g. Functional Requirem ents for Navigation Displays.
(1) The following navigation displays and functions are required, as installed in accordance with this AC or equivalent system installation advisory material. Navigation data, including a TO/FROM indication and a failure indicator, must be displayed on a lateral deviation display (course deviation indicator (CDI), electronic horizontal situation indicator (EHSI)) and/or a navigation map display. These must be used as primary flight instruments for aircraft navigation, for maneuver anticipation, and for failure/status/integrity indication.
(2) A non-numeric lateral deviation display (for example, CDI, EHSI), with a TO/FROM indication and a failure annunciation, used as primary flight instruments for aircraft navigation, for maneuver anticipation, and for failure/status/integrity indication, should have the following attributes:
(a) The displays must be visible to the pilot and located in the primary field of view.
(b) The lateral deviation display scaling should agree with any alerting and annunciation limits, if implemented.
(c) The lateral deviation display must have a full-scale deflection suitable for the current phase of flight and must be based on the TSE requirement. Scaling of ± 1 NM for the initial, intermediate, and missed approach segments and ±0.3 NM for the final segment is acceptable.
(d) The display scaling may be set automatically by default logic or set to a value obtained from a navigation database. The full-scale deflection value must be known or must be available for display to the pilot commensurate with approach values.
(e) The lateral deviation display must be automatically slaved to the RNP computed path. It is recommended that the course selector of the deviation display be automatically slewed to the RNP computed path.
Note: This does not apply for installations where an electronic map display contains a graphical display of the flight path and path deviation.
(f) As an alternate means, a navigation map display must provide equivalent functionality to a lateral deviation display with appropriate map scales (scaling may be set manually by the pilot). To be approved as an alternative means, the navigation map display must be shown to meet the TSE requirements and be located in the primary field of view.
h. System Capabilities.
The following system capabilities are required as a minimum:
(1) The capability to continuously display to the pilot flying, on the primary flight instruments for aircraft navigation (primary navigation display), the RNP computed desired 46
path and a ircraft position relative to the path. For operations where the required minimum flightcrew is two pilots, a means for the pilot not flying (pilot monitoring) must also be provided to verify the desired path and the aircraft position relative to the path.
(2) A navigation database, containing current navigation data officially promulgated for civil aviation, which can be updated in accordance with the aeronautical information regulation and control (AIRAC) cycle. The stored resolution of the data must be sufficient to achieve the required track keeping accuracy. The database must be protected against pilot modification of the stored data.
(3) The means to display the navigation data validity period to the pilot.
(4) The means to retrieve and display data stored in the navigation database relating to individual waypoints and navigation aids, to enable the pilot to verify the route to be flown.
(5) Capability to load from the database into the RNP system the whole approach to be flown. The approach must be loaded from the database, into the RNP system, by its name.
(6) The means to display the following items, either in the pilot’s primary field of view, or on a readily accessible display page:
(a) Distance between flight plan waypoints;
(b) Distance to go to the waypoint selected by the pilot;
(c) Along track distances between waypoints;
(d) Active navigation sensor type;
(e) The identification of the active (To) waypoint;
(f) The ground speed or time to the active (To) waypoint; and
(g) The distance and bearing to the active (To) waypoint.
(7) The capability to execute a “Direct to” function.
(8) The capability for automatic leg sequencing with display to the pilots.
(9) The capability to execute RNP instrument approach procedures extracted from the onboard database including the capability to execute fly-over and fly-by turns.
(10) The capability to au tomatically execute leg transitions and maintain tracks consistent with the following ARINC 424 path terminators, or their equivalent:
(a) Initial F ix (IF).
(b) Track to Fix (TF).
(c) Direct to Fix (DF).
Note 1: Path terminators are defined in ARINC Specification 424, and their application is described in more detail in RTCA/DO-236B and RTCA/ DO-201A, Standards for Aeronautical Information, dated April 19, 2000.
Note 2: Numeric values for tracks must be automatically loaded from the RNP system database.
(11) The capability to display an indication of the RNP system failure in the pilot’s primary field of view.
(12) The capability to indicate to the crew when the navigation system error (NSE) alert limit is exceeded (alert provided by the “onboard performance monitoring and alerting function”).
i. Flight Director/Autopilot.
It is recommended that the flight director (FD) and/or autopilot remain coupled for RNP approaches. If the lateral TSE cannot be demonstrated without these systems, then coupling becomes mandatory. In this instance, operating guidance must indicate that coupling to the FD and/or automatic pilot from the RNP system is mandatory for approaches.
j. Database Integrity.
The navigation database suppliers must comply with RTCA/DO-200A. A Type 2 Letter of Acceptance (LOA), issued by the appropriate regulatory authority, demonstrates compliance with this requirement. Type 2 LOAs issued prior to this AC are considered compliant.
8-4. System Eligibility and Approval for RNP Operations.
a. Introduction.
The original equipm ent manufacturer (OEM) or the holder of installation approval for the aircraft (e.g., STC holder), must demonstrate compliance with the appropriate provisions of this AC to the FAA and the approval can be documented in manufacturer documentation
(e.g., Service Letters, etc.). AFM/RFM entries are not required provided the FAA accepts the manufacturer’s documentation.
b. Eligibility for RNP Instrum ent Approach Operations.
Systems meeting the requirements in paragraph 8-2 are eligible for RNP instrument approach operations. Aircraft qualified by any revision of AC 90-101 for RNP AR are considered qualified for RNP approach operations without further examination.
c. System Eligibility for RNP Approach Operations.
(1) LNAV line of minima qualification.
(a) Stand-alone systems meeting TSO-C129(AR) Class A1 or TSO-C146(AR) Class 1, 2, or 3 meet the aircraft qualification requirements for RNP instrument approach operations using the LNAV line of minima provided the systems and IFR installations were performed in accordance with this AC.
(b) Multi-sensor systems using TSO-C129(AR) Class B1, B3, C1, or C3 sensors; TSO-C196 sensors; TSO-C145(AR) Class 1, 2, or 3 sensors; or, TSO-C161a sensors using GBAS positioning service meet the aircraft qualification requirements for RNP instrument approach operations using the LNAV line of minima, provided the installations are in accordance with this AC and the associated FMS complies with TSO-C115b.
Note: Multi-sensor systems may also have incomplete system TSO-C129(AR) Class A or TSO-C146(AR) Class Gamma approvals (see paragraphs 3-1.d and 3-2.e).
(2) LNAV/VNAV line of minima qualification.
(a) Stand-alone TSO-C146(AR) Class 2 or 3 systems meet the aircraft qualification requirements for RNP instrument approach operations using the LNAV/VNAV line of minima provided that the installations are in accordance with this AC. Systems meeting TSO-C129(AR) Class A1 with baro-VNAV can be used for RNP approaches using the LNAV/VNAV line of minima if the criteria in chapters 13 and 15 are met and the systems are installed in accordance with this AC.
(b) Multi-sensor systems using TSO-C145(AR) Class 2 or 3 sensors meet the aircraft qualification requirements for RNP instrument approach operations using the LNAV/VNAV line of minima provided that the installations are in accordance with this AC and the associated FMS complies with TSO-C115b.
Note: Multi-sensor systems may also have incomplete system TSO-C129(AR) Class A or TSO-C146(AR) Class Gamma approvals (see paragraphs 3-1.d and 3-2.e).
(c) Multi-sensor systems using TSO-C129(AR) Class B1, B3, C1, or C3 sensors with baro-VNAV; TSO-C196 sensors with baro-VNAV; or, TSO-C161a sensors using the GBAS positioning service with baro-VNAV can be used for RNP approaches using the LNAV/VNAV line of minima if the criteria in chapters 13 and 15 are met and the systems are 49
50 installed in accordance with this AC. The associated FMS must comply with TSO-C115b.
Note: Multi-sensor systems may also have incomplete system TSO-C129(AR) Class A or TSO-C146(AR) Class Gamma approvals (see paragraphs 3-1.d and 3-2.e).
Chapter 9. Equipment Performa nce - RNP Terminal.
9-1. Introduction.
This chapter provides guidance on the perform ance and functional requirements for RNP 1 operations in the terminal area. RNP Terminal terminology is used in the AC 90-105, appendix 2 title, and is synonymous with RNP 1. The equipment can be used to conduct RNP instrument departure procedures (including RNP ODPs and SIDs) and RNP STARs within the United States NAS where domestic air traffic control procedures are applied.
9-2. Aircraft and System Requirements for RNP Terminal Operations.
The notes below apply to the entire paragraph.
a. Aircraf t with a statement of compliance with the criteria in this AC in their AFM/RFM, AFMS/RFMS, POH, or the operating manual for their avionics meet the performance and functional requirements for RNP terminal operations. This presumes compliance with the operational guidance in AC 90-105.
b. Aircraft with a statement from the manufacturer documenting compliance with the criteria in this AC meet the performance and functional requirements for RNP terminal operations. These statements should include the airworthiness basis for compliance.
Compliance with the sensor requirements will have to be determined by the equipment or aircraft manufacturer while compliance with the functional requirements in this chapter may be determined by the manufacturer or by inspection by the operator, but must presume compliance with operational guidance in AC 90-105.
c. GPS stand-alone equipment should be approved in accordance with TSO-C129(AR) Class A1 or TSO-C146(AR) Class 1, 2, or 3, and meet the applicable performance and functional requirements of chapter 5 and this chapter. These systems should be installed for IFR use in accordance with this AC.
d. GPS sensors used in multi-sensor system equipment (e.g., FMS) should be approved in accordance with TSO-C129(AR) Class B or C, TSO-C196, or TSO-C145(AR) Class 1, 2, or 3 and meet the applicable performance and functional requirements of chapter 5 and this chapter. These systems should be installed for IFR use in accordance with this AC.
e. Multi-sensor systems should be approved in accordance with TSO-C115b, but may also have incomplete system TSO-C129(AR) Class A or TSO-C146(AR) Class Gamma approvals (see paragraphs 3-1.d and 3-2.e). Those systems using GPS equipment should comply with the applicable GPS equipment chapters and chapters 6, 11-13, 15, 18, 19, and 21 of this AC. These systems should also meet the performance and functionality requirements in this chapter.
f. Aircraft/equipment with approval under AC 90-100A (or later revision) to use GPS is approved under this AC for RNP 1 operations.
g. RNP aircraft with P-RNAV approval based on GPS capability m eet the functional requirements of this AC for RNP 1 operations, such as RNP DPs, RNP SIDs, and RNP STARS.
Note 1: RNP 1 operations are based on GPS positioning and, if adequate coverage is available, DME/DME/IRU.
Positioning data from other types of navigation sensors may be integrated with the GPS data provided it does not cause position errors exceeding the TSE budget.
Otherwise, means should be provided to deselect the other navigation sensor types.
Note 2: TSO-C145(AR) or TSO-C146(AR) equipment may also be authorized to conduct RNP operations in United States airspace where domestic ATC procedures are applied (Class I Navigation operations) without an airworthiness limitation for other navigation equipment on the aircraft. This authorization includes operations outside the navigational service volume of ICAO standard ground-based NAVAIDs.
9-3. System Performance Monitoring and Alerting.
a. Accuracy.
(1) The aircraft must com ply with RTCA/DO-236B, paragraph 2.1.1.
(2) During operations in airspace or on routes designated as RNP 1, the lateral TSE must be within ±1 NM for at least 95 percent of the total flight time. The along-track error must also be within ±1 NM for at least 95 percent of the total flight time. To satisfy the accuracy requirement, the 95 percent, FTE should not exceed 0.5 NM (see chapter 16).
Note: Using a lateral deviation indicator with 1 NM full-scale deflection is an acceptable means of compliance.
Using an autopilot or FD is also an acceptable means of compliance, but roll stabilization systems do not qualify.
b. Integrity.
Malfunction of the aircraft navigation equipment that causes the TSE to exceed 2 times the RNP value without annunciation is classified as a major failure condition under airworthiness regulations (i.e., 10-5 per hour).
c. Continuity.
Loss of function is classified as a minor failure condition if the operator can revert to a different navigation system and proceed to a suitable airport.
d. Perform ance Monitoring and Alerting.
The RNP system, or the RNP system and pilot in combination, must provide an alert if the accuracy requirement is not met, or if the probability that the lateral TSE exceeds 2 NM is greater than 10-5 for RNP 1 operations.
e. Path Definition.
RNP systems should provide lateral guidance so aircraft remain within the lateral boundaries of the fly-by transition area as defined in RTCA/DO-236B, paragraph 3.2.5.4.1.
f. Signal-in-Space.
If using GPS, the aircraft navigation equipment must provide an alert if the probability of signal-in-space errors causing a lateral position error greater than 2 NM exceeds 10-7 per hour for RNP 1 operations.
g. Functional Requirements of Navigation Data Displays.
(1) If using this AC as the means of compliance, then the following navigation displays and functions are required and must be installed in accordance with this AC.
(2) Navigation data, including a TO/FROM indication and a failure indicator, must be displayed on a lateral deviation display (CDI, EHSI) and/or a navigation map display.
These must be used as primary flight instruments for aircraft navigation, for maneuver anticipation, and for failure/status/integrity indication. A non-numeric lateral deviation display (for example, CDI, EHSI), with a TO/FROM indication and a failure annunciation, used as primary flight instruments for aircraft navigation, for maneuver anticipation, and for failure/status/integrity indication, should have the following attributes:
(a) The displays must be visible to the pilot and located in the primary field of view when looking forward along the flight path.
(b) The lateral deviation display scaling must agree with any alerting and annunciation limits, if implemented.
(c) The lateral deviation display must have a full-scale deflection suitable for the current phase of flight and must be based on the required total system accuracy.
(d) The display scaling may be set automatically by default logic or set to a value obtained from a navigation database. The full-scale deflection value must be known or must be available for display to the pilot commensurate with terminal area values.
(e) The lateral deviation display must be automatically slaved to the RNP computed path. It is recommended that the course selector of the deviation display be automatically slewed to the RNP computed path.
Note: This does not apply for installations where an electronic map display contains a graphical display of the flight path and path deviation.
(f) As an altern ate means, a navigation map display must give equivalent functionality to a lateral deviation display with appropriate map scales (scaling may be set manually by the pilot), and giving equivalent functionality to a lateral deviation display. To be approved as an alternative means, the navigation map display must be shown to meet the TSE requirements and be located in the primary field of view.
h. System Capabilities.
The following system capabilities are required as a minimum within any RNP 1 equipment:
(1) The capability to continuously display to the pilot flying, on the primary flight instruments for navigation of the aircraft (primary navigation display), the RNP computed desired path and aircraft position relative to the path. For operations where the required minimum flight crew is two pilots, a means for the pilot not flying must also be provided to verify the desired path and the aircraft position relative to the path.
(2) A navigation database, containing current navigation data officially promulgated for civil aviation, which can be updated in accordance with the AIRAC cycle. The stored resolution of the data must be sufficient to achieve the required track keeping accuracy.
The database must be protected against pilot modification of the stored data.
(3) The means to display the validity period of the navigation data to the pilot.
(4) The means to retrieve and display data stored in the navigation database relating to individual waypoints and navigation aids, so the pilot can verify the route to be flown.
(5) Capability to load from the database into the RNP 1 system the entire segment of the SID, ODP, or STAR to be flown.
Note: Due to variability in systems, this document defines the segment from the first occurrence of a named waypoint, track, or course to the last occurrence of a named waypoint, track, or course. Heading legs prior to the first named waypoint or after the last named waypoint do not have to be loaded from the database.
(6) The means to display the following items, either in the pilot’s primary field of view, or on a readily accessible display page:
(a) The active navigation sensor type;
(b) The identification of the active (To) waypoint;
(c) The distan ce and bearing to the active (To) waypoint; and
(d) The ground speed or time to the active (To) waypoint.
(7) The capability to execute a “Direct to” function.
(8) The capability for automatic leg sequencing with display to the pilots.
(9) The capability to execute RNP 1 terminal procedures extracted from the onboard database including the capability to execute fly-over and fly-by turns.
(10) The system must have the capability to automatically execute leg transitions and maintain tracks consistent with the following ARINC 424 path terminators, or their equivalent:
(a) Initial fix (IF);
(b) Course to fix (CF);
(c) Direct to fix (DF); and
(d) Track to fix (TF).
Note: Path terminators are defined in ARINC Specification 424, and their application is described in more detail in RTCA documents DO-236B and DO-201A.
(11) The aircraft must have the capability to automatically execute leg transitions consistent with heading to altitude (VA), heading to manual (VM) and heading to intercept (VI) ARINC 424 path terminators. An alternate acceptable method is the capability to manually fly the aircraft on a heading to intercept a course or to go direct to another fix after reaching a procedure-specified altitude.
(12) The aircraft must have the capability to automatically execute leg transitions consistent with course to altitude (CA) and from a fix to manual termination (FM) ARINC 424 path terminators. An alternate acceptable method is the RNP system must permit the pilot to readily designate a waypoint and select a desired course to or from a designated waypoint.
(13) The capability to load a RNP 1 procedure from the database, by procedure name, into the area navigation system.
(14) The capability to display an indication of the RNP 1 system failure in the pilot’s primary field of view.
i. Database Integrity.
The navigation database suppliers must com ply with RTCA/DO-200A. A Type 2 LOA, issued by the appropriate regulatory authority, demonstrates compliance with this criteria.
Type 2 LOAs issued prior to this AC are considered compliant.
9-4. System Eligibility and Approval for RNP 1 Operations.
a. Eligib ility for RNP Terminal Area Operations.
The following systems meet the criteria defined in this AC. This equipment still requires evaluation by the manufacturer against all the functional and performance requirements in this AC.
(1) Aircraft with a TSO-C129(AR) Class A1 system (without deviation from the functionality in chapter 14) or a TSO-C146(AR) Class 1, 2, or 3 system (without deviation from the functionality in chapter 14) that are installed for IFR use in accordance with this AC.
(2) Aircraft with TSO-C129(AR) Class B or C sensors, TSO-C196 sensors, or TSO-C145(AR) Class 1, 2, or 3 sensors installed according to this AC in an FMS that meets the requirements of TSO-C115b.
Note: Multi-sensor systems may also have incomplete system TSO-C129(AR) Class A or TSO-C146(AR) Class Gamma approvals (see paragraphs 3-1.d and 3-2.e).
b. System Eligibility for RNP 1 Operations.
(1) Standalone TSO-C129(AR) Class A1 or A2 systems (without deviation from the functionality in chapter 14), or TSO-C146(AR) Class 1, 2, or 3 systems (without deviation from the functionality in chapter 14) meet the aircraft qualification requirements for RNP 1 operations. GPS systems must be installed in accordance with this AC.
(2) Multi-sensor systems using (without deviation from the functionality in chapter 14) TSO-C129(AR) Class B or Class C sensors, TSO-C196 sensors, or TSO-C145(AR) Class 1, 2, or 3 sensors meet the aircraft qualification requirements for RNP 1 operations provided that the installations comply with the criteria in this AC. RNP systems must be installed in accordance with this AC and the associated FMS must comply with TSO-C115b.
Note: Multi-sensor systems may also have incomplete system TSO-C129(AR) Class A or TSO-C146(AR) Class Gamma approvals (see paragraphs 3-1.d and 3-2.e).
(3) Multi-sensor systems that rely on ground-based NAVAIDS. Multi-sensor systems that require the use of ground-based NAVAIDS, such as DME/DME, can be used to conduct RNP 1 operations provided that the AFM/RFM or AFMS/RFMS shows the aircraft is approved for RNP instrument flight operations, the aircraft meets the functional and performance criteria in this chapter (e.g., RNP performance monitoring and alerting), and the criteria of chapter 6 appropriate to the ground-based NAVAIDS and/or inertial systems used.