Definition
A statement of the navigation accuracy that an aircraft must achieve to operate in a given airspace, on a specific route, or during a particular procedure. RNP is expressed as a number (for example, RNP 0.3 or RNP 1) representing the lateral accuracy in nautical miles that the aircraft is expected to maintain at least 95% of the time. RNP differs from basic Area Navigation (RNAV) in that the aircraft must also have on-board performance monitoring and alerting, which warns the pilot if the system can no longer meet the required accuracy.
Plain English
RNP is a rule that says how accurately an aircraft must be able to navigate to fly a particular route or approach. The smaller the number, the tighter the accuracy required. The aircraft must also be able to check itself and warn the pilot if it can no longer fly that accurately.
Context Anchor
Seen on instrument approach charts, instrument route descriptions, and GPS or flight management system pages when selecting or flying procedures that require a stated navigation accuracy.
Derivation
‘Required’ means demanded or necessary. ‘Navigation performance’ refers to how well the aircraft can determine and hold its position. Together, the term names the level of navigation accuracy that is required for a given operation — not just desired, but mandatory.
Why Pilots Care
Determines whether an aircraft can legally and safely fly certain efficient routes and approaches.
Grounding Statement
On an RNP procedure, the airplane must stay within a defined navigation corridor and alert the pilot if it can no longer do that reliably.
Intuition Check
Do not read “performance” here as general airplane performance, like climb rate or speed. In RNP, it means navigation performance: how accurately the aircraft can follow the required path and whether it can warn the pilot when it cannot.
Example Sentence 1
The approach was labeled RNP 0.3, meaning the aircraft had to keep its position within three-tenths of a nautical mile of the centerline.
Example Sentence 2
Before starting the approach the crew confirmed the aircraft could meet the published RNP value.