Definition
A statement of the navigation accuracy, expressed in nautical miles, that an aircraft must achieve to fly within a defined airspace, route, or procedure. An RNP value (for example, RNP 1.0 or RNP 0.3) means the aircraft must remain within that distance of its intended path for 95% of the flight time, and the onboard navigation system must be able to monitor its own performance and alert the crew if the required accuracy cannot be maintained.
Plain English
RNP is a rule that says how accurately an aircraft must be able to fly a given route or approach. The number tells you how close to the centerline the aircraft has to stay, and the system itself has to watch its own accuracy and warn the pilot if it slips.
Context Anchor
Pilots see RNP on instrument procedure charts, route requirements, aircraft capability documents, and clearances for certain routes or approaches.
Derivation
The name describes the idea directly: a level of navigation performance that is required to use a given piece of airspace or procedure. The shift in thinking it represents — defining the accuracy needed rather than the equipment used — is what makes the term meaningful.
Why Pilots Care
It determines which precise routes and approaches an aircraft is authorized to fly, affecting access to certain airports and airspace.
Grounding Statement
On an RNP segment, the aircraft must stay close enough to the published path and warn the pilot if it cannot.
Intuition Check
“Performance” does not mean how fast or powerful the aircraft is here. In RNP, it means how accurately the aircraft can navigate along the required path and whether it can warn the crew when that accuracy is not being met.
Example Sentence 1
The approach chart showed RNP 0.3, so the crew confirmed the aircraft was approved for that level of performance before accepting the clearance.
Example Sentence 2
RNP 0.3 was needed for the tight final approach segment into the mountain airport.