What is required for non-radar separation protection distance on either side of the route centerline?

The required non-radar separation protection distance on either side of the route centerline is 4 miles. This distance is established to ensure safe lateral separation between aircraft when radar surveillance is not available. In non-radar environments, air traffic controllers must maintain this specified distance as a precaution against potential conflicts, particularly in busy airspaces where adherence to established routes is crucial for safety. The 4-mile distance enhances the buffer zone around the route, accommodating any deviations in flight paths and providing a margin for error. This procedure is essential for maintaining safe distances, especially in areas with limited visibility or where communication with aircraft may be less frequent. By enforcing this non-radar separation standard, the safety of air traffic within controlled airspace can be maximized, while ensuring orderly flow and reducing the risk of midair collisions.