Glossary
What is VFR flight following?
A service in which air traffic control watches a VFR flight on radar and calls out traffic that may become a factor. It is requested rather than required, is provided only when controller workload allows, and it never removes the pilot's own duty to see and avoid.
Also called Radar traffic advisories
That is the whole entry for now. The longer version, with the mechanics and worked examples, is still to be written. See autorotation for how those read once they exist.