The concept of Required Navigation Performance (RNP) is to determine the accuracy of the aircraft navigation system and has been developed for use in en-route navigation. The fundamental feature is that it only defines a standard of equipment performance therefore it is of no interest to controller how the navigation is achieved but only that the aircraft is equipped to the standard required in a particular piece of airspace. IFATCA recognises that the extension of the RNP concept to the approach and landing phases of flight appears to offer advantages to ATC.

ICAO is introducing the Performance Based Navigation concept to provide a means of achieving harmonisation of RNAV and RNP applications. The PBN Manual (Doc 9613) sets out issues associated with the identification of the advantages and limitations of choosing one or the other as the navigation requirement for an airspace concept.