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6/17/21 

AIM 

or avionics failure. The Aircraft Flight Manual 
(AFM) or avionics documents for your aircraft 
should specifically state the aircraft’s RNP eligibili-
ties. Contact the manufacturer of the avionics or the 
aircraft if this information is missing or incomplete. 
NavSpecs should be considered different from one 
another, not “better” or “worse” based on the 
described lateral navigation accuracy. It is this 
concept that requires each NavSpec eligbility to be 
listed separately in the avionics documents or AFM. 
For example, RNP 1 is different from RNAV 1, and 
an RNP 1 eligibility does NOT mean automatic RNP 
2 or RNAV 1 eligibility. As a safeguard, the FAA 
requires that aircraft navigation databases hold only 
those procedures that the aircraft maintains eligibility 
for. If you look for a specific instrument procedure in 
your aircraft’s navigation database and cannot find it, 
it’s likely that procedure contains PBN elements your 
aircraft is ineligible for or cannot compute and fly. 
Further, optional capabilities such as Radius

to

fix 

(RF) turns or scalability should be described in the 
AFM or avionics documents. Use the capabilities of 
your avionics suite to verify the appropriate waypoint 
and track data after loading the procedure from your 
database. 

b.  PBN Operations. 

1.  Lateral Accuracy Values. 

Lateral Accuracy 

values are applicable to a selected airspace, route, or 
procedure. The lateral accuracy value is a value 
typically expressed as a distance in nautical miles 
from the intended centerline of a procedure, route, or 
path. RNP applications also account for potential 
errors at some multiple of lateral accuracy value (for 
example, twice the RNP lateral accuracy values). 

(a)  RNP NavSpecs.

 U.S. standard NavSpecs 

supporting typical RNP airspace uses are as specified 
below. Other NavSpecs may include different lateral 
accuracy values as identified by ICAO or other states. 
(See FIG 1

2

1.) 

(1)  RNP Approach (RNP APCH). 

In the 

U.S., RNP APCH procedures are titled RNAV (GPS) 
and offer several lines of minima to accommodate 
varying levels of aircraft equipage: either lateral 
navigation (LNAV), LNAV/vertical navigation 
(LNAV/VNAV), Localizer Performance with Verti-
cal Guidance (LPV), and Localizer Performance 
(LP). GPS with or without Space

Based Augmenta-

tion System (SBAS) (for example, WAAS) can 
provide the lateral information to support LNAV 

minima. LNAV/VNAV incorporates LNAV lateral 
with vertical path guidance for systems and operators 
capable of either barometric or SBAS vertical. Pilots 
are required to use SBAS to fly to the LPV or LP 
minima. RF turn capability is optional in RNP APCH 
eligibility. This means that your aircraft may be 
eligible for RNP APCH operations, but you may not 
fly an RF turn unless RF turns are also specifically 
listed as a feature of your avionics suite. GBAS 
Landing System (GLS) procedures are also con-
structed using RNP APCH NavSpecs and provide 
precision approach capability. RNP APCH has a 
lateral accuracy value of 1 in the terminal and missed 
approach segments and essentially scales to RNP 0.3 
(or 40 meters with SBAS) in the final approach. (See 
Paragraph 5

4

18, RNP AR Instrument Approach 

Procedures.) 

(2)  RNP Authorization Required Ap-

proach (RNP AR APCH).

 In the U.S., RNP AR 

APCH procedures are titled RNAV (RNP). These 
approaches have stringent equipage and pilot training 
standards and require special FAA authorization to 
fly. Scalability and RF turn capabilities are 
mandatory in RNP AR APCH eligibility. RNP AR 
APCH vertical navigation performance is based upon 
barometric VNAV or SBAS. RNP AR is intended to 
provide specific benefits at specific locations. It is not 
intended for every operator or aircraft. RNP AR 
capability requires specific aircraft performance, 
design, operational processes, training, and specific 
procedure design criteria to achieve the required 
target level of safety. RNP AR APCH has lateral 
accuracy values that can range below 1 in the terminal 
and missed approach segments and essentially scale 
to RNP 0.3 or lower in the final approach. Before 
conducting these procedures, operators should refer 
to the latest AC 90

101, Approval Guidance for RNP 

Procedures with AR. (See paragraph 5

4

18.) 

(3)  RNP Authorization Required Depar-

ture (RNP AR DP).

 Similar to RNP AR approaches, 

RNP AR departure procedures have stringent 
equipage and pilot training standards and require 
special FAA authorization to fly. Scalability and RF 
turn capabilities is mandatory in RNP AR DP 
eligibility. RNP AR DP is intended to provide 
specific benefits at specific locations. It is not 
intended for every operator or aircraft. RNP AR DP 
capability requires specific aircraft performance, 
design, operational processes, training, and specific 
procedure design criteria to achieve the required 

Performance

Based Navigation (PBN) and Area Navigation (RNAV) 

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