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Questions and Answers
What does a mid-latitude cumulonimbus cloud typically contain?
What does a mid-latitude cumulonimbus cloud typically contain?
Which cloud type is classified as high level?
Which cloud type is classified as high level?
Which of the following clouds are classified as medium level clouds?
Which of the following clouds are classified as medium level clouds?
When flying in cirrus clouds, which flying condition may be encountered?
When flying in cirrus clouds, which flying condition may be encountered?
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What is the expected height above ground for the base of a uniform SC cloud layer in Western Europe with an average height of 500m?
What is the expected height above ground for the base of a uniform SC cloud layer in Western Europe with an average height of 500m?
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Clouds that extend over low, medium, and high levels are classified as which type?
Clouds that extend over low, medium, and high levels are classified as which type?
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Which clouds are evidence of stable air conditions?
Which clouds are evidence of stable air conditions?
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What atmospheric condition is indicated by strongly developed cumulus clouds?
What atmospheric condition is indicated by strongly developed cumulus clouds?
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What are fall-streaks or virga?
What are fall-streaks or virga?
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What layer defines low-level clouds bases?
What layer defines low-level clouds bases?
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Which of the following is a cause of stratus forming over flat land?
Which of the following is a cause of stratus forming over flat land?
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What process in an air mass leads to the creation of wide spread NS, AS and ST cloud coverage?
What process in an air mass leads to the creation of wide spread NS, AS and ST cloud coverage?
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Which type of cloud is described as a generally grey cloud layer with a uniform base that can produce drizzle or snow grains?
Which type of cloud is described as a generally grey cloud layer with a uniform base that can produce drizzle or snow grains?
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Which of the following clouds are classified as medium level clouds in temperate regions?
Which of the following clouds are classified as medium level clouds in temperate regions?
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Which types of clouds are evidence of unstable air conditions?
Which types of clouds are evidence of unstable air conditions?
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Which displayed cloud form is representative of altocumulus castellanus?
Which displayed cloud form is representative of altocumulus castellanus?
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Which of the following processes within a layer of air may lead to the building of CU and CB clouds?
Which of the following processes within a layer of air may lead to the building of CU and CB clouds?
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Which of the following cloud types is classified as a medium level cloud?
Which of the following cloud types is classified as a medium level cloud?
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At what altitude range can high level clouds typically be found?
At what altitude range can high level clouds typically be found?
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What is the main composition of high level clouds?
What is the main composition of high level clouds?
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What are the characteristics of cumuliform clouds?
What are the characteristics of cumuliform clouds?
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If a uniform altocumulus cloud layer is present over a plain in Western Europe at 500m, how high above ground is the base of this cloud likely to be?
If a uniform altocumulus cloud layer is present over a plain in Western Europe at 500m, how high above ground is the base of this cloud likely to be?
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What does the presence of altocumulus lenticularis indicate?
What does the presence of altocumulus lenticularis indicate?
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In which scenario is moderate to severe airframe icing most likely to occur?
In which scenario is moderate to severe airframe icing most likely to occur?
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Cumulus clouds are an indication of what atmospheric condition?
Cumulus clouds are an indication of what atmospheric condition?
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What does the presence of altocumulus castellanus signify?
What does the presence of altocumulus castellanus signify?
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Which cloud type is typically associated with steady rain or snowfall?
Which cloud type is typically associated with steady rain or snowfall?
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How can one distinguish between altostratus and nimbostratus clouds?
How can one distinguish between altostratus and nimbostratus clouds?
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What effect does a thin coating of hoar frost have on wing lift?
What effect does a thin coating of hoar frost have on wing lift?
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Which type of precipitation is associated with the most severe icing conditions?
Which type of precipitation is associated with the most severe icing conditions?
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What type of icing will most likely be encountered after descending into humid air from very cold conditions?
What type of icing will most likely be encountered after descending into humid air from very cold conditions?
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At what altitude range is the probability of airframe icing highest when descending through clouds with a freezing level at FL 60?
At what altitude range is the probability of airframe icing highest when descending through clouds with a freezing level at FL 60?
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When flying into supercooled rain at temperatures below 0°C, what type of icing is most likely?
When flying into supercooled rain at temperatures below 0°C, what type of icing is most likely?
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What is the primary mechanism through which icing occurs in layered clouds?
What is the primary mechanism through which icing occurs in layered clouds?
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What type of ice is characterized by a white and rough powder-like contamination along the leading edge of the wing?
What type of ice is characterized by a white and rough powder-like contamination along the leading edge of the wing?
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Under which condition is an aircraft most susceptible to icing?
Under which condition is an aircraft most susceptible to icing?
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Which statement correctly describes a risk factor for aircraft icing?
Which statement correctly describes a risk factor for aircraft icing?
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When is hoar frost most likely to form?
When is hoar frost most likely to form?
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Which factor most significantly affects the formation of different ice types on an aircraft?
Which factor most significantly affects the formation of different ice types on an aircraft?
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In which situation do fog droplets exist in a state that defines freezing fog?
In which situation do fog droplets exist in a state that defines freezing fog?
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Which scenario presents a higher risk for icing based on cloud types?
Which scenario presents a higher risk for icing based on cloud types?
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For two aircraft flying through the same cloud, which wing profile is more likely to experience a greater accumulation of ice?
For two aircraft flying through the same cloud, which wing profile is more likely to experience a greater accumulation of ice?
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What condition contributes to the formation of clear ice?
What condition contributes to the formation of clear ice?
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Under which circumstances can moderate icing be safely tolerated according to ICAO recommendations?
Under which circumstances can moderate icing be safely tolerated according to ICAO recommendations?
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What is the primary cause of hoar frost formation on an aircraft?
What is the primary cause of hoar frost formation on an aircraft?
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Which statement is accurate regarding moderate-to-severe airframe icing?
Which statement is accurate regarding moderate-to-severe airframe icing?
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Which condition indicates the potential for severe icing based on a vertical temperature profile?
Which condition indicates the potential for severe icing based on a vertical temperature profile?
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Why is icing over hills often more severe than over flat terrain?
Why is icing over hills often more severe than over flat terrain?
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Under which condition does rime ice formation occur during flight?
Under which condition does rime ice formation occur during flight?
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Which mechanism correctly describes the formation of clear ice in freezing rain?
Which mechanism correctly describes the formation of clear ice in freezing rain?
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What effect does icing on wings typically have during flight operations?
What effect does icing on wings typically have during flight operations?
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What does icing on an aircraft typically cause?
What does icing on an aircraft typically cause?
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Which aircraft is likely to experience more icing?
Which aircraft is likely to experience more icing?
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What can be expected on a winter day in northern Europe with a thick layer of stratocumulus clouds at close to zero degrees C?
What can be expected on a winter day in northern Europe with a thick layer of stratocumulus clouds at close to zero degrees C?
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Which cloud types are most likely to produce light to moderate icing when not subject to orographic lifting?
Which cloud types are most likely to produce light to moderate icing when not subject to orographic lifting?
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At what degree of icing should ICAOs change course and/or altitude immediately?
At what degree of icing should ICAOs change course and/or altitude immediately?
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Clear ice forms on an aircraft by the freezing of which type of water?
Clear ice forms on an aircraft by the freezing of which type of water?
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What is a significant danger of clear ice on aircraft?
What is a significant danger of clear ice on aircraft?
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In which environment is there likely the highest rate of aircraft structural ice accumulation?
In which environment is there likely the highest rate of aircraft structural ice accumulation?
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Under what conditions should ICAOs be recommended to change course and/or altitude?
Under what conditions should ICAOs be recommended to change course and/or altitude?
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At which flight level is the risk for aircraft icing in cloud the greatest?
At which flight level is the risk for aircraft icing in cloud the greatest?
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What process leads to the formation of clear ice on an aircraft?
What process leads to the formation of clear ice on an aircraft?
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Study Notes
Cloud Formation and Description
- Stratus clouds often form over flat land at night due to radiation cooling from the Earth's surface combined with moderate wind.
- Widespread cloud coverage of Nimbostratus (NS), Altostratus (AS), and Stratus (ST) typically results from lifting processes in an air mass.
- Cumulus clouds indicate unstable air conditions, including cumulus (CU) and cumulonimbus (CB) types.
- Medium level clouds in temperate regions include Altostratus (AS) and Altocumulus (AC).
- Cumulonimbus clouds contain ice crystals, water droplets, and supercooled water droplets, especially in mid-latitudes during summer.
Cloud Types and Levels
- Low-level clouds extend from the surface up to 6500 ft, with Stratus (ST) classified as a low-level cloud.
- Medium-level cloud types include Altostratus (AS) and Altocumulus (AC).
- High-level clouds, such as Cirrus (CI), are primarily made up of ice crystals.
- Nimbostratus clouds can extend through multiple layers, offering steady precipitation.
Cloud Characteristics
- Altostratus clouds belong to medium-level clouds and can be distinguished by their higher cloud base and lighter precipitation compared to Nimbostratus.
- Cumuliform clouds indicate turbulence and instability, characterized by significant vertical development.
- Fall-streaks (virga) are water or ice particles that evaporate before reaching the ground.
Conditions Impacting Clouds
- Strongly developed cumulus can indicate atmospheric instability and the presence of vertical air movements.
- Altocumulus lenticularis suggests the presence of mountain waves, often associated with orographic effects.
- Moderate to severe airframe icing is likely encountered in Nimbostratus clouds.
Identifying Clouds
- Stratus clouds may produce drizzle or snow grains; Nimbostratus clouds produce continuous rain or snow.
- Altostratus can have a higher base than Nimbostratus, and precipitation from Altostratus, if present, is typically light.
- Cumulonimbus clouds can extend into the stratosphere, showing significant vertical development.
Summary of Key Facts
- Altostratus and Nimbostratus clouds can be confused; however, Altostratus typically has a higher cloud base and lighter precipitation.
- Cumulus clouds are indicative of up and downdrafts and generally signify unstable conditions.
- Understanding cloud types and their formation is essential for aviation safety and weather forecasting.
Aircraft Icing Types and Risks
- Contamination along wing surfaces can include rime ice, which occurs when small supercooled droplets freeze on impact.
- Aircraft are most susceptible to icing during level flight below rain-producing clouds with temperatures below zero degrees Celsius.
- The highest risk of icing arises from clouds containing both supercooled droplets and ice crystals.
Formation Conditions
- Hoar frost is likely to form from a ground inversion, particularly during takeoff.
- Key factors in the formation of various types of aircraft icing include cloud temperature and droplet size.
- Freezing fog is defined as existing when fog droplets are supercooled.
Ice Accretion Dynamics
- Aircraft with sharp wing profiles experience less icing compared to those with thick profiles when flying through supercooled droplet clouds.
- Significant icing is likely in stratus clouds during winter, particularly in northern Europe with temperatures near zero.
- Light to moderate icing typically occurs in altostratus and altocumulus clouds with supercooled droplets.
Severity and Guidelines
- ICAO recommendations indicate immediate course and altitude changes at the severe ice level.
- Clear ice forms predominantly from the freezing of large supercooled water drops, making it particularly dangerous due to its weight and removal difficulty.
- The heaviest clear ice accretion often occurs in cumulonimbus clouds at temperatures between -2°C and -15°C.
Environmental and Flight Considerations
- The rate of structural ice accumulation is highest in environments with freezing rain, leading to severe icing conditions.
- Pilots facing heavy freezing rain should turn back before experiencing a loss of maneuverability.
- During descent through humid air masses from very cold conditions, hoar frost is expected due to water vapor freezing onto cold surfaces.
Impact on Flight Performance
- Ice accumulation significantly increases the stalling speed of an aircraft, which can lead to dangerous flight conditions.
- A thin layer of hoar frost negatively affects wing lift, emphasizing the importance of ice removal prior to flight.
- Freezing rain poses the most severe icing threat, as large water drops freeze upon impact with aircraft surfaces.
Associated Risks
- Understanding the temperature profile in the atmosphere is crucial in predicting icing conditions, especially when the 0°C isotherm intersects multiple times.
- Orographic lifting enhances the severity of icing due to increased moisture retention in clouds above hilly terrains.
- Pilots must be aware of icing formations associated with various weather conditions and react appropriately to maintain safe flight operations.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on cloud formation and types in this quiz focused on Clouds and Fog. Questions cover various processes that lead to the formation of different cloud types and conditions. Ideal for aviation students and weather enthusiasts.
