Required Navigation Performance

What is RNP?

Required Navigation Performance is an advanced form of Area Navigation that adds a critical capability: onboard monitoring and alerting. While standard RNAV simply computes a position, RNP continuously checks whether the navigation system can guarantee a specific accuracy level. If the system detects that it cannot maintain the required performance, it alerts the flight crew immediately, allowing them to take corrective action or execute a missed approach.

The most significant variant is RNP AR (Authorization Required), which permits curved approach paths with lateral accuracy as tight as 0.1 nautical miles. This enables approaches into airports surrounded by terrain that would otherwise require visual conditions or straight-in ILS alignment. Airports like Innsbruck, Queenstown, and Kathmandu benefit enormously from RNP AR procedures, as they allow airlines to maintain schedules in weather conditions that previously forced diversions.

RNP specifications are numbered by their accuracy requirement in nautical miles. RNP 4 is used for oceanic operations, RNP 1 for terminal areas, and RNP 0.3 for approach procedures. The smaller the number, the tighter the required accuracy, and the more the system depends on high-quality GNSS signals to function correctly.

Why It Matters for Airspace Risk

RNP approaches are almost entirely dependent on GPS/GNSS signals. The onboard monitoring component can detect when GPS quality degrades, but detection does not solve the problem — it simply tells the crew they can no longer fly the procedure. In GPS-denied environments, RNP approaches fail. The crew must execute a missed approach and divert or request radar vectors, which may not be available at remote or terrain-constrained airports.

This creates a compounding risk at airports that were designed around RNP AR as their primary instrument approach. If an airport decommissioned its conventional approach infrastructure, GPS denial effectively closes the airport to instrument arrivals. The eastern Mediterranean GPS interference zone has already demonstrated this: airports in Cyprus and Lebanon that rely on RNAV/RNP approaches have experienced repeated procedure unavailability, forcing diversions and delays that cascade through European networks.

Key Facts

• •RNP adds onboard monitoring and alerting to RNAV — the aircraft knows when its navigation accuracy degrades.
• •RNP AR approaches can follow curved paths with 0.1 NM accuracy, navigating terrain that conventional approaches cannot.
• •Airlines require specific crew training and aircraft certification for RNP AR operations.
• •GPS jamming or spoofing triggers RNP alerts, forcing missed approaches at airports with no conventional backup.
• •ICAO classifies RNP within the PBN framework alongside RNAV, but with stricter equipment and operational requirements.

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