Hovering: helicopters holding still in the air

Helicopters can stay in one place in the air, which almost no other aircraft can do. Medical, police, news and utility crews hover to work on the ground below, and pilots practice it as a basic skill. In the data a hover shows up as a helicopter whose ground speed falls to almost nothing while its position stays put.

The site looks for a rotorcraft reporting a ground speed of 8 knots or less over a short stretch while its altitude changes by less than 200 ft. A helicopter sitting on a pad with its transponder on can report the same thing, so the hover must have forward flight before and after it in the same stretch of track, or a clear climb or descent. Without that evidence the story is held back, and so is a hover longer than ten minutes, because a long stop on a pad and a real hover can look alike.

A hover marks where a helicopter stopped. The data cannot show what its crew was doing there, whether a rescue, a patrol or a news shot, and a low hover over a field can be a landing that the records missed. Positions from multilateration are estimates with a wider margin of error, so a hover built from them is never published.