What is a necessary action if you encounter turbulence while flying?

When encountering turbulence while flying, reporting it to Air Traffic Control (ATC) is a necessary action for several reasons. Firstly, communication of turbulence conditions helps ATC to provide updated information to other pilots in the area, which enhances overall safety. Such reports allow ATC to modify flight paths or provide warnings to other aircraft that may be approaching the turbulent area, thereby mitigating the risks associated with unexpected turbulence.

Additionally, reporting turbulence contributes to the collective knowledge and understanding of air traffic conditions. It helps in building a database of turbulence occurrences which can be invaluable for future flights and operations.

While mild turbulence might not seem like an immediate concern, communicating even minor encounters ensures that you are following protocol and keeping everyone informed. Changing your course or altitude without assessing the situation further might not be safe or necessary and could lead to complicated airspace management issues. Thus, the appropriate and responsible action in the case of encountering turbulence is to notify ATC.