Plain English Meaning

When ATC can't see you on radar, you tell them where you are by voice as you cross certain points along your route, so they can keep track of your flight.

Full Definition

Verbal reports made by a pilot to ATC over specified compulsory reporting points when operating in airspace where radar coverage is unavailable. Each report includes aircraft identification, position, time, altitude, type of flight plan, ETA and name of the next reporting point, the name of the reporting point following that, and any pertinent remarks. These reports allow ATC to maintain and track the flight without radar.