Definition
A defined block of airspace, route, or procedure in which the aircraft must keep its actual position within a specified lateral distance of the intended track for a stated percentage of the flight time, typically 95%. The required value is published as an RNP number expressed in nautical miles (for example, RNP 1 means staying within 1 NM of centerline). Aircraft operating in RNP airspace must use approved navigation systems capable of meeting that performance and must monitor and alert the crew if the system is no longer meeting it.
Plain English
Airspace where you are only allowed to fly if your navigation equipment can keep you within a set distance of the planned track, and warn you if it stops being that accurate.
Context Anchor
Seen in IFR route planning, instrument procedures, and airspace requirements where specific navigation capability is required before using a route or procedure.
Derivation
"Required" sets the rule, "Navigation Performance" refers to how accurately the aircraft can hold its track. The phrase was coined by ICAO to shift focus from which equipment is installed to how well the aircraft actually navigates, regardless of the equipment used.
Why Pilots Care
Meeting the RNP standard allows access to efficient routes, lower minima, and tighter traffic separation in busy or constrained airspace; failing to meet it means the flight cannot enter that airspace.
Intuition Check
Do not read “performance” here as aircraft climb, speed, or engine performance. In this term, performance means navigation accuracy and the ability of the equipment to warn you when that accuracy is not good enough.
Example Sentence 1
Before entering RNP 2 airspace on the oceanic crossing, the crew confirmed that both navigation systems were operating and that the aircraft was approved for the route.
Example Sentence 2
During the arrival briefing the crew noted the approach entered RNP airspace, requiring continuous monitoring of the navigation performance display.