FAA Aircraft Dispatcher Practice Exam

What is clear air turbulence (CAT)?

1. Turbulent movement of air caused by ground obstacles

2. A smooth airflow with no turbulence

3. Turbulent movement of air masses in the absence of visual cues

4. A weather phenomenon that occurs only at night

The correct answer is: Turbulent movement of air masses in the absence of visual cues

Clear air turbulence (CAT) refers to the turbulent movement of air masses that occurs in clear air, typically at high altitudes, and without any visual cues to indicate its presence. This type of turbulence is particularly challenging because it often occurs away from thunderstorms and is not associated with any visible weather patterns such as clouds or precipitation. Pilots might find themselves entering CAT unexpectedly, leading to sudden changes in altitude and direction. The distinguishing factor of CAT is its occurrence in seemingly tranquil conditions, which can catch both pilots and passengers off guard. Since it happens in clear air, it lacks the visual indicators such as clouds that usually help in predicting turbulence, making it essential for pilots to rely on instruments and reports from other aircraft to navigate safely. In contrast, the options that describe turbulence caused by ground obstacles would typically relate to mechanical turbulence rather than clear air phenomena. A smooth airflow without turbulence is contrary to the definition of clear air turbulence, as CAT implies the presence of turbulent movements. Lastly, suggesting that CAT occurs only at night limits the phenomenon to a specific time, whereas it can occur at any time, day or night, regardless of visibility conditions.