RNP procedures were introduced in the PANS-OPS (ICAO Doc 8168), which became applicable in 1998. RNP approaches with RNP values currently down to 0.1 allow aircraft to follow precise three-dimensional curved flight paths through congested airspace, around noise sensitive areas, or through difficult terrain. This is not only a major advantage for air traffic operations, but presents a major cost-savings opportunity for airlines flying over the oceans due to less restrictive routing and better available altitudes. Improved accuracy of on-board RNP systems represent a significant advantage to traditional non-radar environments, since the number of aircraft that can fit into a volume of airspace at any given altitude is a square of the number of required separation that is to say, the lower the RNP value, the lower the required distance separation standards, and in general, the more aircraft can fit into a volume of airspace without losing required separation. The level of RNP an aircraft is capable of determines the separation required between aircraft with respect to distance. Some oceanic airspace has an RNP capability value of 4 or 10. The differences in these systems are typically a function of on-board navigational system redundancies.Ī related term is ANP which stands for "actual navigation performance." ANP refers to the current performance of a navigation system while "RNP" refers to the accuracy required for a given block of airspace or a specific instrument procedure. An RNP of 0.3 means the aircraft navigation system must be able to calculate its position to within a circle with a radius of 3/10 of a nautical mile. An RNP of 10 means that a navigation system must be able to calculate its position to within a circle with a radius of 10 nautical miles.
RNP also refers to the level of performance required for a specific procedure or a specific block of airspace. Therefore, if ATC radar monitoring is not provided, safe navigation in respect to terrain shall be self-monitored by the pilot and RNP shall be used instead of RNAV. One not having such a requirement is referred to as an RNAV specification. A navigation specification that includes a requirement for on-board navigation performance monitoring and alerting is referred to as an RNP specification.
The key difference between them is the requirement for on-board performance monitoring and alerting. Required navigation performance ( RNP) is a type of performance-based navigation (PBN) that allows an aircraft to fly a specific path between two 3D-defined points in space.Īrea navigation (RNAV) and RNP systems are fundamentally similar. RNP-AR 3D approach tracks to Cajamarca, Perú (above) and La Serena, Chile (below), demonstrating the benefits of precise lateral and vertical navigation on airports located on mountainous regions