nonradar

Nonradar refers to airspace or operations conducted without radar surveillance. In a nonradar environment, air traffic control relies on procedural separation and coordination with pilots rather than radar vectors. Controllers issue clearances and instructions based on pilots’ position reports, time estimates, and known fixes, and pilots navigate by conventional navigation aids and published routes.

Operations without radar typically use a combination of pilot navigation, voice communications, and discrete surveillance methods when available. Aircraft may be tracked by position reports at designated fixes, routes, or waypoints, and by time-based or distance-based separations. Modern nonradar procedures often incorporate capabilities such as ADS-B, CPDLC, and GPS-based navigation to improve situational awareness and communication, even though radar surveillance is not relied upon for surveillance.

Common settings for nonradar operations include oceanic and remote continental airspace, mountain regions with limited radar coverage, and areas experiencing radar outages. In these areas, procedures emphasize coordination, standard routes, and conservative separation standards to maintain safety in the absence of continuous radar monitoring. Events such as weather or equipment failures can reduce nonradar efficiency, prompting a temporary reintroduction of radar or alternative surveillance methods.

Safety and efficiency considerations center on pilot responsibility for navigation and position reporting, controller workload, and the availability of alternative surveillance and communication systems. Nonradar environments aim to maintain safe, orderly flow of traffic through procedural control, though they typically support lower capacity and greater reliance on accurate pilot navigation and timely position reports than radar-surveilled airspace.