ASA Private Pilot 2020 Test Prep (Chapter 6)

At approximately what altitude above the surface would the pilot expect the base of cumuliform clouds if the surface air temperature is 82 degrees F and the dewpoint is 38 degrees F?

10,000 feet AGL

A pilot can expect a wind-shear zone in a temperature inversion whenever the windspeed at 2,000 to 4,000 feet above the surface is at least

25 knots

What is the approximate base of the cumulus clouds if the surface air temperature at 1,000 feet MSL is 70 degrees F and the dewpoint is 48 degrees F?

6,000 feet MSL

What feature is associated with a temperature inversion?

A stable layer of air

What measurement can be used to determine the stability of the atmosphere?

Actual lapse rate

What types of fog depend upon wind in order to exist?

Advection fog and upslope fog

In which situation is advection fog most likely to form?

An air mass moving inland from the coast in winter

Where does wind shear occur?

At all altitudes, in all directions.

What are characteristics of a moist, unstable air mass?

Cumuliform clouds and showery precipitation

What clouds have the greatest turbulence?

Cumulonimbus

During the life cycle of a thunderstorm, which stage is characterized predominately by downdrafts?

Dissipating

What are the processes by which moisture is added to unsaturated air?

Evaporation and sublimation

If the temperature/dewpoint spread is small and decreasing, and the temperature is 62 degrees F, what type of weather is most likely developing

Fog or low clouds

Why is frost considered hazardous to flight?

Frost spoils the smooth flow of air over the wings, thereby decreasing lifting capability

How will frost on the wings of an airplane affect takeoff performance?

Frost will disrupt the smooth flow of air over the wing, adversely affecting its lifting capability

What conditions are necessary for the formation of thunderstorms?

High humidity, lifting force, and unstable conditions

When may hazardous wind shear be expected?

In areas of low-level temperature inversion, frontal zones, and clear air turbulence

Upon encountering severe turbulence, which flight condition should the pilot attempt to maintain?

Level flight attitude

Which weather phenomenon is always associated with a thunderstorm?

Lightning

A stable air mass is most likely to have which characteristic?

Poor surface visibility

Which weather phenomenon signals the beginning of the mature stage of a thunderstorm?

Precipitation beginning to fall

Which weather conditions should be expected beneath a low-level temperature inversion layer when the relative humidity is high?

Smooth air, poor visibility, fog, haze, or low clouds

Low-level turbulence can occur and icing can become hazardous in which type of fog?

Steam fog

What is a characteristic of stable air?

Stratiform clouds

Which conditions result in the formation of frost?

The temperature of the collecting surface is at or below the dewpoint of the adjacent air and the dewpoint is below freezing

What cloud types would indicate convective turbulence?

Towering cumulus clouds

What are characteristics of unstable air?

Turbulence and good surface visibility.

What causes variations in altimeter settings between weather reporting points?

Unequal heating of the Earth's surface

What would decrease the stability of an air mass?

Warming from below

One of the most easily recognized discontinuities across a front is

a change in temperature

An almond or lens-shaped cloud which appears stationary, but which may contain winds of 50 knots or more, is referred to as

a lenticular cloud

The suffix "nimbus", used in naming clouds means

a rain cloud

Possible mountain wave turbulence could be anticipated when winds of 40 knots or greater blow

across a mountain ridge, and the air is stable

When there is a temperature inversion, you would expect to experience

an increase in temperature as altitude increases

If an unstable air mass is forced upward, what type clouds can be expected?

clouds with considerable vertical development and associated turbulence

What feature is normally associated with the cumulus stage of a thunderstorm?

continuous updraft

Convective circulation patterns associated with sea breezes are caused by

cool, dense air moving inland from over the water

In which environment is aircraft structural ice most likely to have the highest accumulation rate?

freezing rain

The wind at 5,000 feet AGL is southwesterly while the surface wind is southerly. This difference in direction is primarily due to

friction between the wind and the surface

Every physical process of weather is accompanied by, or is the result of, a

heat exchange

Clouds are divided into four families according to their

height range

The presence of ice pellets at the surface is evidence that there

is a temperature inversion with freezing rain at a higher altitude

Thunderstorms reach their greatest intensity during the

mature stage

When warm, moist, stable air flows upslope, it

produces stratus type clouds

A nonfrontal, narrow band of active thunderstorms that often develop ahead of a cold front is known as a

squall line

Thunderstorms which generally produce the most intense hazard to aircraft are

squall line thunderstorms

Crests of standing mountain waves may be marked by stationary, lens-shaped clouds known as

standing lenticular clouds

Steady precipitation preceding a front is an indication of

stratiform clouds with little or no turbulence

The most frequent type of ground or surface-based temperature inversion is that which is produced by

terrestrial radiation on a clear, relatively still night

The mature stage of a thunderstorm begins with

the start of precipitation

The conditions necessary for the formation of cumulonimbus clouds are a lifting action and

unstable, moist air

During a cross-country flight you picked up rime icing which you estimate is 1/2 inches thick on the leading edge of the wings. You are now below the clouds at 2,000 feet AGL and are approaching your destination airport under VFR. Visibility under the clouds is more than 10 miles, winds at the destination airport are 8 knots right down the runway, and the surface temperature is 3 degrees C. You decide to:

use a faster than normal approach and landing speed

One in-flight condition necessary for structural icing to form is

visible moisture

What situation is most conducive to the formation of radiation fog?

warm, moist air over low, flatland areas on clear, calm nights

One weather phenomenon which will always occur when flying across a front is a change in the

wind direction

If there is thunderstorm activity in the vicinity of an airport at which you plan to land, which hazardous atmospheric phenomenon might be expected on the landing approach?

wind-sheer turbulence