Plain English Meaning

A navigation standard that says the aircraft has to stay within 1 nautical mile of the planned track 95 percent of the time, and the system itself has to warn the pilot if it can no longer guarantee that accuracy.

Full Definition

A Required Navigation Performance level specifying that an aircraft must be able to maintain its actual position within 1.0 nautical mile of the intended flight path for at least 95 percent of the total flight time, with onboard performance monitoring and alerting if that accuracy cannot be met.

Context Anchor

Seen on and descriptions where a or requires a navigation accuracy.