Drone Pilot Practice Exam

Which of the following conditions is most likely associated with high density altitude?

1. Clear sky with wind

2. Hot and humid weather

3. Cool and dry weather

4. Thunderstorm activity

The correct answer is: Hot and humid weather

High density altitude occurs when the air is less dense, which can significantly impact aircraft performance, including lift, engine efficiency, and propeller effectiveness. The most common cause of high density altitude is a combination of high temperatures and humidity. When the temperature increases, the air molecules are spaced farther apart, which decreases the density of the air. Similarly, high humidity means that there are more water vapor molecules in the air, which are lighter than the nitrogen and oxygen molecules they displace, further reducing air density. In situations of hot and humid weather, the combination of high temperature and elevated moisture content in the air makes this condition particularly pronounced. Pilots must be aware of high density altitudes since they increase the required distance for takeoff and landing and can affect the aircraft’s overall performance. In contrast, conditions associated with clear skies and wind, cool and dry weather, or thunderstorm activity do not typically result in high density altitudes like hot and humid weather does. Cool, dry weather generally leads to lower density altitudes since colder air is denser.