68 Questions
What meteorological quantity is extremely important for determining icing potential?
Cloud liquid water content
At what temperature range does most icing take place due to the need for ice nuclei?
-20° to 0° C
What droplet size has a significant influence on icing conditions?
40 microns
Why is it difficult to quantify liquid water content in clouds?
It is always below freezing temperature
What is the physical limit to icing regarding temperature?
-40° C
What is the main reason that small droplets tend to be swept around the airframe?
They have little mass and momentum.
In which altitude range do 50% of icing cases typically occur?
5000 feet to 13,000 feet
What causes rime ice to have a milky, opaque appearance?
Instantaneous freezing with air trapping
Under what conditions is clear ice most likely to form?
High water content and large droplet size
Why is the removal of clear ice considered difficult?
The ice particles are embedded in it, creating a rough accumulation.
What type of icing results from encountering both rime and clear icing along a flight path?
Mixed Icing
What temperature range is associated with clear icing based on Table 2.10?
-10ºC to 0ºC
Which altitude range is considered optimal for encountering icing conditions?
-5000 feet to 13,000 feet
Why is rime ice considered lightweight and brittle?
It quickly traps air during freezing.
What makes clear ice particularly hazardous compared to other types of icing?
It is very heavy and hard to remove.
What is the primary characteristic of supercooled large droplet (SLD) ice?
Large droplets forming a lumpy texture disrupting airflow
Which type of precipitation is most often associated with the warm layer process during the cold season?
Freezing rain
Which type of clouds mostly contain ice crystals and produce little icing?
Cirrostratus clouds
What is the maximum depth of continuous icing conditions in stratiform cloud layers?
6000 feet
How do clouds typically contribute to the collision-coalescence process of droplet growth?
By having a wide distribution of drop sizes resulting in different fall speeds
What is the key difference between SLD formation through the warm layer process and collision-coalescence?
The presence of an ice phase is required only in the warm layer process
What type of environment often results in favorable conditions for supercooled large droplet (SLD) formation through warm intrusions aloft?
Stable air masses
Which type of clouds are often observed to have both rime and mixed icing formations?
Stratiform clouds
In which situation is flying between layers of multiple stratus clouds usually impossible?
When layers are densely packed with no gaps
What combination of factors is likely to produce a high probability of icing?
Upward vertical motion, adequate moisture, CAA
What products are used to Identify CAA using radar?
Base velocity and VAD Wind Profile (VWP)
Which product can assist in identifying CAA by showing winds backing with height?
VAD Wind Profile (VWP)
Which rule of thumb suggests forecasting rime icing based on temperature?
$-15°C < \text{Temperature at flight level}$
How can vertical cross sections be helpful in evaluating icing potential?
By showing temperature and dew point depressions
What type of icing is likely when temperatures at flight level are between 0°C and -8°C in cumuliform clouds?
Clear icing
In which regions is the possibility of icing increased according to the text?
Along frontal cloud shields and near low-pressure centers
What does a S-shaped pattern in the zero isotach indicate according to the text?
$CAA$
What are the key atmospheric phenomena combined in the quick-reference icing flowchart according to the text?
$Radar reflectivity and velocity products$
Where does the most severe icing occur in cumulus clouds?
In the upper half of the cloud
In which type of clouds is icing more variable due to factors depending on cloud's development stage?
Cumulus clouds
What type of icing rarely occurs in cirrus clouds?
Moderate icing
Where does light rime icing occur in warm frontal systems?
300 miles ahead of the warm frontal surface position
In what type of clouds is clear icing more prevalent than rime icing associated with cold fronts?
Stratocumulus clouds
Where is moderate icing most likely to occur in cold frontal systems?
Directly above the frontal zone
Which factor contributes to the likelihood and severity of icing in clouds over mountainous regions?
Upward vertical motion on windward side of mountain ranges
What is a characteristic of icing conditions in stratiform clouds of a widespread, slow-moving cold frontal cloud shield?
Similar to cirrus cloud conditions
When does freezing drizzle and rain most often occur with frontal systems?
With both warm fronts and shallow cold fronts
Which type of frontal system is associated with sporadic or continuous icing depending on stability?
Warm fronts
What type of cloud types are associated with moderate rime icing according to the text?
CB, CU, ST
In what atmospheric condition is light frost likely to sublimate on aircraft?
When cirrus, cirrocumulus, or cirrostratus clouds are present
What weather condition would likely result in light rime icing according to the text?
Altocumulus clouds with a dew-point depression greater than 0°C
What does it indicate when the temperature curve lies to the left of the –8D curve in a subfreezing layer?
The layer is supersaturated with respect to ice
When is light frost likely to form through direct sublimation of water vapor?
In cloudless regions
What conditions lead to light rime icing according to the text?
Dew-point depression greater than 0°C and temperature curve lies to the right of the –8D curve
What is the purpose of determining the height of the -22°C isotherm in aviation weather forecasting?
To assess the potential for icing conditions
In aviation weather forecasting, what does a ring of enhanced reflectivity (30 to 45 dBZ) around the Radar Data Acquisition Unit signify?
Formation of the bright band
What is the significance of the vertical profile where the -8D curve is to the right of the temperature curve on a Skew-T diagram?
Icing conditions are likely
How does visible imagery assist in identifying icing potential during daytime hours?
By showing brighter clouds with higher thickness and water content
What do noisy differential reflectivity (ZDR) values and low correlation coefficient (CC) values on dual-polarization base data indicate in aviation weather forecasting?
Identification of the melting layer
What does the presence of a weak signature in the specific differential phase (KDP) product suggest in aviation weather analysis?
Potential freezing level
Why is determining the height of the freezing level important in aviation weather forecasting?
To assess areas where icing conditions might occur
What does the presence of icing below the melting layer signify in aviation weather forecasting?
Primary precipitation type being rain
How do embedded lighter gray shades on visible imagery relate to icing conditions?
Correlate with heavier icing due to large cloud droplet sizes or thicker clouds
In aviation weather forecasting, what does a ring of noisy differential reflectivity (ZDR) values and low correlation coefficient (CC) values indicate?
Location of the melting layer
What is the main effect of induction icing on an aircraft's engine?
Power loss due to blocking of air intake
In what conditions can carburetor icing occur?
Low temperatures and high relative humidity
What is a consequence of carburetor icing?
Reduced engine performance or total engine failure
How does ice in the carburetor affect the engine?
Partially or totally blocks air/fuel mixture flow
When does carburetor icing form?
In cold and moist conditions
What atmospheric conditions favor carburetor icing?
-7C (20F) and above with high humidity
What can happen if ice forms on air intake ducts of an aircraft?
Decreased air intake due to ice blockage
What is the potential consequence of ice breaking free from intake surfaces?
'Foreign Object Damage' to internal engine components
How does carburetor icing impact engine performance?
'Total' blocking of the air/fuel mixture flow into the engine
Learn about the factors that influence aircraft icing severity and type, including properties of the aircraft and atmospheric conditions. Understand the importance of liquid water content in clouds for determining icing potential.
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