Drone Pilot Practice Exam

What condition leads to a stall in an unmanned aircraft?

1. The wing exceeds its critical angle of attack

2. The engine power is too low

3. The aircraft is overloaded

4. The control surfaces are unresponsive

The correct answer is: The wing exceeds its critical angle of attack

A stall in an unmanned aircraft occurs when the wing exceeds its critical angle of attack. The critical angle of attack is the maximum angle at which air can flow over the wing without separating from the surface. When this angle is exceeded, the smooth airflow over the wing is disrupted, leading to a significant loss of lift. This condition can occur regardless of airspeed, and it is primarily dependent on the angle between the wing and the oncoming air. While engine power, aircraft loading, and control surface responsiveness are all important factors in flight operations, none directly cause a stall in the same manner that exceeding the critical angle of attack does. Engine power being too low can lead to other issues, but it does not necessarily result in a stall by itself. Similarly, an overloaded aircraft may have performance limitations, but a stall is specifically related to the wing's angle of attack. Unresponsive control surfaces can complicate recovery from a stall but do not initiate the stall condition itself. Therefore, understanding the relationship between angle of attack and stall conditions is critical for safe unmanned aircraft operation.