12 free practice questions from the 259 in this chapter of StudyWren Aviation. Pick an answer and check it to see the explanation and its FAA source. Part of the free Private Pilot practice test.
AtmospherePAR-08-002
In which layer of the atmosphere does nearly all weather occur?
Choose an answer first.
Correct
The answer is C: Troposphere
The troposphere extends from the surface to the tropopause and contains almost all of the atmosphere's water vapor, so clouds, precipitation, and most weather form there. The stratosphere above is very dry and has little weather.
The troposphere extends from the surface to the tropopause and contains almost all of the atmosphere's water vapor, so clouds, precipitation, and most weather form there. The stratosphere above is very dry and has little weather.
How does the strength of the Coriolis force vary with latitude?
Choose an answer first.
Correct
The answer is A: It is zero at the equator and greatest at the poles
The Coriolis effect increases with latitude, from zero at the equator to a maximum at the poles, and it also increases with wind speed. This is why large rotating storm systems do not form right at the equator.
The answer is A: It is zero at the equator and greatest at the poles
The Coriolis effect increases with latitude, from zero at the equator to a maximum at the poles, and it also increases with wind speed. This is why large rotating storm systems do not form right at the equator.
In winter, the temperature at an airport just east of the Rocky Mountains rises sharply within an hour as a gusty westerly wind descends the slopes. What is this wind?
Choose an answer first.
Correct
The answer is B: A Chinook (foehn) wind
Air that lost moisture on the windward side descends the lee slope and warms by compression at the dry adiabatic rate, arriving warm and dry. Chinooks can raise lee-side temperatures sharply in a short time and are often gusty and turbulent. A valley breeze flows upslope, not down.
Air that lost moisture on the windward side descends the lee slope and warms by compression at the dry adiabatic rate, arriving warm and dry. Chinooks can raise lee-side temperatures sharply in a short time and are often gusty and turbulent. A valley breeze flows upslope, not down.
An airplane is parked outside on a clear, calm night. Under what condition will frost form on its wings?
Choose an answer first.
Correct
The answer is B: The wing surface cools to the dewpoint, which is below freezing
Frost forms by deposition: water vapor changes directly to ice on a surface that has cooled to a dewpoint that is below freezing. Rain freezing on contact produces glaze (clear) ice, not frost.
The answer is B: The wing surface cools to the dewpoint, which is below freezing
Frost forms by deposition: water vapor changes directly to ice on a surface that has cooled to a dewpoint that is below freezing. Rain freezing on contact produces glaze (clear) ice, not frost.
When an entire layer of air is lifted and stretched vertically, how does its stability tend to change?
Choose an answer first.
Correct
The answer is C: Its stability decreases
As a layer is lifted and stretched, its top cools more than its bottom, steepening the lapse rate and decreasing stability. Sinking (subsidence) does the opposite and increases stability.
As a layer is lifted and stretched, its top cools more than its bottom, steepening the lapse rate and decreasing stability. Sinking (subsidence) does the opposite and increases stability.
Before a summer cross-country, you see altocumulus castellanus (turret-shaped clouds at middle levels) in the morning sky. What do they indicate?
Choose an answer first.
Correct
The answer is C: Instability at middle levels that favors later convection
PHAK describes castellanus as clouds with a common base and separate, castle-like vertical development, and the Aviation Weather Handbook lists altocumulus among the visible forms of convection. Turrets at middle levels therefore show unstable air aloft, an early sign that convection, including thunderstorms, may build as the day warms.
The answer is C: Instability at middle levels that favors later convection
PHAK describes castellanus as clouds with a common base and separate, castle-like vertical development, and the Aviation Weather Handbook lists altocumulus among the visible forms of convection. Turrets at middle levels therefore show unstable air aloft, an early sign that convection, including thunderstorms, may build as the day warms.
While climbing in cloud, you begin encountering freezing rain. What does this indicate about the air above you?
Choose an answer first.
Correct
The answer is C: A layer of above-freezing air exists at a higher altitude
Freezing rain begins as rain (or melted snow) in a warmer layer aloft and becomes supercooled as it falls into below-freezing air. Its presence means there is a temperature inversion with above-freezing air higher up.
The answer is C: A layer of above-freezing air exists at a higher altitude
Freezing rain begins as rain (or melted snow) in a warmer layer aloft and becomes supercooled as it falls into below-freezing air. Its presence means there is a temperature inversion with above-freezing air higher up.
In an air-mass label the lowercase letter shows the moisture source (c = continental, dry; m = maritime, moist) and the capital letter the temperature source (P = polar, cold). cP air forms over cold northern land such as Canada, so it is cold and dry.
In an air-mass label the lowercase letter shows the moisture source (c = continental, dry; m = maritime, moist) and the capital letter the temperature source (P = polar, cold). cP air forms over cold northern land such as Canada, so it is cold and dry.
You are watching a large cumulus cloud build near your route. Which observation signals that it has entered the mature stage?
Choose an answer first.
Correct
The answer is A: Precipitation starts reaching the ground from the cloud
The mature stage begins when precipitation falls out of the cloud base and reaches the surface, dragging air down into strong downdrafts alongside the remaining updrafts. Downdrafts throughout the cell indicate the dissipating stage.
The answer is A: Precipitation starts reaching the ground from the cloud
The mature stage begins when precipitation falls out of the cloud base and reaches the surface, dragging air down into strong downdrafts alongside the remaining updrafts. Downdrafts throughout the cell indicate the dissipating stage.
Relative to the jet stream core, where is clear air turbulence most frequently encountered?
Choose an answer first.
Correct
The answer is C: On the polar (low-pressure) side, especially near upper troughs
The strongest wind shear, and therefore CAT, tends to occur on the cold, low-pressure side of the jet core and where the jet curves sharply around deep upper troughs.
The answer is C: On the polar (low-pressure) side, especially near upper troughs
The strongest wind shear, and therefore CAT, tends to occur on the cold, low-pressure side of the jet core and where the jet curves sharply around deep upper troughs.
You are flying VFR up a mountain valley toward a pass. Clouds are lowering over the ridges, and light precipitation is falling ahead. What hazard is developing?
Choose an answer first.
Correct
The answer is A: Mountain obscuration, with terrain hidden in cloud ahead
Low clouds and precipitation can hide ridges and passes, leaving no room to turn around in a narrowing valley. Mountain obscuration is a major cause of VFR flight into terrain; turn back early while visual references remain.
The answer is A: Mountain obscuration, with terrain hidden in cloud ahead
Low clouds and precipitation can hide ridges and passes, leaving no room to turn around in a narrowing valley. Mountain obscuration is a major cause of VFR flight into terrain; turn back early while visual references remain.
