What is Performance Based Navigation?

Performance Based Navigation (PBN) is a new concept based on the use of Area Navigation (RNAV) systems.

PBN aims to ensure global standardisation of RNAV and RNP specifications and to limit the proliferation of navigation specifications in use world-wide. It is a new concept based on the use of Area Navigation (RNAV) systems. Significantly, it is a move from a limited statement of required performance accuracy to the following:

The ICAO PBN Manual (Doc 9613) definition is:

Area navigation based on performance requirements for aircraft operating along an ATS route, on an instrument approach procedure or in a designated airspace.

Where:

Airborne performance requirements are expressed in navigation specifications in terms of accuracy, integrity, continuity and functionality needed for the proposed operation in the context of a particular airspace concept. Within the airspace concept, the availability of GNSS Signal-In-Space (SIS) or that of some other applicable navigation infrastructure has to be considered in order to enable the navigation application.

PBN is then described through means of RNAV and RNP applications with respective RNAV and RNP operations.

PBN is one of several enablers of an Airspace Concept. The others are Communications, ATS Surveillance and ATM. The PBN Concept is comprised of three components: The Navigation Specification, the Navaid Infrastructure and the Navigation Application.   

The Navigation Specification prescribes the performance requirements in terms of accuracy, integrity, continuity for proposed operations in a particular Airspace. The Navigation Specification also describes how these performance requirements are to be achieved i.e., which navigation functionalities are required to achieve the prescribed performance. Associated with the navigation specification are requirements related to pilot knowledge and training and operational approval. A Navigation Specification is either an RNP specification or an RNAV specification. An RNP specification includes a requirement for on-board self-contained performance monitoring and alerting while an RNAV specification does not.

The Navaid Infrastructure relates to ground- or space-based navigation aids that are called up in each Navigation Specification. The availability of the navaid infrastructure has to be considered in order to enable the navigation application.
 
The Navigation Application refers to the application of the Navigation Specification and Navaid Infrastructure in the context of an airspace concept to ATS routes and instrument flight procedures.

The Navigation Capability graphic depicts the overall Navigation Capability and the relationship between the navigation specifications defined within the ICAO PBN Concept.

Note: Precision approach and landing systems such as the Instrument Landing System (ILS), Microwave Landing System (MLS) and GNSS Landing System (GLS) form part of the navigation suite, but are not included within the concept of Performance-based Navigation. They differ from PBN applications in that they are not based on area navigation techniques 

The PBN Manual
 
The PBN Manual (Doc 9613) comprises two Volumes. Volume I of the PBN Manual is made up of two parts: Part A describes the PBN Concept, The Airspace Concept and how the PBN Concept is used in practice. Part B provides Implementation Guidance for ANSPs in the form of three processes. Volume II of the PBN Manual is also made up of three parts. Part A describes on-board performance monitoring and alerting and Safety Assessments, whilst Parts B and C contain ICAO’s RNAV and RNP specifications which are to be used by States as a basis for certification and operational approval.

PBN in the UK

En-route and Terminal RNAV developments in the UK have been performance-driven since their inception. Some of the impact of ICAO's PBN Concept on UK includes:
 
The B-RNAV standard contained in EASA AMC 20-4 is identical to the RNAV 5 specification in ICAO PBN. The term B-RNAV has been replaced by RNAV 5. RNAV 5 is now required for operation on all ATS routes in UK airspace.

The P-RNAV standard is not identical to the ICAO RNAV 1 specification but may be viewed as a European Application of the RNAV 1 specification. The difference between P-RNAV and RNAV1 centres on the allowable ground navigation aids and the PBN Manual identifies additional requirements for obtaining RNAV 1 approval for an operator already having approval against JAA TGL 10. In the UK the plan is to migrate from P-RNAV terminology to RNAV 1 as procedures are introduced.

Note: For the differences between P-RNAV and ICAO's RNAV 1 specification, see PBN Manual Vol. II, Part B, Chapter 3, para. 3.3.2.4.

Approach operations in the UK are already RNP Approach compliant.

All future UK navigation developments will be aligned with ICAO's PBN Strategy.