background image

AIM 

4/20/23 

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 Vertical Guidance (LPV), and 

Localizer Performance (LP). GPS with or without Space

Based Augmentation 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 constructed 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 (Authorization Required) 

Instrument Procedures.) 

(2) RNP Authorization Required Approach (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 Departure (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 target level of safety. RNP AR DP has lateral accuracy values 

that can scale to no lower than RNP 0.3 in the initial departure flight path. 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.

1

2

Performance

Based Navigation (PBN) and Area Navigation (RNAV)