6. Weather and Micrometeorology Flashcards
What is the standard air temperature and pressure at sea level?
A) 15º C 29.92” Hg
B) 59º C 1013 millibars
C) 17º C 1013 millibars
A) 15º C 29.92” Hg
What effect does high density altitude have on the efficiency of a UA propeller?
A) Propeller efficiency is increased.
B) Propeller efficiency is decreased.
C) Density altitude does not affect propeller efficiency.
B) Propeller efficiency is decreased.
What is true altitude?
A) The height above the surface.
B) The vertical distance of the aircraft above the surface.
C) The vertical distance of the aircraft above sea level.
C) The vertical distance of the aircraft above sea level.
Which combination of atmospheric conditions will reduce aircraft takeoff and climb performance?
A) Low temperature, low relative humidity, and low density altitude.
B) High temperature, low relative humidity, and low density altitude.
C) High temperature, high relative humidity, and high density altitude.
C) High temperature, high relative humidity, and high density altitude.
If the outside air temperature (OAT) at a given altitude is warmer than standard, the density altitude is
A) lower than pressure altitude.
B) higher than pressure altitude.
C) equal to pressure altitude.
B) higher than pressure altitude.
Density altitude is defined by
A) humidity and braking friction forces.
B) headwind and landing weight.
C) pressure altitude and ambient temperature.
C) pressure altitude and ambient temperature.
What effect, if any, does high humidity have on sUAS performance?
A) It increases performance.
B) It decreases performance.
C) It has no effect on performance.
B) It decreases performance.
Which factor would likely increase density altitude?
A) An increase in ambient temperature.
B) A decrease in relative humidity
C) An increase in barometric pressure.
A) An increase in ambient temperature.
When is pressure altitude equal to density altitude?
A) When the temperature and dew point are beginning to converge
B) When advection fog is present
C) On a standard day (15º C and 29.92” Hg)
C) On a standard day (15º C and 29.92” Hg)
How would high density altitude affect the performance of a small unmanned aircraft?
A) Increased performance
B) Decreased performance
C) No change in performance
B) Decreased performance
6.2
You’re operating a fixed-wing UA over barren ground on a hot day at low-altitude. You can expect to encounter
A) good visibility.
B) bumpy, turbulent air.
C) smooth, moist air.
B) bumpy, turbulent air.
The change in wind speed and direction over a short distance is known as
A) temperature inversion.
B) wind shear.
C) wind vortex.
B) wind shear.
There are many considerations when looking at wind. Which of the following is generally not a concern:
A) Wind shear
B) Tide pools
C) Local wind
B) Tide pools
Where does wind shear occur?
A) Only at higher altitudes
B) Only at lower altitudes
C) At all altitudes
C) At all altitudes
When may hazardous wind shear be expected?
A) When moist, unstable air crosses a mountain barrier
B) Following frontal passage when cumulus clouds form
C) In areas of low-level temperature inversion, frontal zones, and clear air turbulence
C) In areas of low-level temperature inversion, frontal zones, and clear air turbulence
While operating around buildings, the Remote PIC should be aware of the creation of wind gusts that:
A) Enhance stability and imagery
B) Change rapidly in direction and speed causing turbulence
C) Increase performance of the aircraft
B) Change rapidly in direction and speed causing turbulence
You have received an outlook briefing from flight service through 1800wxbrief.com. The briefing indicates you can expect a low-level temperature inversion with high relative humidity. What weather conditions would you expect?
A) Smooth air, poor visibility, fog, haze, or low clouds.
B) Light wind shear, poor visibility, haze, and light rain.
C) Turbulent air, poor visibility, fog, low stratus type clouds, and showery precipitation.
A) Smooth air, poor visibility, fog, haze, or low clouds.
6.3
Moisture is added to air by
A) sublimation and condensation.
B) evaporation and condensation.
C) evaporation and sublimation.
C) evaporation and sublimation.
Why is frost considered hazardous to sUAS operations?
A) Frost decreases lift capacity by changing the aerodynamic shape of the propellers.
B) Frost decreases lift capacity by spoiling the smooth flow of air over the propellers.
C) Frost increases control effectiveness by slowing the airflow.
B) Frost decreases lift capacity by spoiling the smooth flow of air over the propellers.
If the temperature is 64°F (and if the temperature/dewpoint spread is too small and decreasing), what type of weather is most likely to develop?
A) Fog or low clouds
B) Freezing precipitation
C) Thunderstorms
A) Fog or low clouds
What is “dewpoint”?
A) The temperature at which condensation and evaporation are equal.
B) The temperature at which dew will always form.
C) The temperature to which air must be cooled to become saturated.
C) The temperature to which air must be cooled to become saturated.
The amount of water vapor which air can hold depends on the
A) air temperature.
B) dewpoint.
C) stability of the air.
A) air temperature.
Clouds, fog, or dew will always form when
A) relative humidity reaches 100 percent.
B) water vapor condenses.
C) water vapor is present.
B) water vapor condenses.
Low-level turbulence can occur (and icing can become hazardous) in which type of fog?
A) Rain-induced fog
B) Steam fog
C) Upslope fog
B) Steam fog
Advection fog will most likely form when
A) an air mass moves inland from the coast.
B) a light breeze blows colder air out to sea.
C) there’s a warm, moist air mass on the windward side of mountains.
A) an air mass moves inland from the coast.
Radiation fog will most likely form when
A) there is warm, moist air over low, flatland areas on clear, calm nights.
B) moist, tropical air moves over cold, offshore water.
C) cold air moves over much warmer water.
A) there is warm, moist air over low, flatland areas on clear, calm nights.
Frost is most likely to form on a UAV’s wings or propellers:
A) when the temperature of the wing or propeller’s surface is below the dew point of the surrounding air
B) when the dewpoint is lower than 0° C.
C) when the temperature of the wing or propeller’s surface is below the dew point of the surrounding air AND the dew point is lower than 0° C.
C) when the temperature of the wing or propeller’s surface is below the dew point of the surrounding air AND the dew point is lower than 0° C.
The temperature and dew point are each forecasted to be 10°C. What weather should you expect?
A) Strong wind
B) Freezing rain
C) Fog or low clouds
C) Fog or low clouds
6.4
In a METAR report, what does “BR” indicate?
A) Broken clouds
B) Mist
C) Brown
B) Mist