Certified Flight Instructor - Flight Instructor Airplane Practice Exam

What is one of the most dangerous features of mountain waves?

1. turbulence at ground level

2. turbulent areas below rotor clouds

3. wind shear in flat terrain

4. low visibility in the valleys

The correct answer is: turbulent areas below rotor clouds

Mountain waves are a phenomenon that occurs when strong winds blow over mountain ranges, creating turbulent airflow. One of the most dangerous features associated with mountain waves is the turbulent areas that develop below rotor clouds. This occurs when the airflow is disturbed by the mountains, resulting in the formation of turbulent eddies, particularly beneath the rotor, which can extend for several miles downwind of the mountains. Rotor clouds signify a significant turbulence area and can produce extreme and potentially hazardous conditions for pilots flying in or near mountainous terrain. These turbulent areas are characterized by rapid changes in wind direction and speed, which can lead to difficulties in control, especially for smaller aircraft. This is crucial for pilots to understand as encountering such turbulence can lead to loss of control or even structural failure of an aircraft. While turbulence at ground level, wind shear in flat terrain, and low visibility in valleys can pose risks as well, they are not specifically linked to the dangerous nature of mountain waves in the same way that turbulent areas below rotor clouds are. The unique and severe turbulence associated with mountain waves, particularly beneath rotor structures, highlights why this feature is recognized as especially dangerous.