page_title: Performance-based navigation
section_title: Background
hierarchical_section_title: Performance-based navigation / Background
caption_attribution_description: English: The upper two chart strips show the current norm, while the two strips below reflect the same two approaches only with the new correct PBN-naming. ICAO member states are currently working on changing the designation. Sweden is one example of a member state who has already adopted to the new correct RNP-designation.
context_page_description: ICAO performance-based navigation specifies that aircraft required navigation performance and area navigation systems performance requirements be defined in terms of accuracy, integrity, availability, continuity, and functionality required for the proposed operations in the context of a particular airspace, when supported by the appropriate navigation infrastructure.
context_section_description: Area navigation techniques and specifications started to evolve regionally without overall ICAO guidance. This consequently meant that terms and definitions such as "RNAV" and "RNP" had slightly different meanings in different regions of the world, and even other terms could be used locally. An example of this is the term "P-RNAV" (Precision RNAV) that Europe still uses (2019), which elsewhere is called "RNAV 1".
  The terms RNAV and RNP was earlier used with little functional difference. RNP required a certain level of performance but made no attempt to define how it was to be guaranteed.
  Performance-based navigation (PBN) is ICAO's initiative to standardise terminology, specifications and meanings. One example is to standardise the terminology used around APV's (Approaches with vertical guidance). All APV's have until recently been designated as RNAV-approaches, while these in fact are RNP-approaches with respect to the PBN implementation. All APVs require on-board performance monitoring and alerting, so the system cannot only be capable of navigation down to the required degree of accuracy, but also needs to continuously monitor the performance and be capable of alerting you if its performance falls below that which is required.
  These approaches had some confusing names and designations on charts, and the changeover is currently being conducted across all member states. The two types of RNAV-approaches have traditionally been named RNAV (GNSS) and RNAV (RNP) respectively, where the former is the traditional straight-in approach from the final approach fix, and the latter is a more complex approach that curves in the horizontal plane after the final approach fix which requires authorization for it to be commenced (AR = Authorization Required). The correct naming and designation for these approaches under the PBN implementation are RNP and RNP AR respectively. The images to the right show the naming of the current charts being used, and what they will look like under PBN.
caption: The two upper chart strips show the current norm. The two strips below reflect the same two approaches only with the correct RNP-designation. "RNAV (GNSS)" becomes "RNP", and "RNAV (RNP)" becomes "RNP AR". Sweden is one example of a member state who has already adopted the new correct RNP-designation for the PBN implementation.
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