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.
9-1 CHAPTER 9. FLIGHT PLANNING
9.1 Required Navigation Performance (RNP) Flight Planning Requirements. Pilots and operators must use all available information in planning their flight, to ensure suitable navigation performance.
Note: Oceanic and remote continental RNP operations have unique flight planning requirements to ensure reliable navigation if a Global Positioning System (GPS) satellite fails.
9.1.1 RNP 2, RNP 4, and RNP 10. The specific requirements for RNP 2, RNP 4, and RNP 10 can be found in:
• Appendix E, Qualification Criteria for Required Navigation Performance (RNP) 2 Domestic, Offshore, Oceanic, and Remote Continental Operations,
• Appendix F, Qualification Criteria for Required Navigation Performance (RNP) 4 Oceanic and Remote Continental Operations, and
• Appendix G, Qualification Criteria for Required Navigation Performance (RNP) 10 Oceanic and Remote Continental Operations, respectively.
9.2 Notices to Airmen (NOTAM). All operators should review NOTAMs, as the Federal Aviation Administration (FAA) may indicate that GPS is unreliable in certain airspace and at certain times. For example, the FAA may do this in the event of interference to GPS. The FAA also provides a NOTAM service for Satellite-based Augmentation System (SBAS) (e.g., wide area augmentation system (WAAS)) receivers for all domestic RNP operations covered by this advisory circular (AC), which will identify any performance outages affecting Technical Standard Order (TSO)-C145 or TSO-C146 equipment. Operators flying aircraft equipped with SBAS do not need to conduct a preflight availability prediction for domestic RNP operations if WAAS coverage is confirmed to be available along the entire route of flight. For operations outside of the United States and using SBAS equipment, the operator should determine if the Air Navigation Service Provider (ANSP) monitors the performance of SBAS equipment or if it is appropriate to use a receiver autonomous integrity monitoring (RAIM) prediction program for the flight.
9.3 GPS Performance Prediction.
9.3.1 Equipment in Accordance with TSO-C129 or TSO-C196. If TSO-C129( ) or TSO-C196 equipment is used to solely satisfy the RNP monitoring and alerting requirement, GPS RAIM availability must be confirmed for the intended route of flight (route and time) using available GPS satellite information. Therefore, pilots should prepare to assess their capability to navigate (potentially to an alternate destination) in case of failure of Global Navigation Satellite System (GNSS) navigation.
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9.3.2 Prediction Methods. Operators may satisfy the predictive RAIM requirement through any one of the following methods:
1. Operators of large fleets of aircraft or users of flight planning programs may wish to use their own preflight availability verification tool. The operator is responsible for selecting a tool that accurately predicts the performance for their aircraft. The tool must consider the GPS satellites that are in service at the time of the prediction, and may take into account unique characteristics of the GPS receiver, aircraft integration or installation; including performance better than required in FAA standards or use of inertial information integrated into the navigation position solution. The FAA does not evaluate or approve a particular tool, but may evaluate the basis of the operator’s determination that the tool is appropriate to their aircraft, particularly if its use results in unexpected loss of RNP navigation.
2. Operators may use the FAA en route and terminal RAIM prediction:
Service Availability Prediction Tool (SAPT) (http://sapt.faa.gov). Refer to the SAPT User Guide (current edition) for specific instructions on its use;
3. Operators may use a third party interface, incorporating FAA RAIM prediction data without altering performance values, to predict RAIM outages for the aircraft’s predicted flightpath and times;
4. Operators may use the receiver’s installed RAIM prediction capability (for TSO-C129a/Class A1/B1/C1 or TSO-C196( ) equipment) to provide Nonprecision Approach (NPA) RAIM, accounting for the latest GPS constellation status (e.g., NOTAMs or Notice Advisories to Navstar Users (NANU)). Receiver NPA RAIM should be checked at airports spaced at intervals not to exceed 60 nautical miles (NM) along the Area Navigation (RNAV) 1 procedures flight track. Terminal or approach RAIM must be available at the estimated time of arrival (ETA) over each airport checked.
9.3.3 Prediction Model Parameters. The operator should use a model appropriate to their equipment, including the type of GPS receiver and the demonstrated capability to track satellites at a given mask angle. When selecting a mask angle, the operator should consider the equipment qualification, installation in the aircraft, and the effects of normal maneuvering. Aircraft are typically qualified with a five-degree mask angle, and operational experience has indicated that a two-degree mask angle can be achieved by some equipment installations. If using the SAPT, each prediction is valid for the operation within 5 minutes of the plan time and 7.5 NM of the route. The operator may wish to submit additional requests for predictions for varying times around the proposed departure time to ensure compliance at the actual departure time.
9.3.4 Flight Planning Guidance. Predictions can be used for initial flight planning as early as 72 hours prior to the planned departure. However, the operator should conduct a performance prediction as close to departure time as feasible, but with sufficient time to re-plan the flight or obtain air traffic control (ATC) prior approval in the event a segment of the flight will not be compliant. The prediction should be reevaluated if a new NOTAM identifies an unscheduled GPS satellite outage.
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9.3.5 Resolving Predicted Outages in Performance. In the event of a predicted, continuous loss of RAIM of more than 5 minutes for any part of the intended flight, the flight must be delayed, canceled, or re-routed where RAIM requirements can be met. Alternatively, the flight may be re-planned based on a different form of navigation.
9.4 Distance Measuring Equipment (DME) Flight Planning Requirements. For multisensor aircraft with operating GPS and DME/DME/Inertial Reference Unit (IRU) positioning, a RAIM check for continental operations is not required as long as DME is identified as an available navigation service for the route and critical DME’s are functioning normally. However, when planning for a Required Navigation Performance Approach (RNP APCH) (Appendix A, Qualification Criteria for Required Navigation Performance Approach (RNP APCH) Operations), a RAIM check is still required as this exception does not apply to RNP APCH operations.
9.5 Contingency Planning for Alternate Airport.
9.5.1 Alternate Airport Considerations. For the purposes of flight planning, any required alternate airport must have an available instrument approach procedure (IAP) that does not require the use of GPS. This restriction includes conducting a conventional approach at the alternate airport using a substitute means of navigation that is based upon the use of GPS. For example, these restrictions would apply when planning to use GPS equipment as a substitute means of navigation for an out-of-service very high frequency omni-directional range (VOR) that supports an instrument landing system (ILS) Missed Approach Procedure (MAP) at an alternate airport. In this case, some other approach not reliant upon the use of GPS must be available. This restriction does not apply to pilots with navigation systems meeting the requirements below.
9.5.1.1 For flight planning purposes, TSO-C129( ) and TSO-C196( ) equipped users (GPS users) whose navigation systems have fault detection and exclusion (FDE) capability, who perform a preflight RAIM prediction at the airport where the RNAV (GPS) approach will be flown, and have proper knowledge and any required training and/or approval to conduct a GPS-based IAP, may file based on a GPS-based IAP at either the destination or the alternate airport, but not at both locations. At the alternate airport, pilots may plan for applicable alternate airport weather minimums using:
1. Lateral navigation (LNAV) or circling minimum descent altitude (MDA);
2. LNAV/vertical navigation (VNAV) decision altitude (DA), if equipped with and using approved barometric vertical navigation (baro-VNAV) equipment;
3. RNP 0.3 DA on an RNAV (RNP) IAP, if they are specifically authorized users using approved baro-VNAV equipment and the pilot has verified RNP availability through an approved prediction program.
9-4 Note: If the above conditions cannot be met, any required alternate airport must have an approved IAP other than GPS that is anticipated to be operational and available at the ETA, and which the aircraft is equipped to fly.
9.5.1.2 Pilots with WAAS receivers, TSO-C145( ) or TSO-C146( ), may flight plan to use any IAP authorized for use with their WAAS avionics as the planned approach at a required alternate, with the following restrictions. When using WAAS at an alternate airport, flight planning must be based on flying the RNAV (GPS) LNAV or circling minima line, or minima on a GPS approach procedure, or conventional approach procedure with “or GPS” in the title.
Properly trained and approved, as required, TSO-C145( ) and TSO-C146( ) equipped users (WAAS users) with and using approved baro-VNAV equipment may plan for LNAV/VNAV DA at an alternate airport.
Specifically authorized WAAS users with and using approved baro-VNAV equipment may also plan for RNP 0.3 DA at the alternate airport as long as the pilot has verified RNP availability through an approved prediction program. Title 14 of the Code of Federal Regulations (14 CFR) part 91 nonprecision weather requirements must be used for planning. Upon arrival at an alternate, when the WAAS navigation system indicates that LNAV/VNAV or localizer performance with vertical guidance (LPV) service is available, then vertical guidance may be used to complete the approach using the displayed level of service.