which of the following types of cloud can extend over the low, medium and high cloud levels ?
Cb |
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123
Which types of clouds are typical evidence of stable air conditions?
St, as |
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124
Which of the following statements is true of the dew point of an air mass?
It can only be equal to, or lower, than the temperature of the air the air temperature is |
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125
In which environment is aircraft structural ice most likely to have the highest rate of accretion ?
Freezing rain. |