If aircraft attitudes change abruptly during turbulence, which category of turbulence are they likely experiencing?

The correct answer is severe turbulence. Severe turbulence is characterized by large, abrupt changes in altitude and/or attitude of the aircraft. This level of turbulence can cause significant discomfort to passengers and crew, as well as a challenging situation for pilots who need to maintain control. During severe turbulence, aircraft may experience violent updrafts or downdrafts that can lead to drastic changes in flight path and attitude.

In contrast, chop refers to mild, short-duration disturbances that cause minor changes in altitude or attitude but do not result in the extensive movements associated with severe turbulence. Extreme turbulence, while also involving dramatic changes, is even more intense than severe turbulence and is less commonly encountered. Light turbulence typically involves slight, smooth changes and does not present any major control issues for pilots. Thus, when aircraft attitudes change abruptly, it is indicative of severe turbulence effects.