14 - Meteorology 4

A greater intensity of turbulence is found while flying (mountain wave)

downwind into a mountain wave.

If you must cross a mountain ridge while strong winds are present, cross the ridge

at a 45° angle with at least 3 000 feet above the ridge.

When flying in mountainous areas pilots should be on the lookout for

strong downdrafts on the leeward side of the mountain.

Lenticular clouds often form

from 20 000 to 40 000 feet.

Mountain wave turbulence exists

on the lee side of a mountain.

Mountain waves having the largest amplitudes are found

between 3 000 to 6 000 feet above the ridge

The most severe turbulence with mountain waves is found

in the rotor areas.

The greatest amount of turbulence is typically found in

rotor clouds.

What can be expected regarding the airflow near a cap cloud?

Extremely strong downdrafts are present.

Which is not a factor contributing to the formation of mountain waves?

Select one:

a. Winds aloft increase with height.

b. The wind velocity on the windward side is 25 KT or more.

c. The wind is blowing within 30° of perpendicular to the mountains.

d. An unstable air mass layer exists aloft.

Question asking NOT a factor.
The unstable air aloft allows rising air to continue rising, so no barrier.

The correct answer is: An unstable air mass layer exists aloft.

Which condition would produce the smoothest flying?

Flight above the clouds.

Mechanical turbulence is formed when

wind encounters terrain or obstacles.

When approaching a mountain ridge it is safer to cross

on the windward side of the mountain.

Wind shear is a sudden change in the wind's

speed and/or direction.

Turbulence in the lower levels is to be expected when

cold air moves over a warm surface.

The turbulence reporting criteria known as severe is best described as

large abrupt changes, momentarily out of control.

The most severe mountain wave turbulence is encountered when flying

downwind.

The vertical extent of mechanical turbulence in the lower levels would be

greatest when cold air moves over a warm surface.

How does moderate turbulence affect an aircraft?

Changes in altitude or attitude occur but the aircraft remains in positive control at all times.

Conditions favorable for low-level frictional turbulence are

strong wind, rough terrain, and steep lapse rate.

Possible severe turbulence will be encountered in mountain waves

in the rotor clouds.

The primary ingredients required for thunderstorm formation are

a high moisture content, a steep lapse rate, and a lifting agent.

During which stage of thunderstorm formation does the updraft hold all the water droplets and ice crystals preventing precipitation from falling?

Cumulus stage

Squall lines are long bands of thunderstorm activity that typically form

ahead of a cold front.

Downdrafts dominate the thunderstorm during the

dissipating stage.

During thunderstorm formation precipitation falls during the

mature stage.

Lightning poses the greatest danger to an aircraft when

temperature at operating altitude is between -5°C and 5°C.

A waterspout is

a funnel cloud that makes contact with a body of water.

The best description for the formation of hail?

Updrafts carry precipitation above the freezing level freezing the droplets.

It is not correct regarding thunderstorms that
Select one:

a. thunderstorms are difficult to asses the severity of by visual observation alone.

b. the turbulence associated with a storm may extend up to 20 NM away.

c. the turbulence below thunderstorms should not be underestimated.

d. the severity of most storms are short lived so little precaution need be taken for most aircraft.

Question is asking NOT correct.

The correct answer is: the severity of most storms are short lived so little precaution need be taken for most aircraft.

When a thunderstorm is directly ahead en route to the destination

maintaining 20 NM from the storm is the best choice.

If flight through a thunderstorm cannot be avoided, minimize critical icing encounters by

flying at an altitude that is lower than the freezing level

and

planning a course that will take the aircraft through the storm in the shortest time.

It is not correct regarding thunderstorm penetration that

Select one:

a. cockpit lights should be turned ON to their highest intensity.

b. maintain a constant power setting.

c. to reduce the time spent in the storm maximum cruise speed should be chosen.

d. pitot and carburetor heat should be turned ON.

Question is asking NOT correct.

The correct answer is: to reduce the time spent in the storm maximum cruise speed should be chosen.

Question text

Which factor will not cause the formation of thunderstorms?

Select one:

a. A warm front

b. An occlusion

c. A cold front

d. Sea fog

Sea Fog

The stages of thunderstorm development are the

Cumulus, mature and dissipating.

The fastest moving thunderstorms are

frontal type

The formation of a cumulonimbus (CB) depends on

• some sort of lifting of the air.

• instability of thick layers of air.

• warm and humid air.

The highest frequency of thunderstorms encountered are in

tropical regions

What is a squall line?

A band of intense thunderstorms.

Thunderstorms reach their greatest intensity during the

mature stage

The initial phase of a thunderstorm is characterized by

continuous updrafts

It is correct with regard to a mature thunderstorm that

both updrafts and downdrafts appear concurrently.

In a thunderstorm pilots should be on alert for hail when radar echoes

are well defined

Aircraft struck by lightning may sometimes get considerable damage and at least temporarily the maneuvering of the aircraft will be made more difficult. It is correct that an aircraft

Metal conducts lightning energy and discharges it again with potentially less damage. But some composite material is not a good conductor by nature. Thus, lightning energy can do considerable damage before it is discharged, unless special design features ensure proper discharge.

The question is talking about operations of the aircraft. If the aircraft is damaged it will have to be operated in a manor that will not create more damage. If a crew member has flash blindness (can't read the instruments or look for other aircraft) or lost their hearing (not able to hear radio calls) then they will not be able to perform their duties.

The correct answer is: made by composite material may get severe damage, the crew may be blinded, and may temporarily lose their hearing.

In a tornado the path of destruction can reach . . . . . and wind speeds of . . . . . have been recorded.

2 to 2.5 miles, 280 MPH

During what time of the year are tornadoes most likely to occur in North America?

Spring and Summer

Frontal fog occurs when very

humid warm air meets with very humid cold air.

Frontal fog is most likely to occur in

advance of a warm front

Advection fog is likely to form when

warm moist air over cold surface.

At what time of day or night is radiation fog least likely to occur?

In the afternoon

Radiation fog usually clears with

The sun evaporates radiation fog, stronger winds mix saturated air with unsaturated air, reducing the humidity. (refer diagram in slide)

The correct answer is: strong winds and daytime heating.

What are the differences between radiation fog and advection fog?

Radiation fog forms due to surface cooling at night in a light wind and advection fog forms when warm humid air flows over a cold surface.

If low cloud reduces visibility to less than 5/8 SM it is referred to as

fog

Steam fog forms when

cold dry air blows over warm water.

When warm moist air travels across a cool surface forms

advection fog

High humidity and clear skies with light winds can produce

radiation fog

Fog can be anticipated when the

temperature and dew point spread is small and decreasing.

Which is not a requirement for the formation of fog?

Select one:

a. Condensation nuclei

b. A cooling process

c. Moderate surface winds

d. High humidity

Question is asking NOT required.

The question is asking about all fog formation. Out of all the types of fog none form cause of moderate or stronger winds. Any wind that can cause mechanical turbulence will mix the air enough to break up fog.
A cooling process is one of the main ways to form fog and clouds. One reason why METARS give a dew point. This shows how much or how little cooling is needed to have the moisture in the air to start to coming out.
The higher the humidity in the air the closer to the point (dew point) where the air can not hold all that moisture—so the moisture comes out as fog or clouds.

The correct answer is: Moderate surface winds

What are the main types of airframe icing?

clear ice, rime ice, mixed ice

How does airframe ice form?

It is possible for liquid water drops to exist in the atmosphere at temperatures well below the normal freezing point of water. These are known as super-cooled drops.When they contact a surface colder than freezing point, they will freeze.

The correct answer is: Super-cooled water droplets strike a cold airframe.

In what temperature range is the risk of airframe icing most severe in convective cloud?

0 degrees Celsius - minus 10 degrees Celsius.

In what cloud type is the risk of severe clear airframe icing present?

Cumulus, temperature 0 degrees Celsius - minus 10 degrees Celsius.

What effect does airframe icing have on aircraft performance?

This will cause an increase in stall speed. Stall can occur long before the stall warning system activates.

The correct answer is: It will disrupt the laminar airflow over the airfoils.

With respect to airframe icing, which of the following is true? Airframe icing causes:

Stalling speed to increase due to the disruption caused to the laminar flow of air on the airfoils.

What effect does icing have on aircraft propellers?

Uneven shedding of ice can cause destructive vibrations.

With regards to airframe icing catch rate, which of the following is true?

A. Airframe icing catch rate is not important, and is irrelevant to the dangers associated with icing.

B. A thick wing has a greater catch rate than a thin wing.

C. The design of a wing is not a factor that affects the catch rate.

D. A thin wing has a greater catch rate than a thick wing.

A thin wing has a greater catch rate than a thick wing

With regards to airframe icing catch rate, which of the following is true?

The slower the aircraft, the lower the catch rate.

With respect to frost adhering to an airfoil, which of the following is true?

Select one:

A. An amount of frost, consistent with that of coarse sandpaper, adhering to the critical surfaces, can increase drag by 40%, and decrease lift by 30%.

B. Frost has no adverse effect on the airfoil, but may turn into ice during the takeoff roll.

C. Frost does not have any adverse effects on the airfoil.

D. An amount of frost, consistent with that of coarse sandpaper, adhering to the critical surface, can increase drag by 30%, and decrease lift by 40%.

An amount of frost, consistent with that of coarse sandpaper, adhering to the critical surfaces, can increase drag by 40%, and decrease lift by 30%.

How should you recover from a tail stall?

Raise flaps to previous setting; pull back on yoke; reduce power.

Hoar frost forms on an aircraft when its surfaces are __________ freezing and the surrounding air is warmer but below freezing and _________.

Below, moist

Because hoar frost forms by deposition, we can say that hoar frost forms in:

Clean Air

Clear ice is formed in:

Freezing rain.

Rime ice is formed in:

stratiform clouds

Which type of icing would anti-icing/de-icing equipment be more effective on?

Rime

Large super-cooled water droplets require:

Require strong vertical currents to support them, therefore they are most commonly found in cumulus cloud.

Clear ice is formed in:

cumulous clouds

The most serious icing is found in:

cumulus clouds

To reduce the icing intensity while in cumulus cloud:

Avoid altitudes where the temperature is between 0º and -10º Celcius.