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.
Chapter 10. Equipmen t Performance - Baro-VNAV.
10-1. General Limitations for Operations under IFR.
a. A baro-VNAV system may be approved for enroute, terminal, and approach use within the contiguous United States, Alaska, and Hawaii. However, unless compensated for temperature, baro-VNAV equipment can only be used within the limitations for temperature published on approach procedure charts.
b. Systems providing temperature compensation to the barometric VNAV guidance must comply with RTCA/DO-236B, appendix H.2. This enables baro-VNAV operations outside of the temperature limits published on approach procedure charts.
(1) Equipment manufacturers may include compensation for temperatures above and below the limits published on approach charts.
Note: Any equipment limitations must be documented in the installation manual.
(2) Temperature compensation may be provided on segments outside of the final approach segment if the equipment includes a method for the flightcrew to inhibit the compensation function.
Note: Aviation authorities in different countries may or may not authorize temperature compensation outside the final approach segment.
(3) Baro-VNAV equipment may also be used to provide advisory vertical guidance to aid in more efficient and precise operation of the aircraft for enroute, terminal, and/or approach operations (see chapter 4). The primary barometric altimeter will be the primary altitude reference for all flight operations.
(4) Baro-VNAV performance has not been shown to be adequate for vertical guidance on LPV or GLS approaches.
10-2. Baro-VNAV Equipment Performance for Operations under IFR.
a. The initial certification of a baro-VNAV system requires an engineering evaluation because of the need to v erify performance, failure indications, environmental qualifications, etc.
Subsequent installations of the same baro-VNAV equipment system in other aircraft may require additional engineering evaluation, depending upon the degree of integration with other aircraft systems; in particular, autopilot and FD systems.
b. For enroute, terminal, and approach IFR operations, the airborne baro-VNAV system must have TSE components in the vertical direction that are less than those shown in table 6 below, 99.7 % of the flying time (reference RTCA/DO-236B, paragraph 2.1.2).
Note: GPS/SBAS Class 2 and 3 as well as GPS/GBAS vertical po sitioning performance exceeds the accuracy requirements of a barometric sensor used for final approach VNAV. The GPS/SBAS 50m Vertical Alert Limit (VAL) used for LNAV/VNAV is consistent with baro-VNAV and may also be used to comply with RNP approach.
Altitude Region (MSL) Level Flight Segments & Climb/Descent Intercept of Clearance Altitudes Flight Along Specified Vertical Profile At or below 5000 ft.
150 ft. 160 ft.
5000 ft. to 10000 ft 200 ft. 210 ft.
10000 ft. to 29,000 ft 200 ft. 210 ft.
Above 29,000 ft to 41,000 ft 200 ft.
(See Note 2) 260 ft.
Table 6. Vertical Path Performance Limit for Baro-VNAV
Note 1: These requirements are based upon airborne altimetry and avionics systems that provide performance consistent with reduced vertical separation minimums (RVSM) requirements.
Note 2: For aircraft type designs prior to January 1, 1997, the value is 200 ft. in the cruise flight envelope and is not to exceed 250 ft. over the full aircraft operating envelope.
Basic height-keeping parameters for 1000 ft. vertical separation minimum between flight levels 290 and 410 are in ICAO Document 9574, Manual on Implementation of 1000 ft. Vertical Separation Minimum between FL 290-FL410 Inclusive.
Note 3: Baro-VNAV equipment error includes all errors resulting from the vertical guidance equipment installation.
This includes errors of the altimeter system and along-track or horizontal coupling error.
Note 4: Table 6 does not address altitudes above FL 410 because current altimetry and baro-VNAV systems are adequate for the 2,000 ft. air traffic control vertical separation criteria.
c. Flightcrew Inputs.
(1) The altitude associated w ith the active waypoint should be to the nearest 100 feet for enroute and terminal flight phases; and, nearest 10 feet for the approach phase. If provided, waypoint horizontal position should be in increments not greater than 0.1 nautical miles.
(2) The ascent or decent angle should be to at least the nearest 0.1 degree, for equipment that specifies gradient angles.
(3) The station elevation, if necessary for equipment employing slant range error correction, should be at least to the nearest 1,000 feet for enroute and terminal flight phases;
and, to the nearest 100 feet for the approach phase.
(4) For terminal and approach operations, the ability to enter the altitude associated with at least eight (for TO-FROM equipment) or nine (for TO-TO equipment) successive waypoints.
(5) A means to confirm input data correctness prior to the system using the new data.
d. System Displays.
(1) The system displays should give no operationally misleading information.
(2) There should be a continuous display of vertical path deviation with the performance indicated in table 7 below.
Enroute/Terminal (feet) Approach (feet) Minimum Full-Scale Deflection ≥ 500 ≥ 150 (see note) Readability ≤ 100 ≤ 30 Minimum Discernable Movement ≤ 10 ≤ 5 Table 7. Vertical Path Deviations
Note: Smaller values of minimum full-scale deflection for approach may be acceptable provided the proposed value is found satisfactory by an engineering evaluation.
(3) The vertical guidance presentation should be compatible with the aircraft’s flight instrumentation such that the pilot is continuously furnished the aircraft’s vertical deviation with respect to the pre-programmed ascent/descent or level flight profile.
e. Alert Indications.
Alert indications for the system should be located on or near the vertical path deviation indicator and should provide a readily discernible annunciation to the pilot(s) for any of the following:
(1) Inadequate or invalid navigation signals or sources;
(2) Absence of primary power;
(3) Inadequate or invalid navigation displays or output sources; and
(4) Equipment failures.
Note: These failure/status indications must occur independently of any operator action. Power or navigation equipment failures may be indicated in a common manner.
In the approach mode, the lack of adequate navigation signals or sources will be annunciated by means of a flag displayed on the primary vertical navigation display. In other modes, an appropriately located annunciator may be used.
f. Additional Constraints.
(1) The baro-VNAV equipment should indicate the aircraft vertical path position to the accuracy specified in paragraph 10-2.b within five seconds after any maneuvering or changes in attitude encountered in normal operations.
(2) The system should be capable of providing navigation guidance to the accuracy specified in paragraph 10-2.b within 20 seconds after input of the desired vertical track information (assuming sensor outputs are available).
(3) Navigation guidance should be available within five seconds of waypoint data input.
(4) The equipment should have the capability to meet the criteria outlined in paragraph 10-2 throughout the range of environmental conditions that will be encountered in actual service. Exposing the equipment to the environmental test conditions of TSO-C115b may be used to demonstrate this capability. The environmental test conditions contained in RTCA/DO-160F may be used to demonstrate this ability for baro-VNAV systems certified independent of a multi-sensor RNAV system.
Note: Previously certified baro-VNAV systems may have used an earlier RTCA/DO-160 revision. This equipment may still be installed within the provisions of its original certification.