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AIM

10/12/17

1

−2−1

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

2/28/19

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