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 system performance the aircraft must demonstrate to operate in that airspace or fly that procedure.
Plain English
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.
Context Anchor
Seen in instrument procedure design, RNAV and RNP route descriptions, approach requirements, and aircraft eligibility discussions.
Derivation
Required Navigation Performance means the navigation performance that is required for a specific route or procedure. The word “level” points to the number attached to that requirement, such as RNP 1 or RNP 0.3.
Why Pilots Care
Determines the aircraft equipment, crew training, and monitoring required to fly the procedure safely and legally.
Analogy
Think of the RNP level like a lane width. A large number is a wider lane; a small number is a narrower lane. The airplane’s navigation system must be good enough to stay in that lane and warn you if it cannot.
Intuition Check
Do not read “level” as pilot experience level or difficulty level. Here it means the numeric navigation accuracy requirement; smaller numbers are tighter requirements.
Example Sentence 1
The approach required RNP 0.3, so we confirmed the FMS was showing the correct navigation performance before commencing the procedure.
Example Sentence 2
This segment of airspace allows RNP level 1 operations, permitting a larger containment area than tighter RNP values.