Plain English Meaning

An RNP level is a number that tells you how tightly the aircraft must stay on its planned track. The smaller the number, the tighter the required accuracy. RNP 1 means stay within 1 nautical mile of the path most of the time; RNP 0.3 means stay within 0.3 nautical miles.

Full Definition

A Required Navigation Performance (RNP) level is a numerical value, expressed in nautical miles, that defines the lateral navigation accuracy an aircraft must maintain for at least 95% of the flight time within a given airspace, route, or procedure. For example, RNP 1 requires the aircraft to remain within 1 NM of the intended track 95% of the time, RNP 0.3 within 0.3 NM, and so on. The RNP level dictates the navigation the aircraft must demonstrate to operate in that airspace or fly that procedure.