Definition
The spacing of aircraft maintained by air traffic control (ATC) using methods other than radar, such as time, distance, altitude, or geographic position reports from the pilots themselves.
Plain English
Keeping aircraft safely apart without using radar. Instead, the controller relies on pilot position reports and rules about time, distance, and altitude to make sure aircraft don't get too close.
Context Anchor
You may see this term in air traffic control procedures, especially for areas with limited radar coverage, oceanic operations, remote areas, or radar outages.
Derivation
Non- means 'not,' and radar comes from 'Radio Detection and Ranging.' So nonradar separation simply means separation achieved without radar — controllers use older procedural methods instead.
Why Pilots Care
Ensures continued safe operations and collision avoidance during radar outages or in remote airspace.
Intuition Check
Do not read “nonradar” as “uncontrolled.” Air traffic control is still providing separation; it is just using reports, estimates, routes, time, distance, and altitude instead of radar surveillance. Do not read “separation” as a casual amount of space. In this context, it means required minimum spacing between aircraft.
Example Sentence 1
Crossing the Atlantic, the crew operated under nonradar separation and reported each waypoint to oceanic control as required.
Example Sentence 2
In remote airspace without radar, pilots relied on nonradar separation using assigned altitudes and reported positions.