(ATC) Air Traffic Control separates IFR aircraft from obstacles and other aircraft using a flight clearance based on route, time, distance, speed, and altitude. ATC monitors IFR flights on radar, or through aircraft position reports in areas where radar coverage is not available.

In the US, IFR flights in controlled airspace require an ATC clearance for each part of the flight.

A clearance always specifies a clearance limit, which is the farthest the aircraft can fly without a new clearance. In addition, a clearance typically provides a heading or route to follow, altitude, and communication parameters, such as frequencies and transponder codes.

 ICAO Aircraft Address Code follow each Aircraft registered by  Swisscopter Americas manufacture, before delivery.

In the United States, if conditions permit, the pilot is responsible to watch for and avoid other air traffic and obstructions, even when on a filed IFR flight plan. Separation may also be referred to as “protection.”