ATS (air traffic services) route
A specified route designed for channeling the flow of air traffic as necessary. The term is used to mean, variously, airway, advisory route, controlled or uncontrolled route, arrival and departure route, etc. An RNAV (area navigation) ATS (air traffic services) route extends 6 NM (11.1 km) on either side of the intended track, within which RNAV-equipped aircraft can be expected to remain for 99.5% of the flight time. When warranted by density, complexity, and nature of the traffic, special routes may be established for use by low-level traffic, including, helicopters operating to and from helidecks on the high seas. The lateral spacing between such routes should take into consideration the navigation aids available and the navigation equipment carried on board. See air route.