What is a roll upset?

A roll upset is defined as a situation where airflow separation leads to unintended aileron deflection, resulting in an unwanted roll motion of the aircraft. This phenomenon usually occurs under specific conditions, such as during high angles of attack or in turbulent air, where the airflow over the wings becomes disrupted. When airflow separates from the wing, it can affect the control surfaces, particularly the ailerons, causing them to deflect in a manner that does not correspond to pilot input.

This can result in significant challenges for pilots, especially in maintaining control of the aircraft. Understanding roll upsets is crucial for flight instructors, as they need to train students on how to prevent and recover from such situations effectively. The other choices describe different flight phenomena but do not accurately capture the mechanics and consequences of a roll upset.