Definition
The spacing between aircraft maintained by air traffic control without the use of radar, using procedural methods such as time, distance, altitude, geographic position reports, or holding patterns to keep aircraft safely apart.
Plain English
Keeping aircraft apart without using radar. Controllers rely on the pilots' position reports and on rules about time, distance, and altitude to make sure aircraft stay clear of each other.
Context Anchor
Pilots may encounter this in areas without radar coverage, over remote or oceanic routes, or during a radar outage.
Derivation
From Latin 'non' (not) and 'radar' (Radio Detection And Ranging). 'Separation' comes from Latin 'separare' meaning 'to set apart.' Together: keeping aircraft set apart without radar.
Why Pilots Care
Ensures collision avoidance and safe traffic flow when radar services are unavailable, directly affecting route choices and separation standards.
Intuition Check
Do not read “nonradar” as “uncontrolled.” Nonradar separation still means ATC is separating aircraft; it just means the controller is doing it without radar position information.
Example Sentence 1
Crossing the Atlantic, the crew operated under nonradar separation and made position reports at each waypoint.
Example Sentence 2
Over the ocean the flight maintained nonradar separation by staying on its assigned track and reporting position every thirty minutes.