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100 Cards in this Set

  • Front
  • Back
The primary cause of all changes in the earth's weather is
Variation of solar energy received by the earth's regions
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
Coriolis
What relationship exists between the winds at 2,000 feet above the surface and the surface winds
The winds at 2,000 feet tend to parallel the isobars while the surface winds cross the isobars at an angle toward lower pressure and are weaker
winds at 5,000 feet AGL on a particular flight are southwesterly while most of the surface winds are southernly. This difference in direction is primarily
friction between the wind and the surface
What causes surface winds to flow across the isobars at an angle rather than parallel to the isobars
Surface friction
An air mass is a body of air that
Covers an extensive area and has fairly uniform properties of temperature and moisture.
A characteristic of the stratosphere is
relatively small changes in temperature with an increase in altitude
A jet stream is defined as wind of
50 knots or greater
The average height of the troposphere in the middle latitudes is
37,000 feet
The strength and location of the jet stream is normally
weaker and farther north in the summer
Which feature is associated with the tropopause
abrupt change in temperature lapse rate
Which weather phenomenon is always associated with the passage of a frontal system
a wind change
Which is a characteristic of a low-level wind shear as it relates to frontal activity
with a warm front, the most critical period is before the front passes the airport
Frontal waves normally form on
slow moving cold fronts or stationary fronts
Where do squall lines most often develop
ahead of a cold front
Which are characteristics of an unstable cold air mass moving over a warm surface
Cumuliform clouds, turbulence, and good visibility
What are characteristics of stable air
poor visibility, steady precipitation, and stratus-type clouds
What type clouds can be expected when an unstable air mass is forced to ascend a mountain slope
clouds with extensive vertical development
Which is a characteristic of stable air
stratiform clouds
the general characteristics of unstable air are
good visibility, showery precipitation, and cumuliform-type clouds
What type of clouds will be formed if very stable moist air is forced up slope
stratified clouds with little vertical development
steady precipitation, in contrast to showers, preceding a front is an indication of
stratiform clouds with little or no turbulence
what enhances the growth rate of precipitation
upward currents
Which of the following combinations of weather producing variables would likely result in cumiliform-type clouds, good visibility,rain showers, and possible clear-type icing in clouds
unstable, moist air and orographic lifting
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
Stability can be determined from which , measurement of the atmosphere
ambient lapse rate
what are some characteristics of unstable air
turbulence and good surface visibility
Unsaturated air flowing up slope will cool at the rate of approximately (dry adiabatic rate)
3' per 1,000 feet
what feature is associated with a temperature inversion
a stable layer of air
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
a temperature inversion will normally form only
in stable air
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
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
What situation is most conducive to the formation of radiation fog
warm, moist air over low, flatland areas on clear, calm nights
The most frequent type of ground-or surface-based temperature inversion is that produced by
radiation on a clear,relatively still night
what types of fog depend upon wind in order to exist
advection fog and upslope fog
In what localities is advection fog most likely to occur
coastal areas
In which situation is advection fog most likely to form
an air mass moving inland from the coast in winter
Fog is usually prevalent in industrial areas because of
an abundance of condensation nuclei from combustion products
Which weather condition can be expected when moist air flows from relatively warm surface to a colder surface
fog
Under which condition does advection fog usually form
moist air moving over colder ground or water
the amount of water vapor which air can hold largely depends on
air temperature
Clouds, fog, or dew will always form when
water vapor condenses
To which meteorological condition does the term "dew point' refer
the temperature to which air must be cooled to become saturated
which conditions result in the formation of frost
Temperature of the collecting surface is below the dewpoint of surrounding air and the dewpoint is colder than freezing
what are the 4 families of clouds
high. middle, low, and those with extensive vertical development
which family of clouds is least likely to contribute to structural icing on an aircraft
high clouds
the presence of standing lenticular altocumulus clouds is a good indication of
very strong turbulence
the suffix "nimbus", used in naming clouds means a
rain cloud
Standing lenticular clouds, in mountainous areas, indicate
turbulence
which clouds have the greatest turbulence
cumulonimbus
a high cloud is composed mostly of
ice crystals
Fair weather cumulus clouds often indicate
turbulence at and below the cloud level
when is an airplane most likely to be struck by lightning
OAT between-5'C and +5'C
What are the requirements for the formation of a thunderstorm
sufficient moisture, an unstable lapse rate, and lifting action
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
Which procedure is recommended if a pilot should unintentionally penetrate embedded thunderstorm activity
set power for recommend turbulence penetration airspeed and attempt to maintain a level flight attitude
which thunderstorms generally produce the most severe conditions, such as heavy hail and destructive winds
squall line
which weather phenomenon is always associate with a thunderstorm
lightning
During the life cycle of a thunderstorm, which stage is characterized predominantly by downdrafts
dissipating
If squall lines are reported at your destination, what wind conditions should you anticipate
sudden increases in wind speed of at least 16 knots rising to 22 knots or more, lasting for at least 1 minute
What is indicated by the term "embedded thunderstorm"?
thunderstorms are obscured by massive cloud layers and cannot be seen
Which weather phenomenon signals the beginning of the mature stage of a thunderstorm
the start of rain at the surface
Which is true regarding the use of airborne weather-avoidance radar for the recognition of certain weather conditions
the radarscope provides no assurance of avoiding instrument weather conditions
In which meteorological environmental is aircraft structural icing most likely to have the highest rate of accumulation
freezing rain
Test data indicate 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
which precipitation type normally indicates freezing rain at higher altitudes
Ice pellets
What is an operational consideration if you fly into rain which freezes on impact
temperatures are above freezing at some higher altitude
What temperature condition is indicated if wet snow is encountered at your flight altitude
the temperature is above freezing at your altitude
The presence of ice pellets at the surface is evidence that
there is freezing rain at a higher altitude
why is frost considered hazardous to flight operation
frost causes early airflow separation resulting in loss of lift
If the air temperature is +8'C 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
what happens to residual ice that remains after deice boots are inflated and shed ice
residual ice increases with an decrease in airspeed or temperature
The most susceptible surface of the aircraft for ice accumulation is the
tailplane
If you detect icing accumulation in flight, especially if the aircraft is not equipped with deicing system, you should
leave the area of precipitation, if able, or fly to an altitude where the temperature is above freezing
when conditions favoring the formation of ice are present, pilots should check for ice accumulation prior to flight. The best way to do this by
using a flashlight and watching for light reflection
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
Tailplane icing can be detected by A(N)
sudden uncommanded nose-down pitch
Tailplane icing can be detected by
elevator control pulsing, oscillations or vibrations
In an aircraft equipped with a pneumatic deicing system, the appropriate technique for removing ice is to
operate the pneumatic deicing system several times
a tailplane stall as the result of ice accumulation is most likely to occur during
approach and landing
with regards to landing, which is true
heavy icing on the leading edge is not as bad as light icing on the upper surface
should you experience uncommanded roll due to icing forward of the ailerons, the most appropriate response is to
reduce the angle of attack by increasing airspeed or extending flaps to the first setting
should you experience buffeting or vibrations after extending the flaps upon exiting or during icing conditions, the most likely reason is
Incipient tailplane stall
the best technique for using deicing boots is to
use them immediately upon visual detection of any ice
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
What is an important characteristic of wind shear?
It is an atmospheric conditions that may be associated with a low-level temperature inversion, a jet stream, or frontal zone
A pilot reporting turbulence that momentarily causes slight, erratic changes in altitude and/or attitude should report it as
light turbulence
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 atmospeher
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
where does wind shear occur
with either a wind shift or wind speed gradient at any level in the atmosphere
Hazardous wind shear is commonly encountered near the ground
during periods of strong temperature inversion and near thunderstorms
an aircraft that encounters a headwind of 45 knots, within a microburst, may expect a total shear across the microburst of
90 knots
Maximum downdrafts in a microburts encounter may be a strong as
6,000 feet per minute
what is the expected duration of an individual microburst
seldom longer than 15 minutes from the time the burst strikes the ground until dissipation
(Refer to figure 13 on page 302) the aircraft in position 3 will experience which effect in a microburst encounter
strong downdraft
(Refer to figure 13 on page 302) when penetrating a microburst, which aircraft will experience an increase in performance without a change in pitch or power
1
(Refer to figure 13 below) How will the aircraft in position 4 be affected by a microburst encounter
performance decreasing with a tailwind and downdraft
(Refer to figure 13 below) If involved in a microburst encounter, in which aircraft positions will the most severe downdraft occur
3 and 4
(Refer to figure 13 below) what effect will a microburst encounter have uponn the aircraft in position 4
strong tailwind