2-2
2.5 Aircraft Eligibility and Aircraft Modification. Aircraft eligibility provided in this AC provides guidance for an operator to determine if their aircraft is capable of conducting these operations. This guidance is not appropriate for conducting any modifications to aircraft type design. Detailed and complete airworthiness guidance is available in AC 20-138( ) and should be used by all airworthiness applicants.
3-1 CHAPTER 3. DOCUMENTATION
3.1 Cancellation. Advisory Circular (AC) 90-105, Approval Guidance for RNP Operations and Barometric Vertical Navigation in the U.S. National Airspace System is cancelled.
AC 90-94, Guidelines for Using Global Positioning System Equipment for IFR En Route and Terminal Operations and for Nonprecision Instrument Approaches in the U.S.
National Airspace System (dated 12/14/1994) and AC 90-97, Use of Barometric Vertical Navigation (VNAV) for Instrument Approach Operations Using Decision Altitude (dated 10/19/2000) were cancelled with the publication of AC 90-105 (dated 1/23/2009).
Note: Guidance from Federal Aviation Administration (FAA) Order 8400.33, Procedures for Obtaining Authorization for Required Navigation Performance 4 (RNP-4) Oceanic and Remote Area Operations, and FAA Order 8400.12C, Required Navigation Performance 10 (RNP 10) Operational Authorization, are included in this AC.
3.2 FAA ACs and Orders. Please refer to the links provided in the bullets of paragraph 2.4 to obtain the latest ACs and/or orders.
• AC 20-138( ), Airworthiness Approval of Positioning and Navigation Systems.
• AC 20-153( ), Acceptance of Aeronautical Data Processes and Associated Databases.
• AC 23.1309-1( ), System Safety Analysis and Assessment for Part 23 Airplanes.
• AC 25.1309-1( ), System Design and Analysis.
• AC 25-15( ), Approval of Flight Management Systems in Transport Category Airplanes.
• AC 90-100( ), U.S. Terminal and En Route Area Navigation (RNAV) Operations.
• AC 90-101( ), Approval Guidance for RNP Procedures with AR.
• AC 90-107( ), Guidance for Localizer Performance with Vertical Guidance and Localizer Performance without Vertical Guidance Approach Operations in the U.S. National Airspace System.
• AC 91-70( ), Oceanic and International Operations.
• AC 120-29( ), Criteria for Approval of Category I and Category II Weather Minima for Approach.
• Order 7110.82, Reporting Oceanic Errors.
• Order 7400.11( ), Airspace Designations and Reporting Points.
• Order 8260.3( ), United States Standard for Terminal Instrument Procedures (TERPS).
• Order 8260.19( ), Flight Procedures and Airspace.
• Order 8260.42( ), United States Standard for Helicopter Area Navigation (RNAV).
3-2
• Order 8260.46( ), Departure Procedure (DP) Program.
• Order 8260.58( ), United States Standard for Performance Based Navigation (PBN) Instrument Procedure Design.
3.3 Related Regulations Title 14 of the Code of Federal Regulations (14 CFR).
• Part 71, §§ 71.31 and 71.71.
• Part 91, § 91.123, 91.175, 91.205, and Subpart H.
• Part 95.
• Part 97, § 97.20.
• Part 121, §§ 121.349, 121.351, and 121.567, Appendix G.
• Part 125, §§ 125.203, 125.287, and 125.325.
• Part 129, § 129.17.
• Part 135, § 135.165.
3.4 FAA Technical Standard Orders (TSO).
• TSO-C106, Air Data Computer.
• TSO-C115b, Airborne Area Navigation Equipment Using Multisensor Inputs.
• TSO-C115c or later, Airborne Area Navigation Equipment Using Multisensor Inputs.
• TSO-C129a, Airborne Supplemental Navigation Equipment Using the Global Positioning System (GPS).
• TSO-C145, Airborne Navigation Sensors Using the Global Positioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS).
• TSO-C146, Stand-Alone Airborne Navigation Equipment Using the Global Positioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS).
• TSO-C196, Airborne Supplemental Navigation Sensors for Global Positioning System Equipment using Aircraft-Based Augmentation.
3.5 RTCA Documents. Copies of the following RTCA, Inc. documents may be obtained from RTCA, Inc., 1150 18th Street NW, Suite 910, Washington, DC 20036, or purchased online at https://my.rtca.org/nc__store.
• RTCA/DO-178( ), Software Considerations in Airborne Systems and Equipment Certification.
• RTCA/DO-187( ), Minimum Operational Performance Standards for Airborne Area Navigation Equipment Using Multi-Sensor Inputs.
• RTCA/DO-201( ), Standards for Aeronautical Information.
3-3
• RTCA/DO-208( ), Minimum Operational Performance Standards for Airborne Supplemental Navigation Equipment Using Global Positioning System (GPS).
• RTCA/DO-229( ), Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment.
• RTCA/DO-236( ), Minimum Aviation System Performance Standards: Required Navigation Performance for Area Navigation.
• RTCA/DO-283( ), Minimum Operational Performance Standards for Required Navigation Performance for Area Navigation.
• RTCA/DO-316( ), Minimum Operational Performance Standards for Global Positioning System/Aircraft -based Augmentation System Airborne Equipment.
3.6 Other Documents. Copies of the International Civil Aviation Organization (ICAO) documents may be obtained from Document Sales Unit, ICAO, 999 Robert-Bourassa Boulevard, Montreal, Quebec, H3C 5H7, Canada:
• ICAO Doc 9613, Performance Based Navigation (PBN) Manual.
• ICAO Doc 4444 PANS ATM, Procedures for Air Navigation Services, Air Traffic Management.
• ICAO Doc 7030, Regional Supplementary Procedures (SUPPS).
• Aeronautical Information Publications (AIP), United States, 2020.
4-1 CHAPTER 4. GENERAL INFORMATION
4.1 Performance-Based Navigation (PBN) Concept. The PBN concept represents a shift from ground-based navigation to Area Navigation (RNAV). Performance requirements are identified in navigation specifications (Nav Spec) (e.g., the requirements in this advisory circular (AC)), which also identify the choices of navigation sensors, navigation equipment, operational procedures, and training needed to meet the performance requirements.
4.1.1 Components. The PBN concept specifies aircraft Required Navigation Performance (RNP) system performance requirements in terms of accuracy, integrity, availability, continuity, and functionality needed for particular operations or airspace. The Navigation Application is achieved by the use of a Navigational Aid (NAVAID) infrastructure and associated Nav Spec (See Figure 4-1, Performance-Based Navigation Concept).
Figure 4-1. Performance-Based Navigation Concept
4.1.1.1 Navigation Application. This is defined as the application of a Nav Spec and the supporting NAVAID infrastructure, to routes, procedures, and/or defined airspace volume, in accordance with the intended airspace concept. For example, in the terminal area, the Nav Spec is RNP 1 with an accuracy of 1 nautical mile (NM). The NAVAID infrastructure would be Global Navigation Satellite System (GNSS) or distance measuring equipment (DME)/DME.
4.1.1.2 NAVAID Infrastructure. NAVAID infrastructure refers to space-based and/or ground-based NAVAIDs available to meet the requirements in the Nav Spec.
4.1.1.3 Nav Spec. A set of aircraft and aircrew requirements needed to support PBN operations within a defined airspace. There are two kinds of Nav Spec:
4-2
1. RNAV specification. A Nav Spec based on area navigation that does not include the requirement for onboard performance monitoring and alerting, designated by the prefix RNAV
(e.g., RNAV 5, RNAV 1).
2. RNP specification. A Nav Spec based on area navigation that includes the requirement for onboard performance monitoring and alerting, designated by the prefix RNP (e.g., RNP 4, Required Navigation Performance Approach (RNP APCH).
Note: The Performance-based Navigation Manual (Doc 9613), Volume II, contains additional information on Nav Specs.
4.1.2 Lateral Performance. For oceanic/remote, en route and terminal phases of flight, PBN is limited to operations with linear lateral performance requirements and time constraints due to legacy reasons associated with the previous RNP concept. In the approach phases of flight, PBN accommodates both linear and angular laterally guided operations.
4.1.2.1 RNP Values. The RNP value (also known as lateral navigation accuracy) designates the 95 percent lateral navigation (LNAV) performance (in NM) and the related monitoring and alerting requirements associated with an RNP instrument flight operation or a particular segment of that instrument flight.
RNP values are specified in NM (e.g., RNP 0.3).
4.1.3 Vertical Performance. Some Nav Specs include requirements for vertical guidance using augmented GNSS or barometric vertical navigation (baro-VNAV) (see Appendix B).
However, these requirements do not constitute vertical RNP which is neither defined nor included in the PBN Concept.
4.1.4 Onboard Performance Monitoring and Alerting. Onboard performance monitoring and alerting is the main element that determines if the navigation system complies with the necessary safety level associated to an RNP application. It relates to both lateral and longitudinal navigation performance; and it allows the aircrew to detect that the navigation system is not achieving, or cannot guarantee with 10-5 integrity, the navigation performance required for the operation. RNP systems provide improvements on the integrity of operations; this may permit closer route spacing and can provide sufficient integrity to allow only RNP systems to be used for navigation in a specific airspace. The use of RNP systems may therefore offer significant safety, operational and efficiency benefits.
4.2 Procedures and Routes. RNP procedures and routes require the use of RNAV systems with onboard performance monitoring and alerting. A critical component of RNP is the ability of the aircraft navigation system in combination with the pilot to monitor its achieved navigation performance and to identify for the pilot whether the operational requirement is or is not being met during an operation.
Note: Compliance with the performance monitoring and alerting requirement does not imply an automatic monitor of Flight Technical Error (FTE). The
4-3 onboard monitoring and alerting function should consist at least of a Navigation System Error (NSE) or Position Estimation Error (PEE) monitoring and alerting algorithm and a lateral deviation display enabling the crew to monitor the FTE.
To the extent operational procedures are used to monitor FTE, the crew procedure, equipment characteristics, and installation are evaluated for their effectiveness and equivalence as described in the functional requirements and operating procedures. Path Definition Error (PDE) is considered negligible due to the database integrity process (see Chapter 10, Database Integrity) and crew procedures.
Figure 4-2. Total System Error (TSE) N ote 1: When evaluating RNP compliance, consideration must be given to possible error sources. Figure 4-2 displays possible cross-track (XTK) errors that can occur with definitions provided in paragraph 4.3.
Note 2: PDE is negligible and assumed to be zero. NSE is used instead of PEE and FTE is used instead of Path Steering Error (PSE) because they are considered equivalent and are the industry preferred terms.
4.3 Navigation Error Components/Definitions. Also in Appendix J, Administrative Information.
4.3.1 Flight Technical Error (FTE) or Path Steering Error (PSE). The accuracy with which the aircraft is controlled as measured by the indicated aircraft position, with respect to the indicated command or desired position is the FTE. It does not include blunder errors.
4.3.1.1 Display Error. As a component of FTE, these errors may include error components contributed by any input, output, or signal conversion equipment used by the display as it presents either aircraft position or guidance commands (e.g., course deviation or command heading) and by any course definition entry device employed.
4-4
4.3.2 Path Definition Error (PDE). This is the difference between the defined path and the desired path at a specific point.
4.3.3 Navigation System Error (NSE) or Position Estimation Error (PEE). The difference between true position and estimated position.
4.3.4 Total System Error (TSE). The difference between the true position and the desired position and is equal to the vector sum of the FTE, PDE, and NSE.
4.3.5 Position Estimation Error (PEE) or Navigation System Error (NSE). PEE or NSE is the difference between true position and estimated position.
5-1 CHAPTER 5. APPLICATIONS OF REQUIRED NAVIGATION PERFORMANCE (RNP) OPERATIONS
5.1 Overview. RNP operations as defined in this advisory circular (AC) are the application of navigation specification (Nav Spec) to a particular phase of flight. The columns of Table 5-1 contain RNP values (if applicable) for RNP operations in each phase of flight.
RNP 1 requires an RNP value of 1 for arrival and departures in the terminal area and is also used in the initial, intermediate, and missed approach phase. RNP 2 is for both domestic and oceanic/remote continental operations with an RNP value of 2. RNP 4 and 10 are for oceanic and remote continental operations only with RNP values of 4 and 10 respectively. Advanced Required Navigation Performance (A-RNP) includes an RNP value of 2 for oceanic and remote continental operations and may have a 2 or 1 value for domestic en route segments. Except for the Final Approach Segment (FAS), advanced RNP allows scalability with a range from 1 to 0.3 as routing boundaries will gradually expand from 0.3 to greater values on departures/missed approaches and narrow on arrivals/approaches. Required Navigation Performance Approach (RNP APCH) operations have RNP values of 1 until the FAS where the boundaries narrow to RNP 0.3;
the RNP value expands back to RNP 1 in the missed approach segment. Lastly, rotorcraft RNP 0.3 requires an RNP value of 0.3 for all phases of flight except for oceanic and remote continental and the FAS.
Table 5-1. Applications of RNP Operations Flight Phase Navigation Specifications Terminal Approach Terminal En route Oceanic/Remote Continental En route Domestic Arrival Initial Intermediate Final Missed Departure RNP 1 N/A N/A 1 1 1 N/A 1 1 RNP 2 2 2 N/A N/A N/A N/A N/A N/A RNP 4 4 N/A N/A N/A N/A N/A N/A N/A RNP 10 10 N/A N/A N/A N/A N/A N/A N/A A-RNP 2 2 or 1 1 – 0.3 1 – 0.3 1 – 0.3 N/A 0.3 - 1 0.3 - 1 RNP APCH N/A N/A N/A 1 1 0.3 1 N/A RNP 0.3 N/A 0.3 0.3 0.3 0.3 N/A 0.3 0.3 Note 1: N/A: Not Applicable Note 2: Except for RNP APCH, all the final blocks are intentionally labeled N/A.
Note 3: RNP 1 and A-RNP may be used in combination with any type of approach (RNP, instrument landing system (ILS), Ground Based Augmentation System (GBAS) Landing System (GLS)).
Note 4: RNP 0.3 applies to Domestic (Rotorcraft) Operations.
6-1 CHAPTER 6. OPERATIONAL GUIDANCE FOR REQUIRED NAVIGATION
PERFORMANCE (RNP) OPERATIONS
6.1 General. This section provides guidance on the operational aspects that must be considered for conduct of all RNP operations. Additional guidance that is specific to each RNP navigation specification (Nav Spec) is provided in the appendices to this advisory circular (AC), including how to determine if your aircraft is eligible for the operation. In addition to this guidance, the operator must continue to ensure they comply with the general operating requirements, including checking Notices to Airmen (NOTAM), availability of Navigational Aids (NAVAID), airworthiness of aircraft systems, and aircrew qualification.
6.2 Centerline. All pilots are expected to maintain centerline, as depicted by onboard lateral deviation indicators and/or flight guidance during all RNP operations described in this AC unless authorized to deviate by air traffic control (ATC) or under emergency conditions. For normal operations, the cross-track (XTK) error/deviation (the difference between the RNP system computed path and the aircraft position relative to the path) should be limited to ±½ the RNP value. Brief deviations from this standard
(e.g., overshoots or undershoots) during track changes (flyby and flyover turns), up to a maximum of one times the RNP value are allowable.
6.3 RNP En Route, RNP Terminal, and RNP APCH Operations:
1. The pilot is not required to monitor ground-based NAVAIDs used in position updating unless specified by the Airplane Flight Manual (AFM).
2. The pilot must comply with published and assigned altitudes, and airspeeds.
Note: Pilots operating aircraft with a barometric vertical navigation (baro-VNAV) system must ensure compliance with all altitude constraints as published in the procedure by reference to the barometric altimeter.
6.4 RNP Operational Transitions.
6.4.1 Transitions to Instrument Landing System (ILS), Ground Based Augmentation System (GBAS) Landing System (GLS), Localizer Performance with Vertical Guidance (LPV) or Conventional Approach Procedures. In order to fly RNP transitions to an ILS or GLS final approach course, or from an ILS or GLS approach with an RNP missed approach, pilots must comply with the operating requirements of this AC (see Appendices A (Required Navigation Performance Approach (RNP APCH)), C (RNP 1), and/or H (Advanced Required Navigation Performance (A-RNP)). RNP systems used for this type of operation must allow for a means to become established prior to the final approach fix (FAF) on an ILS or GLS or LPV final with minimal overshoot or undershoot. The pilot must ensure the appropriate navigation mode is selected/armed and that the Final Approach Segment (FAS) course and glideslope are correctly captured. Pilots must verify lateral and vertical capture on ILS procedures.
6-2 Note 1: Charts for ILS and GLS procedures with RNP transitions will contain notes specifying the requirement for suitable RNP capability. These RNP transitions are also identified by the use of waypoint symbols on the procedure.
Note 2: Pilots must pay close attention to the navigation source of both lateral and vertical axis. When transitioning from an RNP segment to a precision approach segment, it is possible for the lateral precision navigation source to acquire prior to capture of the vertical precision navigation source.
Note 3: Additional criteria for operation on ILS, LPV final and GLS approaches with Radius to Fix (RF) transitions are covered in Appendix I, Additional Capabilities.
6.5 Oceanic/Remote Continental Airspace and Offshore Airspace.
6.5.1 Airspace Distinction. For continuity purposes, there is a distinction between oceanic, remote continental, and offshore operations. The paragraphs below define these Areas of Operation.
6.5.1.1 Oceanic. Oceanic airspace is defined as international airspace over oceans where separation and procedures are in accordance with the International Civil Aviation Organization (ICAO), and outside the area defined as offshore.
Responsibility for the provision of ATC service in this airspace is delegated to various countries. Controllers provide Air Traffic Services (ATS) utilizing procedural control and procedural separation.
6.5.1.2 Remote Continental. Remote continental airspace is defined as airspace above terrain where line-of-sight communications, independent surveillance and reliable ground-based NAVAIDs are not available. Controllers provide ATS utilizing procedural control and procedural separation.
6.5.1.3 Offshore. Offshore airspace is defined by Title 14 of the Code of Federal Regulations (14 CFR) part 71, §§ 71.31 and 71.71, and part 91, § 91.511. It is designated in international airspace within areas of domestic radio navigational signal or ATC radar coverage, and within which domestic ATC procedures are applied. For more details, refer to Federal Aviation Administration (FAA) Order 7400.11( ), Airspace Designations and Reporting Points. All certificated operators, and all large and turbine-powered multiengine aircraft, must have two independent RNP navigation systems appropriate for the route to be flown, or a single RNP navigation system and a second navigation system capable of proceeding to a safe landing from anywhere on the route.
7-1 CHAPTER 7. OPERATIONAL APPROVAL PROCESS
7.1 Part 91 Operators. A Letter of Authorization (LOA) is not required for Title 14 of the Code of Federal Regulations (14 CFR) part 91 operators (other than part 91 subpart K (part 91K)) except for oceanic operations (see Appendices E, F, and G) or if required in foreign airspace. Part 91 operators (other than part 91K) should comply with the aircraft eligibility and operational guidance in this advisory circular (AC).
7.2 Operational Authorization. To obtain operational authorization, aircraft eligibility must be determined in accordance with the applicable appendix of this AC. Operational authorizations issued under a previous version of this AC or other canceled ACs does not need to be reissued or reevaluated.
Note: Previous approvals under FAA Order 8400.12C, Required Navigation Performance 10 (RNP 10) Operational Authorization, and FAA Order 8400.33, Procedures for Obtaining Authorization for Required Navigation Performance 4 (RNP-4) Oceanic and Remote Area Operations, are still valid for these operations.
Operators must ensure their operations remain consistent with the performance and functional requirements of this AC.
7.3 Parts 91K, 121, 125, 129, and 135 Operators. Title 14 CFR parts 91K, 121, 125, 129, and 135 operators receive approval to fly RNP operations as described in this AC via operations specifications (OpSpecs), management specifications (MSpecs), or LOAs as follows:
• OpSpec/MSpec/optional LOA, paragraph C063, Area Navigation (RNAV) and Required Navigation Performance (RNP) Terminal Operations;
• OpSpec/MSpec, paragraph B035, Class 1 Navigation in U.S. Class A Airspace Using Area or Long-Range Navigation Systems;
• OpSpec/MSpec/LOA (to include Part 91 operators), paragraph B036, Oceanic and Remote Continental Navigation Using Multiple Long-Range Navigation Systems (M-LRNS); or
• Helicopter Specification (HSpec)/LOA, paragraph H123, Class I Navigation Using Area or Long-Range Navigation Systems with Wide Area Augmentation System (WAAS) for Rotorcraft Required Navigation Performance (RNP) 0.3 En Route and Terminal Operations.
Note: This AC only addresses the navigation equipment and operating requirements for these operations. The pilot and operator, as applicable, must comply with all requirements for the operation. Those requirements are specified in 14 CFR for all U.S. operators, and may be augmented by additional requirements for operations outside of the United States as specified in other documents, such as the Aeronautical Information Publications (AIP) and the International Civil Aviation Organization (ICAO) Doc 7030, Regional Supplementary Procedures (SUPPS).