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Performance−Based Navigation (PBN) and Area Navigation (RNAV)

Section 2. Performance−Based Navigation (PBN) and

Area Navigation (RNAV)

1−2−1. General

a. Introduction to PBN. As air travel has

evolved, methods of navigation have improved to

give operators more flexibility. PBN exists under the

umbrella of area navigation (RNAV). The term

RNAV in this context, as in procedure titles, just

means “area navigation,” regardless of the equipment

capability of the aircraft. (See FIG 1−2−1.) Many

operators have upgraded their systems to obtain the

benefits of PBN. Within PBN there are two main

categories of navigation methods or specifications:

area navigation (RNAV) and required navigation

performance (RNP). In this context, the term RNAV

x means a specific navigation specification with a

specified lateral accuracy value. For an aircraft to

meet the requirements of PBN, a specified RNAV or

RNP accuracy must be met 95 percent of the flight

time. RNP is a PBN system that includes onboard

performance monitoring and alerting capability (for

example, Receiver Autonomous Integrity Monitor-

ing (RAIM)). PBN also introduces the concept of

navigation specifications (NavSpecs) which are a set

of aircraft and aircrew requirements needed to

support a navigation application within a defined

airspace concept. For both RNP and RNAV

NavSpecs, the numerical designation refers to the

lateral navigation accuracy in nautical miles which is

expected to be achieved at least 95 percent of the

flight time by the population of aircraft operating

within the airspace, route, or procedure. This

information is detailed in International Civil Aviation

Organization’s (ICAO) Doc 9613, Performance−

based Navigation (PBN) Manual and the latest FAA

AC 90−105, Approval Guidance for RNP Operations

and Barometric Vertical Navigation in the U.S.

National Airspace System and in Remote and

Oceanic Airspace.

FIG 1−2−1

Navigation Specifications