FAA Ground School Practice Test

Which condition is associated with smooth air and poor visibility?

1. High altitude turbulence

2. Temperature inversions with high humidity

3. Cold fronts moving through

4. Warm fronts retreating quickly

The correct answer is: Temperature inversions with high humidity

The condition associated with smooth air and poor visibility is temperature inversions with high humidity. During a temperature inversion, a layer of warm air traps cooler air beneath it, which can lead to a stable atmosphere with little vertical movement. This stability often results in smooth air and can inhibit the dispersion of pollutants, moisture, and fog, thus contributing to poor visibility. In high humidity situations, the moisture in the air can condense and contribute to the formation of clouds or reduce visibility due to haze. Together, these factors create an environment that is characterized by calm conditions, yet that same calmness can be deceiving as it often comes with the downside of limited visibility. The other options, while they may have some impact on flying conditions, do not specifically relate to the combination of smooth air and reduced visibility in the same way temperature inversions do. High altitude turbulence tends to be associated with increased wind activity and unstable air, cold fronts typically bring about turbulent weather conditions, and warm fronts often lead to cloudiness but not necessarily smooth air combined with poor visibility like that found in temperature inversions.