Required navigation performance (RNP) is RNAV with onboard navigation monitoring and alerting. RNP is also a statement of navigation performance necessary for operation within a defined airspace. A critical component of RNP is the ability of the aircraft navigation system to monitor its achieved navigation performance, and to identify for the pilot whether the operational requirement is, or is not being met during an operation. This onboard performance monitoring and alerting capability; therefore, allows a lessened reliance on ATC intervention (via radar monitoring, automatic dependent surveillance-broadcast (ADS-B), multilateration, communications), and/or route separation to achieve the overall safety of the operation. RNP capability of the aircraft is a major component in determining the separation criteria to ensure that the overall containment of the operation is met.
The RNP capability of an aircraft varies depending upon the aircraft equipment and the navigation infrastructure. For example, an aircraft may be equipped and certified for RNP 1.0, but may not be capable of RNP 1.0 operations due to limited NAVAID coverage.
RNP Levels
An RNP level or type is applicable to a selected airspace, route, or procedure. As defined in the Pilot/Controller Glossary, the RNP level or type is a value typically expressed as a distance in nautical miles from the intended centerline of a procedure, route, or path. RNP applications also account for potential errors at some multiple of RNP level (e.g., twice the RNP level).
Standard RNP Levels
United States standard values supporting typical RNP airspace are shown in Figure. Other RNP levels as identified by ICAO, other states, and the FAA may also be used.
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| U.S. standard RNP levels |
Application of Standard RNP Levels
United States standard levels of RNP typically used for various routes and procedures supporting RNAV operations may be based on use of a specific navigational system or sensor, such as GPS, or on multi-sensor RNAV systems having suitable performance.
Note: The performance of navigation in RNP refers not only to the level of accuracy of a particular sensor or aircraft navigation system, but also to the degree of precision with which the aircraft is flown. Specific required flight procedures may vary for different RNP levels.
