Gleim su 8 Aviation weather Flashcards
1
Q
The primary cause of all changes in the Earth’s weather is
A
variation of solar energy received by the Earth’s regions
2
Q
Which force, in the Northern hemisphere, acts at a right angle to the wind and deflects it to the right until parallel to the isobars
A
coriolis
3
Q
What relationship exists between the winds at 2,000 feet above the surface and the surface winds?
A
The winds at 2,000 feet tend to parallel the isobars while at the surface winds cross the isobars at an angle toward lower pressure and are weaker
4
Q
Winds at 5,000 feet AGL on a particular flight are southwesterly while most of the surface winds are southerly. This difference in direction is primarily due to
A
friction between the wind and the surface
5
Q
What causes surface winds to flow across the isobars at an angle rather than parallel to the isobars?
A
Surface friction
6
Q
An air mass is a body of air that
A
covers an extensive area and has fairly uniform properties of temperature and moisture
7
Q
A characteristic of the stratosphere is
A
relatively small changes in temperature with an increase in altitude
8
Q
The average height of the troposphere in the middle latitudes is
A
37,000 feet
9
Q
where do squall lines most often develop
A
ahead of a cold front
10
Q
The strength and location of the jet stream is normally
A
weaker and farther north in the summer
11
Q
a jet stream is defined as wind of
A
50 knots or greater
12
Q
Which feature is associated with the troposphere?
A
Abrupt change in temperature lapse rate
13
Q
Which weather phenomenon is always associated with the passage of a frontal system?
A
A wind change
14
Q
Which is a characteristic of low-level wind shear as it relates to frontal activity?
A
With a warm front, the most critical period is before the front passes the airport
15
Q
Frontal waves normally form on
A
slow moving cold fronts or stationary fronts
16
Q
When compared to winds at the surface, winds at 2,000 feet are
A
higher due to absence of friction
17
Q
Which are characteristics of an unstable cold air mass moving over a warm surface?
A
Cumuliform clouds, turbulence, and good visibility
18
Q
What are the characteristics of stable air?
A
Poor visibility, steady precipitation, and stratus-type clouds
19
Q
What type clouds can be expected when an unstable air mass is forced to ascend a mountain slope?
A
clouds with extensive vertical development
20
Q
which is a characteristics of stable air?
A
Stratiform clouds
21
Q
The general characteristics of unstable are
A
good visibility, showery precipitation, and cumuliform-type clouds
22
Q
What type of clouds will be formed if very stable moist air is forced up slope?
A
Stratified clouds with little vertical development
23
Q
Steady precipitation, in contrast to showers preceding a front is an indication of
A
stratiform clouds with little or no turbulence
24
Q
What enhances the growth rate of precipitation?
A
Upward currents
25
Which of the following combinations of weather producing variables would likely result in cumuliform-type clouds, good visibility, rain showers and possible clear-type icing in clouds
Unstable, moist-air, and orographic lifting
26
What determines the structure or type of clouds which form as a result of air being forced to ascend?
The stability of the air before lifting occurs
27
Stability can be determined from which measurement of the atmosphere?
Ambient lapse rate
28
what are some characteristics of unstable air?
turbulence and good surface visibility
29
Unsaturated air flowing up slope will cool at the rate of approximately (dry adiabatic lapse rate)
3 Celsius per 1,000 feet
30
What are the characteristics of an unstable atmosphere
a warm, humid air mass
31
clouds with extensive vertical development over mountainous terrain are a sign of
an unstable air mass
32
The stability of an air mass can usually be determined by
cloud types and the type of precipitation
33
What feature is associated with a temperature inversion?
A stable layer of air
34
Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?
Smooth air and poor visibility due to fog, haze, or low clouds
35
A common type of ground or surface-based temperature inversion is that which is produced by
ground radiation on clear, cool nights when the wind is light
36
A temperature inversion will normally form only
in stable air
37
An increase in temperature with an altitude increase
is indication of an inversion
38
Temperature and radiation variations over land with a clear sky typically lead to
minimum temperature occurring after sunrise
39
Which conditions are favorable for the formation of radiation fog?
Clear sky, little or no wind, small temperature/ dew point spread, and over a land surface
40
What situation is most conductive to the formation of radiation fog?
Warm, moist air over low, flatland areas on clear, calm nights
41
The most frequent type of ground- or surface- based temperature inversion is that produced by
radiation on a clear, relatively still night
42
What types of fog depend upon a wind in order to exist?
Advection fog and up slope fog
43
Which weather condition can be expected when moist air flows from a relatively warm surface to a colder surface?
Fog
44
Fog is usually prevalent in industrial areas because of
an abundance of condensation nuclei from combustion products
45
In what localities is advection fog most likely to occur?
Coastal areas
46
In which situation advection fog most likely to form?
An air mass moving inland from the coast in winter
47
Under which condition does advection fog usually form?
Moist air moving over colder ground or water
48
The amount of water vapor which air can hold largely depends on
air temperature
49
To which meteorological condition does the term "dew point" refer?
The temperature to which air must be cooled to become saturated
50
Clouds, fog, or dew will always form when
water vapor condenses
51
Which conditions result in the formation of frost?
Temperature of the collecting surface is below the dew point of surrounding air and the dew point is colder than freezing
52
Penetrating fog while flying an approach at night, you might experience the illusion of
pitching up
53
What are the four families of clouds?
High, middle, low, and those with extensive vertical development
54
Which family of clouds is least likely to contribute to structural icing on an aircraft?
high clouds
55
The presence of standing lenticular altocumulus clouds is a god indication of
very strong turbulence
56
Standing lenticular clouds, in mountainous areas, indicate
turbulence
57
The suffix "nimbus", used in naming clouds, means a
rain cloud
58
A high cloud is composed mostly of
ice crystals
59
Which clouds have the greatest turbulence?
Cumulonimbus
60
Fair weather cumulus clouds often indicate
turbulence at and below the cloud level
61
When is an airplane most likely to be struck by lightning?
OAT between -5 celsius and +5 celsius
62
If squalls are reported at your destination, what wind conditions should you anticipate?
Sudden increase in wind speed of at least 16 knots rising to 22 knots or more, lasting for at least 1 minute
63
What is an indication that downdrafts have developed and the thunderstorm cell has entered the mature stage?
Precipitation begins to fall from the cloud base
64
Which procedure is recommended if a pilot should unintentionally penetrate embedded thunderstorm activity?
Set power for recommended turbulence penetration airspeed and attempt to maintain a level flight attitude
65
Which thunderstorms generally produce the most severe conditions, such as heavy hail and destructive winds?
Squall line
66
Which weather phenomenon is always associated with a thunderstorms?
Lightning
67
During the life cycle of a thunderstorm, which stage is characterized predominantly by downdrafts?
Dissipating
68
Cumulus clouds often indicate
possible turbulence
69
What are the requirements for the formation of a thunderstorm?
Sufficient moisture, an unstable lapse rate, and a lifting action
70
What is indicated by the term "embedded thunderstorms"
Thunderstorms are obscured by massive cloud layers and cannot be seen
71
Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?
The start of rain at the surface
72
The use of airborne weather-avoidance radar
provides no assurance of avoiding instrument weather conditions
73
You are avoiding a thunderstorm that is in your flightpath. You are over 20 miles from the cell however, you are under the anvil of the cell. Is this a hazard?
Yes, hail can be discharged from the anvil
74
When approaching a cumulonimbus cell that is on your route of flight, a pilot should
circumnavigate the cell by at least 20 nautical miles
75
In which meteorological environment is aircraft structural icing most likely to have the highest rate of accumulation?
Freezing rain
76
Test data indicate that ice, snow, or frost having a thickness and roughness similar to medium or coarse sandpaper on the leading edge and upper surface of an airfoil can
reduce lift by as much as 30 percent and increase by 40 percent
77
Which precipitation type normally indicates freezing rain at higher altitudes?
ice pellets
78
What visual clue would alert a pilot to the presence of large supercooled water droplets?
Formation of a glossy, transparent ice
79
When large supercooled water droplets (SLD) are present in temperatures below +5 Celsius, outside air temperature, what type of icing would be expected to form?
Ice that is glossy, clear, or trasnlucent
80
Which of the following would be an accurate description of supercooled large droplets (SLD)?
Subfreezing water drops greater than 50 micrometers located in or below clouds
81
What is an operational consideration if you fly into rain which freezes on impact?
Temperatures are above freezing at some higher altitude
82
What temperature condition is indicated if wet snow is encountered at your flight altitude?
The temperature is above freezing at your altitude
83
The presence of ice pellets at the surface is evidence that
there is freezing rain at a higher altitude
84
Why is frost considered hazardous to flight operation?
Frost causes early airflow separation resulting in a loss of lift
85
If the air temperature is +8 degrees Celsius at an elevation of 1,350 feet and a standard (average) temperature lapse rate exists, what will be the approximate freezing level?
5,350 feet MSL
86
A pilot who experiences tailplane icing on the approach should
disengage the autopilot and retract flaps
87
When using inflight deicing systems in icing conditions, you should be aware that
there will be residual or some stage of intercycle ice on the wings
88
What happens to residual ice that remains after deice boots are inflated and shed ice?
Residual ice increases with a decrease in airspeed or temperature
89
On which surface of the aircraft could a pilot generally expect to see the first sign of ice accumulation?
Pitot tube
90
Tailplane icing can be detected by a(n)
sudden uncommanded nose-down pitch
91
What types of surfaces are most likely to see the first signs of ice accumulation?
Small narrow areas
92
While flying a standard instrument departure procedure (DP) you encounter icing conditions and the autopilot is engaged, you should
disengage the autopilot
93
The most susceptible surface of the aircraft for ice accumulation is the
tailplane
94
If you detect icing accumulation in flight, especially if the aircraft is not equipped with a deicing system, you should
leave the area of precipitation, if able, or fly to an altitude where the temperature is above freezing
95
In an aircraft equipped with a pneumatic deicing system, the appropriate technique for removing ice is to
operate the pneumatic deicing system several times
96
To recover from a tailplane stall brought on by ice accumulation, the pilot should
retract the flaps and increase power, but only to compensate for the reduction in lift
97
Tailplane icing can be detected by
elevator control pulsing, oscillations, or vibrations
98
A tailplane tall as the result of ice accumulation is most likely to occur during
approach and landing
99
With regards to icing, which is true?
Heavy icing on the leading edge is not as bad as light icing on the upper surface
100
When using deicing boots, the pilot should
activate the deicing system at the first indication of icing and do so in accordance with the manufacturer's guidance
101
Should you experience buffeting or vibrations after extending the flaps upon exiting or during icing conditions, the most likely reasons is
incipient tailplane stall
102
Which of the following is true about icing?
Small patches of ice sparsely distributed on the upper surface of the wing can cause asymmetrical stalls that result in roll control issues on takeoff
103
Should you experience uncommanded roll due to icing forward of the ailerons, the most appropriate responses is to
reduce the angle of attack by reducing the aircraft pitch, and if in a turn, roll wings level
104
Which is true concerning aircraft icing?
Small amounts of ice on the wing's surface usually result in correspondingly less performance degradation than larger amounts
105
The best technique for using deicing boots is to
use them immediately upon visual detection of any ice
106
The proper use of deicing boots should include
activation of the system at the first indication of icing and the continued cycling of the boots after leaving icing conditions to ensure any residual ice has been removed
107
How should deicing boots be used after exiting flight in icing conditions?
You should continue to cycle the boots several times to remove residual ice left behind after normal boot operation
108
Test data indicates that ice, snow, or frost having thickness and roughness similar to medium or coarse sandpaper on the leading edge and upper surface of an airfoil can
reduce lift by as much as 30 percent and increase drag by 40 percent
109
Ice tends to accumulate first on parts of the plane that are
small and narrow
110
During or after flight in icing conditions, vibration or buffeting that follows, but was not evident prior to, flap deployment is
an incipient tailplane stall as a result of negative tailplane angle after flap deployment
111
Where would you see the first sign of ice buildup?
The pitot tube
112
Roll upsets caused by ice accumulation forward of the ailerons can be remedied by
reducing the angle of attack by increasing airspeed or extending wing flaps to the first setting and rolling wings level
113
Which is true regarding Supercooled Large Droplets (SLD) and their accumulation
SLD can accrue aloft even if the droplets are not being observed at the surface
114
What is true regarding ice accumulation on a wing surface?
Small, visually imperceptible amounts of ice on a wing's surface during takeoff can result in significant performance degradation
115
If you experience icing during an approach, you should
retract the flaps as necessary and disengage the autopilot
116
What type of icing should be expected when you encounter supercooled large droplets (SLD) that splash or splatter on impact at temperature below +5 Celsius OAT?
Ice that forms on the wing aft of the active part of the deicing boots
117
Which of the following is true about icing characteristics?
Ice on the surface of the wing is virtually undetectable and causes a reduction in lift over the wing
118
After cycling of the deicing boots, residual ice will
increase as the airspeed or temperature decreases
119
On initial climbout after takeoff and with the autopilot engaged, you encounter icing conditions. In this situation, you can expect
Ice to accumulate on the underside of the wings due to the higher AOA
120
Where will the pilot first notice an accumulation of ice?
On the air temperature probe
121
Where is airplane icing most difficult to identify?
on the flat upper wing surface
122
A generally recommended practice for autopilot usage during cruise flight in icing conditions is
periodically disengaging the autopilot and hand flying the airplane
123
On the intitial climbout after takeoff with the autopilot engaged, you encounter icing conditions. In this situation, it is recommended that
the vertical speed mode be disconnected
124
Which is true about ice formation on a wing surface?
Ice or frost formation on a wing surface can result in localized, asymmetrical stalls on the wing resulting in roll control problems during lift off
125
When a climb or descent through an inversion or wind shear zone is being performed, the pilot should be alert for which of the following changes in airplane performance?
A sudden change in airspeed
126
What is an important characteristic of wind shear?
It is an atmospheric condition that may be associated with a low-level temperature inversion, a jet stream, or a frontal zone
127
What is an important characteristic of wind shear?
It may be associated with either a wind shift or a wind speed gradient at any level in the atmosphere
128
Where does wind shear occur?
With either a wind shift or a wind speed gradient at any level in the atmosphere
129
Where can wind shear associated with a thunderstorm be found? Choose the most complete answer
On all sides of the thunderstorm cell and directly under the cell
130
Hazardous wind shear is commonly encountered near the ground
during periods of strong temperature inversion and near thunderstorms
131
When climbing or descending through an area of possible wind shear, the pilot should be aware of
a rapid change of airpspeed
132
Which is a characteristic of low-level wind shear as it relates to low-level temperature inversions?
It allows airspeed to go above normal climb and approach speed
133
A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or altitude should report it as
light turbulence
134
(refer to figure 13 above) How will the aircraft in position 4 be affected by a microburst encounter?
Performance decreasing with a tailwind and downdraft
135
(refer to figure 13 above) When penetrating a microburst, which aircraft will experience an increase in performance without a change in pitch or power?
1
136
(refer to figure 13 above) The aircraft in position 3 will experience which effect in a microburst encounter?
Strong downdraft
137
(refer to figure 13 above) What effect will a microburst encounter have upon the aircraft in position 4?
Strong tailwind
138
(refer to figure 13 on page 366) If involved in a microburst encounter, in which aircraft positions will the most severe downdraft occur?
3 and 4
139
An aircraft that encounters a headwind of 45 knots, within a microburst, may expect a total shear across the microburst of
90 knots
140
Maximum downdrafts in a microburst encounter may be as strong as
6,000 feet per minute
141
What is the expected duration of an individual microburst?
Seldom longer than 15 minutes from the time the burst strike the ground until dissipation
142
As you approach an airport to land, you observe a convective cloud over the airport with virga below it. This could indicate
the presence of a microburst
