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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.
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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).
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7.4 Preapplication Meeting. Certificate holders, operators, and program managers should schedule a preapplication meeting with the responsible Flight Standards office. This meeting allows the operator an opportunity to discuss the requirements for operational approval.
7.5 Multiple OpSpecs/MSpecs/LOAs. The operator should consolidate all applications for relevant RNP OpSpecs, MSpecs, or LOAs as appropriate per the operator’s present/future operational plans and capabilities (see Chapter 12, Bundling Concept).
7.5.1 Application. All operators seeking an initial approval should provide relevant documentation in support of the following areas/topics:
1. Evidence of aircraft eligibility, Note: This may be documented in manufacturer documentation (e.g., Service Letters (SL), etc.). Airplane Flight Manual (AFM) entries are not required provided the Federal Aviation Administration (FAA) accepts the manufacturer’s documentation.
2. Establishment of operating procedures for the RNP system,
3. Control of those procedures through the operations manual (as required),
4. Identification of flightcrew training requirements, and
5. Control of process for updating the navigation database.
7.5.2 Amendments. Operators who hold an approval and propose to amend due to a change in equipment or operating procedures should provide appropriate evidence that the change does not affect compliance.
8-1 CHAPTER 8. OPERATOR RESPONSIBILITIES
8.1 Operational Manuals and Checklists. Title 14 of the Code of Federal Regulations (14 CFR) part 91 operators should use relevant Airplane Flight Manuals (AFM) and checklists. Operations manuals and checklists for 14 CFR parts 91 subpart K (part 91K), 121, 125, 129, and 135 operators must address information/guidance on the standard operating procedures (SOP) detailed in Appendices A through I (as appropriate). The appropriate manuals should also contain navigation operating instructions and contingency procedures.
8.2 Training Documentation.
8.2.1 Part 91 Operator Training. Part 91 operators should be knowledgeable with the procedures and operations associated with the use of Required Navigation Performance (RNP) systems.
8.2.2 Parts 91K, 121, 125, and 135 Operator Training. Parts 91K, 121, 125, and 135 operators should have a training program addressing the operational practices, procedures and training items related to RNP operations (e.g., initial, upgrade, or recurrent training for flightcrew, operational control personnel, and maintenance personnel).
Note: A separate training program is not required if RNP training is integrated in the current training program. However, the applicant must identify the training elements from this advisory circular (AC) within the existing training program.
8.3 Minimum Equipment List (MEL) Considerations. If an MEL is required, it must include any revisions necessary to address RNP flight operations. These provisions must be approved. Operators must adjust the MEL, or equivalent, and specify the required dispatch conditions.
8.4 Pilot Knowledge/Training. Parts 91K, 121, 125, and 135 operators should maintain training syllabi (e.g., initial, upgrade, recurrent) and other appropriate materials that include operational practices and procedures. Training for other personnel must be included where appropriate (e.g., operational control personnel, maintenance).
8.4.1 Flightcrew Training. Parts 91K, 121, 125, and 135 operators should ensure their programs contain training for flightcrews on equipment requirements, normal and non-normal operations and flight procedures, and limits of their RNP navigation capability.
8.4.2 RNP Authorization Requests. Parts 91K, 121, 125, 129, and 135 operators requesting an RNP authorization must ensure that crewmembers are knowledgeable on the material contained in this AC. Training “acceptable” to the Federal Aviation Administration (FAA) is not a prerequisite for issuing an RNP authorization.
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8.4.3 Pilot Knowledge. Pilots must be familiar with the following:
1. The information in this AC, as applicable;
2. The meaning and proper use of aircraft equipment/navigation capability codes used on the flight plan;
3. Procedure characteristics as determined from chart depiction and textual description;
4. Depiction of waypoint types (flyover and flyby) as well as associated aircraft flightpaths;
5. A waypoint may be a flyover in one procedure and the same waypoint may also be a flyby in another procedure;
6. Required equipment for RNP operations;
7. Aircraft automation, mode annunciations, changes, alerts, interactions, reversions, and degradations;
8. Functional integration with other aircraft systems;
9. Meaning of route discontinuities and appropriate flightcrew procedures;
10. Types of navigation sensors used by the RNP system and their annunciations;
11. Turn anticipation with consideration to speed and altitude effects;
12. Interpretation of electronic displays and symbols;
13. Understanding the operational conditions used to support RNP operations
(e.g., appropriate selection of course deviation indicator (CDI) scaling (lateral deviation display scaling));
14. If applicable, the importance of maintaining the published path and maximum airspeeds while performing RNP operations with Radius to Fix (RF) legs;
15. Depiction of path terminators, associated aircraft flightpaths, altitude, and speed restrictions;
16. Monitoring procedures for each phase of flight (e.g., monitor PROG or LEGS page);
17. Automatic and/or manual setting of the required RNP value;
18. Understanding of the navigation equipment regarding lateral and vertical capture from an RNP routing to an instrument landing system (ILS) or Ground Based Augmentation System (GBAS) Landing System (GLS);
19. Awareness of possible false vertical and lateral captures during a transition on an ILS capture;
20. Know how offsets are applied, the functionality of their particular navigation system and the need to advise air traffic control (ATC) if this functionality is not available;
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21. Operator-recommended automation use for phase of flight and workload, including methods to minimize cross-track (XTK) error to maintain route centerline;
22. Receiver/transmitter (R/T) phraseology for RNP applications;
23. Flightcrew contingency procedures for a loss of RNP capability; and
24. Understanding the performance requirement to couple the autopilot (AP)/flight director (FD) to the navigation system’s lateral guidance on RNP procedures, if required.
Note: Operators are encouraged to use manufacturer recommended training and operating procedures.
8.4.4 Pilot Knowledge and Actions. Pilots must have adequate knowledge to perform the following actions if required by navigation specification(s) (Nav Spec(s)):
1. Verify currency and integrity of aircraft navigation data;
2. If applicable, obtain a receiver autonomous integrity monitoring (RAIM) prediction for the planned RNP operation;
3. Verify successful completion of RNP system self-tests;
4. Initialize navigation system position;
5. Retrieve and fly an RNP procedure (e.g., Standard Instrument Departure (SID) or a Standard Terminal Arrival (STAR) with appropriate transition);
6. Adhere to speed and/or altitude constraints associated with RNP operations;
7. Select the appropriate STAR or SID for the active runway in use and be familiar with procedures to deal with a runway change;
8. Verify waypoints and flight plan programming;
9. Perform a manual or automatic runway update (with takeoff point shift for Inertial Reference Units (IRU) only);
10. Fly direct to a waypoint;
11. Fly a course/track to a waypoint;
12. Intercept a course/track;
13. Fly vectors, and rejoin an RNP route/procedure from the ‘heading’ mode;
14. Selecting/arming the navigation system for an ILS or GLS transition;
15. Insert and delete route discontinuity;
16. Remove and reselect navigation sensor input;
17. When required, confirm exclusion of a specific navigation aid or navigation aid type (distance measuring equipment (DME) and very high frequency omni-directional range (VOR) only);
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18. Change arrival airport and alternate airport;
19. Verify the RNP value set in the flight management system (FMS) matches the equipment capability and authorizations as annotated in the flight plan; and
20. Perform parallel offset function if capability exists.
8.5 Operation, Procedure, or Route Selection. The equipment should not permit the flightcrew to select an operation, procedure (instrument approach procedure (IAP), SID, or STAR) or route that is not supported by the equipment, either manually or automatically (e.g., a procedure is not supported if it incorporates a RF leg or a fixed radius transition (FRT) and the equipment does not provide RF leg or FRT capability).
The system should also restrict pilot access to procedures requiring RF leg capability or FRT if the system can select the procedure, but the aircraft is not otherwise equipped
(e.g., the aircraft does not have the required roll steering AP or FD installed).
Note: Equipment manufacturers and airworthiness applicants should refer to AC 20-138( ), Chapter 6, Equipment Performance - RNAV Multi-Sensor Equipment.