Appendix 3 entire procedure and should confirm the path is flyable, does not contain any lateral or vertical discontinuities, and is consistent with the published procedure.
4. Database Updates.
a. Re-Confirm Data Accuracy. Before using an updated NDB (e.g., 28-day update) the operator must ensure the RNP AR approach data contained in that update remains within the tolerances prescribed in subparagraph 3a when compared to the government source data. If the operator finds a data parameter to exceed prescribed tolerances, he or she should consult with the appropriate navigation data supplier to resolve the discrepancy prior to using the approach procedure. Resolve discrepancies by correcting the error within the current cycle, removal of the procedure from the database, or potentially through operational mitigations approved by the FAA until the procedure data can be corrected.
b. Methodology. The method by which an operator conducts this recurring data comparison is optional, subject to the approval of the principal operations inspector (POI) or Flight Standards District Office (FSDO). One acceptable method is to establish a reference database, sometimes referred to as a “golden database,” containing known, validated approach data, and comparing data from subsequent navigation updates against this reference data. Some FMS suppliers provide automated tools, which enable a quick comparison of data parameters between databases and alert to any changes or differences. Operators may also choose to compare the navigation data contained in the updated database directly against the government source data. Regardless of the method used, operators must assure the integrity of the validated navigation data at each update cycle.
NOTE: An operator should be particularly attentive to discrepancies when updates coincide with a change to the data supplier’s packing software. This software is used to format the navigation data into code readable by aircraft avionics.
5. Data Suppliers. As a minimum, data suppliers must have a Letter of Acceptance for processing navigation data in accordance with AC 20-153, Acceptance of Data Processes and Associated Navigation Databases. A Letter of Acceptance recognizes the data supplier as one whose data quality, integrity, and quality management practices are consistent with the criteria of RTCA/DO-200A. The aircraft operator’s supplier (e.g., FMS company) must have a Type 2 Letter of Acceptance. Those entities providing data to the aircraft operator’s supplier likewise must possess either a Type 1 or Type 2 Letter of Acceptance.
6. Aircraft Modifications. If a manufacturer modifies an aircraft system required for RNP AR operations (e.g., software or hardware change), the operator must, before flying any RNP AR procedures in IMC, confirm the aircraft’s ability to fly RNP AR procedures as published with the modified aircraft system(s). The operator should examine a number of RNP AR procedures in its NDB for this flyability check. Use the criteria described in subparagraph 3b to perform this check.
Appendix 3 Page 3 (and 4) NOTE: If the manufacturer documents that the modification has no effect on the NDB or path computation, the operator need not perform this additional confirmation.
7. Recurrent Audits. The processes identified in this appendix for validating and updating RNP AR instrument approaches in NDBs are subject to recurrent FAA audits. The operator’s processes, as well as those performed by any outside entity contracted to provide NDB services, are subject to audit by the FAA. Additionally, operators are expected to conduct their own recurrent audits of entities with whom they contract to provide NDB services described in this appendix.
Appendix 4 APPENDIX 4. OPERATIONAL CONSIDERATIONS
1. General. This appendix provides guidance on the conduct of RNP AR approach operations.
In addition to observing the guidance contained herein, the operator must also continue to ensure its flightcrews comply with general RNAV operating requirements, check Notices to Airmen (NOTAM), determine availability of Navigational Aids (NAVAID), and confirm airworthiness of aircraft systems.
2. Preflight Considerations.
a. Minimum Equipment List (MEL). Operator’s MEL should address the equipment requirements for RNP AR instrument approaches. Guidance related to these equipment requirements is available from the aircraft manufacturer and Appendix 2 to this AC. The required equipment may depend on the intended RNP value and whether the missed approach requires RNP less than 1.0.
b. Class A Terrain Awareness Warning System (TAWS). An operable TAWS is required for all RNP AR procedures. The TAWS should use altitude that is compensated for local pressure and temperature effects (e.g., corrected barometric and Global Navigation Satellite System (GNSS) altitude), and include significant terrain and obstacle data.
c. Autopilot and Flight Director (FD). RNP AR procedures with RNP values less than
0.3, or with radius to fix (RF) legs, require the use of autopilot or FD driven by the RNAV system in all cases. The autopilot/FD must operate with suitable accuracy to track the lateral and vertical paths required by the RNP AR procedure.
d. RNP Prediction. The operator must have a predictive performance capability, which can forecast if the specified RNP value will be available at the time and location of a desired RNP AR operation. This capability can be a ground service and need not be resident in the aircraft’s avionics equipment. The operator must establish procedures requiring use of this capability as both a preflight dispatch tool and as a flight-following tool in the event of reported failures.
(1) This predictive capability must account for known and predicted outages of GNSS satellites or other impacts on the aircraft navigation system. The prediction program should not use a mask angle below 5 degrees, as operational experience indicates that satellite signals at low elevations are not reliable. The prediction must use the actual GNSS constellation, and when equipped, the GNSS augmentations with the algorithm identical to or more conservative than that used in the actual equipment. The RNP prediction must show the horizontal protection level (HPL) is less than the required RNP value. For RNP AR approaches with high terrain, use a mask angle appropriate to the terrain.
(2) RNP AR procedures require GNSS updating. Therefore, there is no RNP prediction associated with distance measuring equipment (DME)/DME or very high frequency omni-directional range station (VOR)/DME updating of the aircraft’s RNAV system.
Appendix 4
e. NAVAID Exclusion. The operator must establish procedures to exclude NAVAID facilities (e.g., DMEs, VORs, localizers) in accordance with NOTAMs. Internal avionics reasonableness checks may not be adequate for RNP AR operations.
f. Navigation Database (NDB) Currency. During system initialization, pilots must confirm the NDB is current. NDBs are expected to be current for the duration of the flight. If the Aeronautic Information Regulation and Control (AIRAC) cycle will change during flight, operators must establish procedures to ensure the accuracy of navigation data, including suitability of navigation facilities used to define the routes and procedures for flight.
Traditionally, this has been accomplished by verifying electronic data against paper products.
One acceptable means is to compare aeronautical charts (new and old) to verify navigation fixes prior to dispatch. If an amended chart is published for the procedure, you must not perform the RNP AR approach with the expired NDB.
3. In-Flight Considerations.
a. Modification of Flight Plan. Pilots are not authorized to fly an RNP AR procedure unless it is retrievable by the procedure name from the aircraft NDB and conforms to the charted procedure. You must not modify the lateral path, with the exception of going direct to a fix, as long as that fix is prior to the final approach fix (FAF) and does not immediately precede a RF leg. For example, referring to Figures 1 or 2 of Appendix 1, a pilot could not accept a vector to go direct to either DEMGE or SKYKO waypoints, nor to the DMIVZ FAF. The only other authorized modification to the loaded procedure is a change of altitude and/or airspeed waypoint constraints on the initial, intermediate, or missed approach segments (e.g., to comply with an air traffic control (ATC) clearance/instruction).
b. Required List of Equipment. The flightcrew must have a readily accessible list of equipment required for conducting RNP AR approaches, as well as methods to address in-flight equipment failures that would prohibit RNP AR approaches (e.g., a quick reference handbook).
c. RNP Management. The flightcrew must ensure the navigation system uses the appropriate RNP values throughout the approach. If multiple lines of minima associated with different RNP values are shown on the approach chart, the crew must confirm the desired RNP value is entered in the RNAV system. If the navigation system does not extract and set the RNP value from the onboard NDB for each leg of the procedure, the flightcrew must ensure the smallest RNP value required to complete the approach or the missed approach is selected before initiating the approach. On approaches with multiple initial approach fixes (IAF), the approach chart may specify an RNP value for each IAF.
d. Sensor Updating.
(1) RNP AR instrument procedures require GNSS performance. If at any time GNSS updating is lost and the navigation system does not have the performance to continue the approach, (i.e., unable to comply with the current RNP value) the flightcrew must abandon the RNP AR approach unless visual conditions exist between the aircraft and the runway of intended landing.
Appendix 4
(2) Except where specifically designated on a procedure as “Not Authorized,” you may use DME/DME-updating as a reversionary mode during the RNP AR approach or missed approach when:
(a) The navigation system has the performance to continue the procedure, and
(b) An assessment of the DME ground infrastructure has been accomplished.
(3) VOR updating is not authorized on RNP AR approaches.
e. Approach Procedure Confirmation. The flightcrew must confirm the correct procedure has been selected. This process includes confirmation of the waypoint sequence, reasonableness of track angles and distances, and any other parameters that can be altered by the pilot, such as altitude or speed constraints. Do not use a RNP AR procedure if validity of the NDB is in doubt.
You must use a navigation system textual display or map display for this procedure confirmation.
f. Track Deviation Monitoring. Pilots must use a lateral deviation indicator, FD and/or autopilot in LNAV mode on RNP AR approach procedures. Pilots of aircraft with a lateral deviation indicator must ensure the lateral deviation indicator scaling (full-scale deflection) is suitable for the navigation accuracy associated with the various segments of the RNP AR approach procedure. Pilots are expected to maintain procedure centerlines, as depicted by onboard lateral deviation indicators and/or flight guidance, during all RNP AR operations unless authorized to deviate by ATC or under emergency conditions. For normal operations, pilots should limit cross-track error/deviation (the difference between the RNP system computed path and the aircraft position relative to the path) to +/- one half the navigation accuracy associated with the procedure segment. Brief lateral deviations from this standard (e.g., overshoots or undershoots) during and immediately after turns, up to a maximum of 1 times the navigation accuracy of the procedure segment, are allowable.
(1) The vertical deviation must be within 75 feet during the FAS. Monitor vertical deviation above and below the glide path. While being above the glide path provides margin against obstacles on the final approach, it can result in a go-around decision closer to the runway and reduce the margin against obstacles in the missed approach.
(2) Pilots must execute a missed approach if the lateral deviation exceeds 1xRNP or the vertical deviation exceeds 75 feet, unless the pilot has acquired the visual references required to continue the approach to the intended runway.
(3) Some aircraft navigation displays do not incorporate lateral and vertical deviation indications, scaled for each RNP AR approach operation, in the primary optimum field of view (FOV). Where a moving map, low–resolution vertical deviation indicator (VDI) or numeric display of deviations are to be used, flightcrew training and procedures must ensure the effectiveness of these displays. Typically this involves demonstration of the procedure with a number of trained crews and inclusion of this monitoring procedure in the recurrent RNP AR approach training program.
Appendix 4
(4) For aircraft that use a course deviation indicator (CDI) for lateral path tracking, the Aircraft Flight Manual (AFM) or aircraft qualification guidance should state which navigation accuracy and operations the aircraft supports and the operational effects on the CDI scale. The flightcrew must know the CDI full-scale deflection value. The avionics may automatically set the CDI scale (dependent on phase of flight) or the flightcrew may manually set the scale. If the flightcrew manually selects the CDI scale, the operator must have procedures and training in place to ensure the selected CDI scale is appropriate for the intended RNP operation. The deviation limit must be readily apparent given the scale (e.g., full-scale deflection).
g. System Crosscheck. For approaches with RNP values less than 0.3, the flightcrew must crosscheck the lateral and vertical guidance provided by the navigation system with other available data and displays provided by an independent means (e.g., TAWS, weather radar, etc.).
NOTE: This crosscheck may not be necessary if the aircraft meets the requirements of Appendix 2, subparagraphs 2d and 3e. Use of GPS/SBAS vertical guidance precludes the need for independent monitoring.
h. Procedures with RF Legs. An RNP AR procedure may include an RF leg. As not all aircraft have this capability, flightcrews must know if they can conduct these procedures. When flying an RF leg, flightcrew compliance with the desired path is essential to maintain the intended ground track.
(1) If initiating a go-around during or shortly after the RF leg, the flightcrew must be aware of the importance of maintaining the published path as closely as possible. Operators must develop specific procedures to ensure maintenance of the RNP AR ground track in those aircraft which do not remain in LNAV upon initiation of a go-around.
(2) Pilots must not exceed the maximum airspeeds shown in Table 1 throughout the RF leg segment. For example, a Category (CAT) C aircraft must slow to 140 knots indicated airspeed (KIAS) at the FAF or may fly as fast as 165 KIAS if using CAT D minima. A missed approach prior to Decision Altitude (DA) requires maintaining the segment speed to the DA and then observing any speed limitations specified for the missed approach segment.
Appendix 4 TABLE 1. MAXIMUM AIRSPEEDS THROUGHOUT THE RADIUS TO A FIX
LEG SEGMENT Indicated Airspeed (Knots) Indicated Airspeed by Aircraft CAT Segment Cat A Cat B Cat C Cat D Cat E Initial & Intermediate (IAF to FAF) 150 150 250 250 250 Final (FAF to DA) 90 120 140 165 As Specified Missed Approach (DA to missed approach holding point) 110 150 250 265 As Specified
i. Temperature Compensation. For aircraft equipped with temperature compensation in accordance with Appendix 2, subparagraph 3a(7), flightcrews may disregard the temperature limits on RNP AR procedures if the operator provides pilot training on the use of the temperature compensation function.
NOTE: Since the charted temperature limits ensure obstacle clearance solely in the FAS, and since temperature compensation only affects the vertical guidance, the pilot may need to manually adjust the minimum altitude on the initial and intermediate approach segments and the DA. Pilots must coordinate with ATC prior to use of temperature compensation in order to prevent loss of aircraft separation.
j. Altimeter Crosscheck. The flightcrew must complete an altimetry crosscheck ensuring that both pilots’ altimeters agree within ±100 feet not later than the FAF after receiving the current local altimeter setting at the airport of intended landing. Do not continue the procedure if the altimetry crosscheck fails.
NOTE: This operational crosscheck is not necessary if the aircraft automatically compares the altitudes to within 100 feet (refer to Appendix 2, subparagraph 3d(14)).
k. Altimeter Setting. Due to the reduced obstruction clearance inherent in RNP AR instrument procedures, the flightcrew must verify the current local altimeter at the airport of intended landing is set not later than the FAF. Remote altimeter settings are not allowed.
l. Non-Standard Climb Gradient. When planning to use the DA associated with a non-standard missed approach climb gradient, the operator must ensure the aircraft will be able to comply with the published climb gradient for the planned aircraft loading, atmospheric conditions and operating procedures.
m. Engine-Out Procedures. RNP AR procedures are based on normal operations. However, you can find guidance for developing engine-out extraction procedures in AC 120-91, Airport Obstacle Analysis.
Appendix 4
n. Go-Around or Missed Approach. There are two types of missed approach procedures:
RNP 1.0 and RNP less than 1.0.
(1) RNP AR missed approaches are typically designed to require RNP 1.0 and no additional actions on the part of the flightcrew. The missed approach portion of these procedures is similar to a missed approach on an RNAV Global Positioning System (GPS) approach.
(2) If the MAS requires an RNP value less than 1.0, the approach chart will include the following note: “Missed approach requires RNP less than 1.0.” In order to fly such an RNP AR procedure, aircraft equipage and operating procedures must meet the criteria of Appendix 2, paragraph 6.
(3) In many aircraft, activating Take-off/Go-around (TOGA) causes a change in LNAV.
Activating TOGA may also disengage the autopilot and FD from LNAV guidance, with the FD reverting to track-hold derived from the inertial system. LNAV guidance to the autopilot and FD should be re-engaged as quickly as possible.
(4) Flightcrew procedures and training must address the impact on navigation capability and flight guidance if the pilot initiates a go-around while the aircraft is in a turn (e.g., on an RF leg).
o. Contingency Procedures.
(1) Provide guidance to the flightcrew on how to assess and react to en route failures of RNP AR approach required equipment.
(2) The operator’s contingency procedures must also address at least the following conditions occurring during the RNP AR approach:
(a) Failure of RNP system components, including those affecting lateral and vertical path tracking performance (e.g., failures of a GPS sensor, the FD, or automatic pilot); and
(b) Loss of navigation signal-in-space (loss or degradation of external signal).
Appendix 5
Page 1 APPENDIX 5. TRAINING
1. Introduction. The operator must provide training, as outlined here for pilots and dispatchers, in the flight planning and operation of RNP AR approach procedures. This training must provide sufficient detail on the aircraft’s navigation and flight control systems to enable pilots to identify issues affecting the RNP capability of the aircraft and take appropriate action. Required training must include both knowledge and skill assessments of pilot and dispatcher duties. An individual must have completed the appropriate training before engaging in RNP AR operations. A thorough understanding of the operational procedures and best practices is critical to the safe operation of aircraft during RNP AR operations. A combination of instructional media may be used to satisfy these training requirements.
a. Pilot Training.
(1) Each operator is responsible for the tr aining of pilots for the specific RNP AR operations conducted. Operators must include RNP AR regulatory requirements and procedures in their flight operations and training manuals (as applicable). This material must cover pertinent aspects of the operator’s RNP AR operations including the applicable FAA authorization; i.e., operations specifications (OpSpecs), management specifications (MSpecs), or letter of authorization (LOA).
(2) Flight training must be re presentative of the type of RNP AR procedures the operator will conduct. Operators that use Advanced Qualification Programs (AQP) may conduct evaluations in Line-Oriented Flight Training (LOFT) scenarios, Selected Event Training (SET) scenarios, or a combination of both. The operator may conduct required flight training in flight simulation training devices (FSTD) and other enhanced training devices as long as these training mediums accurately replicate the operator’s equipment and RNP AR approach operations. The FSTDs must be approved for RNP AR training.
b. Parts 91K, 121, 125, and 135 Pilot Qualification Training.
(1) Operators must address initial RNP AR training and qualifications during initial, transition, upgrade, recurrent, differences, or stand-alone training and qualification programs in a respective qualification category. The qualification standards assess each pilot’s ability to properly understand and use RNP AR approach procedures. The operator must also develop recurrent qualification standards to ensure its pilots maintain appropriate RNP AR knowledge and skills.
(2) Operators may address RNP AR operation topi cs separately or integrate them with other curriculum elements. For example, an RNP AR pilot qualification may key on a specific aircraft during transition, upgrade, or differences courses. General training may also address RNP AR qualification (e.g., during recurrent training or checking events such as recurrent proficiency check (PC)/proficiency training (PT), line-oriented evaluation, or Special Purpose Operational Training (SPOT)).
(3) Operators desiring to re ceive credit for previously-conducted RNP training
(e.g., Special RNP Approach Procedures) against the requirements specified in this appendix
Appendix 5 must receive specific authorization from their principal operations inspector (POI) or equivalent regulatory authority. In addition to the current RNP training program the operator will need to provide training on the differences between their existing RNP operations and RNP AR requirements.
c. Flight Dispatcher Training. Dispatchers must complete appropriate training before engaging in RNP AR operations. This training must cover all pertinent aspects of the operator’s RNP AR operations including:
(1) Understanding of regulatory requirements and dispatch procedures pertinent to the different types of RNP AR procedures performed, as well as the applicable FAA authorization (OpSpecs, MSpecs, or LOA);
(2) The ability to determine GPS availability and accuracy for RNP AR procedures at the destination, alternate, and en route alternates for the expected time of use; and
(3) Understanding aircraft equipment capabilities and the effects of minimum equipment list (MEL) requirements, aircraft performance, and navigation signal availability on RNP AR capabilities.
2. Pilot Ground Training. Initial RNP AR ground training must address the material listed in subparagraphs 2a through 2c. For recurrent RNP AR training, the curriculum need only address new, revised, or emphasized items.
a. Theory/Knowledge/Definitions. RNP AR ground training must cover RNP AR systems, operation, classifications, and limitations. Training must include general knowledge and operational application of RNP AR IAP, and address the following specific elements:
(1) Definitions of RNAV (RNP), RNAV (GPS), RNP, RNP AR, containment, and the differences between RNAV and RNP;
(2) RNP AR approach charting, to include applicable lines of minima, temperature limitations, non-standard climb gradients, RF legs, speed restrictions, and missed approach RNP requirements;
(3) How to determine if specific RNP values will be available at the destination, alternate, and en route alternates, for the expected time of use;
(4) The different components contributing to Total System Error (i.e., path steering error, path definition error, and position estimation error) and their characteristics;
(5) Compare flight performance of the aircraft to the required flight performance for the RNP AR procedure to be flown, including speed limitations and any non-standard climb gradients required;
(6) Alerts that may occur from the loading and use of improper RNP values for a desired segment of an RNP AR procedure;
Appendix 5
(7) Performance and/or equipment requirements applicable to a specified RNP value; e.g., requirement to use autopilot or flight director below a specified RNP value;
(8) When and how to terminate RNP navigation and transfer to traditional navigation
(e.g., due to loss of RNP and/or required equipment);
(9) Operational limitations if Actual Navigation Performance (ANP) degrades or RNP is lost prior to or during any portion of the approach; and
(10) How bank angle restrictions, wind, and groundspeed impact the ability to remain on the course centerline, particularly on an RF leg.
b. Pilot Procedures. Training should encompass normal and abnormal operating procedures, responses to equipment annunciations, failures, alerts, and any limitations on RNP operation. Training must also address contingency procedures for loss or degradation of RNP capability. The flight operations manuals approved for use (e.g., Flight Operations Manual (FOM) or pilot’s operating handbook (POH)) should contain this information. Training must address the following elements:
(1) Review of modifications to company documents for RNP AR operations, such as Company Flight Manual (CFM), FOM, etc., as well as understanding which checklist items need to be accomplished prior to and during RNP AR approach procedures.
(2) Briefings for all RNP AR procedures including RNP approach and missed approach profiles and normal procedures. Training should address any additional briefings or review cards that may be required or available prior to commencing an RNP AR procedure.
(3) Compliance with charted airspeed limitations. In the absence of charted airspeed limitations, the maximum airspeeds shown in Appendix 4, Table 1 apply for all RF legs. These speed restrictions cannot be waived by air traffic control (ATC).
(4) Understanding of and compliance with the parameters associated with an RNP AR approach, such as ANP versus RNP, cross track error, etc., as well as factors that affect aircraft ability to maintain lateral and vertical path and how to correct for deviations from path.
(5) RNP AR symbology, operation, controls, and displays, as well as equipment or software differences between aircraft as applicable.
(6) Appropriate responses to annunciations, cautions, alerts, and limitations.
(7) Programming and operating the flight management computer (FMC), autopilot, auto throttle/auto thrust, radar, GPS, inertial reference unit (IRU), electronic flight instrument system (EFIS) (including moving maps), and Terrain Awareness Warning Systems (TAWS) in support of RNP AR procedures.
(8) Procedures used to verify that the FMC database and RNP AR approach procedures are current and contain required navigation data.
Appendix 5
(9) How to select RNP values for RNP AR approaches, and for different phases of flight (if required).
(10) Use of temperature compensation, if applicable.
(11) MEL operating provisions applicable to RNP AR approaches.
(12) Procedures for verifying current local altimeter is set before beginning an RNP AR procedure, including any operational limitations associated with the source(s) for the altimeter setting and the latency of checking and setting the altimeters approaching the FAF.
(13) Events that trigger a missed approach, including deviations from path, as well as issues applicable to the missed approach; e.g., lateral steering mode following initiation of a missed approach during a turn or shortly after rollout, timely re-engagement of lateral navigation (LNAV), and the critical importance of maintaining track within 1xRNP between initiation of the missed approach and re-engagement of LNAV.
(14) Impact of GPS loss during an approach and understanding the performance issues and limitations associated with reversion to radio updating. Also, how to control the navigation updating modes related to RNP AR operations.
(15) Pilots should understand the implications of interrupted approaches in the radar environment; e.g., being vectored off then back on the approach. Consideration should also be given to the non-radar environment, where pilots may be required to hold as published and then resume the approach. Pilots should understand how to resume both lateral and vertical paths, as well as the need to inform ATC immediately when the performance of the aircraft will no longer support RNP AR operations.
c. Abnormals/Failures. The operator’s RNP AR training must address the following:
(1) Pilot contingency procedures for a loss of RNP capability during an approach.
Training should emphasize contingency actions that achieve separation from terrain and obstacles. The operator should tailor these contingency procedures to the RNP AR procedures they will fly.
(2) The navigation sensors which form the basis for their RNP operations, and how to assess the impact of failure of any avionics or a known loss of external system(s).
(3) Ability to recognize, evaluate, and take appropriate action in response to any system or instrument failures that affect RNP operations prior to or during an RNP AR approach.
Examples of failures that could degrade the RNP capability of the aircraft include:
(a) Autopilot failure,
(b) Autothrottle/Autothrust failure,
(c) GPS failure,