Free FAA-107 Effects of Weather on sUAS Performance Questions and Answers — Questions and Answers
Question 1: What effect does high density altitude have on the performance of a small unmanned aircraft?
- Performance is increased due to less air resistance.
- Performance is decreased due to reduced propeller efficiency. (Correct answer)
- Performance is not affected by density altitude.
- Performance is only affected by the aircraft's weight.
Correct answer: Performance is decreased due to reduced propeller efficiency.
High density altitude means the air is less dense. This reduces propeller efficiency, decreases lift, and diminishes engine power output, all of which lead to reduced overall performance.
Question 2: Which combination of conditions would lead to the highest density altitude?
- High altitude, high temperature, and high humidity. (Correct answer)
- Low altitude, low temperature, and low humidity.
- High altitude, low temperature, and low humidity.
- Low altitude, high temperature, and low humidity.
Correct answer: High altitude, high temperature, and high humidity.
Density altitude increases with higher elevation, higher temperatures, and higher humidity. Therefore, a hot, humid day at a high-elevation airport will produce the highest density altitude and the worst aircraft performance.
Question 3: What are the characteristics of a stable air mass?
- Turbulent air, good visibility, and cumuliform clouds.
- Showery precipitation, strong surface winds, and good visibility.
- Smooth air, poor visibility, and stratiform clouds. (Correct answer)
- Thunderstorms, turbulence, and hail.
Correct answer: Smooth air, poor visibility, and stratiform clouds.
In a stable air mass, vertical air movement is resisted. This results in smooth air, poor visibility due to trapped haze and pollutants, and stratiform clouds with steady, continuous precipitation.
Question 4: A temperature inversion can create a hazard for sUAS operations primarily because it can lead to:
- Increased air density and better performance.
- Significant wind shear and poor visibility. (Correct answer)
- The rapid formation of cumulonimbus clouds.
- Decreased propeller efficiency regardless of altitude.
Correct answer: Significant wind shear and poor visibility.
A temperature inversion creates a very stable layer of air that can trap smoke, dust, and other pollutants, leading to very poor visibility. It can also be a source of significant low-level wind shear.
Question 5: When flying an sUAS, structural icing is most likely to form when:
- The temperature is below freezing and the air is dry.
- Flying through visible moisture at temperatures at or below freezing. (Correct answer)
- The relative humidity is 100%, regardless of temperature.
- Flying at any altitude above the freezing level.
Correct answer: Flying through visible moisture at temperatures at or below freezing.
For structural ice to form, two conditions must be met: the aircraft must be flying through visible moisture (like clouds or freezing rain), and the temperature of the aircraft surface must be at or below freezing (0°C).
Question 6: What is the primary danger associated with thunderstorms for an sUAS?
- Radio frequency interference.
- Low ceilings and poor visibility.
- Extreme turbulence and wind shear. (Correct answer)
- High density altitude.
Correct answer: Extreme turbulence and wind shear.
While all listed options are hazards, the most significant and immediate danger from thunderstorms is the extreme turbulence and wind shear associated with updrafts, downdrafts (microbursts), and gust fronts. These can easily cause a loss of control.
Free FAA-107 Effects of Weather on sUAS Performance Questions and Answers
What effect does high density altitude have on the performance of a small unmanned aircraft?