g. This AC is not m andatory and is not a regulation. This AC describes an acceptable means, but not the only means, to comply with applicable regulations.
h. This AC provides guidance information intended for new approvals. This AC is not intended to modify, change or cancel existing equipment design or airworthiness approvals.
Equipment with existing approvals can continue to be installed within the provisions of their original design and airworthiness certification.
i. The guidance in this AC cannot ensure compliance with Title 14 of the Code of Federal Regulations (CFR) parts 23, 25, 27, and 29 airworthiness regulations for every possible installation configuration. The applicant remains responsible for regulatory compliance and should work closely with their geographic aircraft certification office (ACO) to ensure regulatory compliance. Mandatory terms such as “must” used in this AC are only applicable when following the compliance method outlined.
j. In lieu of following this method without deviation, the applicant may elect to follow an alternate method, provided the alternate method is also found by the Federal Aviation Administration (FAA) to be an acceptable means of complying with the requirements of the federal aviation regulations 14 CFR.
1-2. Audience.
This AC is for aircraft m anufacturers, avionics manufacturers, installation shops, or other applicants seeking design and/or airworthiness approval for the positioning and navigation systems described in this document.
1-3. Cancellation.
a. This AC supersedes the ACs listed b elow. Equipment previously approved per the guidance in the superseded ACs is still valid for the operations and conditions stated in their approvals. The following documents are cancelled:
(1) AC 20-129, Airworthiness Approval of Vertical Navigation (VNAV) Systems for use in the U.S. National Airspace System (NAS) and Alaska.
(2) AC 20-130A, Airworthiness Approval of Navigation or Flight Management Systems Integrating Multiple Navigation Sensors.
(3) AC 20-138B, Airworthiness Approval of Positioning and Navigation Systems.
(4) AC 25-4, Inertial Navigation Systems.
b. This AC supersedes the airworthiness considerations in AC 90-45A, Approval of Area Navigation Systems for use in the U.S. National Airspace System. Equipment previously approved per the airworthiness guidance in AC 90-45A is still valid for the operations and conditions stated in their approvals.
1-4. Frequently Asked Questions.
This paragraph contains a list of questions that have been raised since AC 20-138B was first published. The responses to these questions are intended to help applicants interpret the guidance contained in this AC.
a. Ground Proxim ity Warning System/Terrain Awareness and Warning System (GPWS/TAWS) Mode 5 alert.
(1) Question: Is a GPWS or Class A TAWS Mode 5 alert a hard requirement to add localizer performance with vertical guidance (LPV) or GBAS landing system (GLS) capability?
(2) Answer: No. It is not the FAA’s intent to burden installers by changing the GPWS or TAWS functions; impacting the GPWS or TAWS technical standard order authorization (TSOA); or, requiring that either GPWS or TAWS become the only means to provide the function. The intent is to promote the GPWS/TAWS safety benefits by including a comparable alerting function during LPV or GLS approaches for deviations below glideslope.
Using the GPWS or TAWS Mode 5 alerting to provide the function is certainly acceptable, but is not required as the only acceptable method. See paragraphs 14-6.8 and 14-8.13 for clarification and additional guidance.
b. Using the term vertical navigation (VNAV).
(1) Question: Doesn’t RTCA/DO-229D assign a very specific meaning to the term ‘VNAV’ and dictate the term’s specific uses for SBAS-based vertical navigation?
(2) Answer: No. RTCA/DO-229D, section 2.2.1.1.7 provides a recommended usage for the ‘VNAV’ label, but only requires that the label be used in a consistent manner.
‘VNAV’ can be used for a lateral navigation/vertical navigation (LNAV/VNAV) approach procedure generated by GPS/SBAS-based or barometric-based vertical navigation capability (GPS/GBAS does not provide an LNAV/VNAV approach capability). The ‘VNAV’ label can also be used for an advisory vertical navigation function that provides vertical path deviation guidance indications on a non-essential, not-required basis. Refer to the following AC 20-138C chapters for additional information:
Chapter 4, Advisory Vertical Guidance;
Chapter 10, Baro-VNAV;
Chapter 11, section 11-8, General Human Factors Considerations;
Chapter 14, section 14-6.6, GPS/SBAS Equipment Annunciations; and, Chapter 17, section 17-5, Baro-VNAV integration with GNSS-Provided Vertical Guidance.
c. Tightly-coupled inertial navigation system/global positioning system (INS/GPS).
(1) Question: AC 20-138B, section 6-7 c. includes the following statement: "The FAA assumes that there is a limitation on the use of the GPS/inertial position data output to support enroute through lateral navigation (LNAV) approach only." Can you please explain the basis of this assumption? It appears to exclude the use of tightly coupled INS/GPS for oceanic use. Is this the intent? Or, is the intent to exclude it for use for LPV?
(2) Answer: Paragraph 6-6 addresses loosely-coupled systems and paragraph 6-7 addresses tightly-coupled systems. There is no intent to exclude either loosely-coupled or tightly-coupled INS/GPS from oceanic use. However, un-augmented GPS, even with tightlycoupled INS, is not adequate for vertical approach capability, and hybrid inertial vertical approach capability is not addressed in RTCA/DO-229D, appendix R. As stated in this AC, a GPS-based vertical approach capability requires GPS/SBAS or GPS/GBAS augmentation.
d. Flight management system (FMS) limitations.
(1) Question: AC 20-130A, section 5.d.(2) contained a limitation on FMS use and required an alternate means of navigation for the route flown. AC 20-138B does not include this section or make a mention of this limitation. What was the reasoning behind not including a similar section in AC 20-138B? Is there some higher level guidance that addresses this or is it left up to the safety analysis to address the need for an alternate means of navigation?
(2) Answer: It is important to differentiate between operational limitations and equipment performance limitations. AC 20-138C addresses equipment performance limitations while the 90-series ACs produced by Flight Standards address operational limitations (for example, 90-100, 90-101A, 90-105 for RNAV, RNP AR, and RNP respectively) as well as the Airman's Information Manual and operational rules (parts 91, 121, 135).
(a) AC 20-130A was written prior to implementing performance-based navigation concepts and the evolving RNAV/RNP-based National Airspace System. An FMS incorporating multiple navigation sensor inputs by its very nature has multiple sources of navigation, but the individual sensors have performance limitations on their navigation capabilities. Accordingly, the FMS functions will meet different requirements depending upon the sensors involved and the intended navigation capability. AC 20-138C addresses the performance limitations of the individual sensors contained in the document. These performance limitations must be considered for the overall intended function at the aircraft level during the airworthiness approval (i.e., during the type certificate (TC), amended type certificate (ATC), or supplemental type certificate (STC) approval) to determine any limitations on the aircraft.
(b) In summary, operational rules dictate the navigation equipage requirements.
It is up to the operator to determine how to comply based on their specific operating rules and mission needs.
Chapter 2. T echnical Standard Order Authorization (TSOA) and Airworthiness Approval Considerations - General.
2-1. Guidance for TSOA/Letter of Design Approval (LODA) and Air worthiness Approvals.
Title 14 CFR part 21; subparts D, E, and O provide the regulatory basis defining changes to TC (major/minor changes to aircraft type design), STC, and TSOAs. The regulations and technical standard orders (TSO) can be found at: http://rgl.faa.gov. This chapter provides general guidance on TSOA/LODA and airworthiness approval considerations specific to positioning and navigation equipment.
2-2. TSOA.
a. Several TS Os are available for positioning and navigation-related equipment and components (see appendix 8 of this AC). New TSOs will be written to address modernized GPS and other GNSSs once appropriate equipment standards are in place. It is beneficial to involve the ACO (both engineers and flight test pilots) in equipment evaluations as early as possible for four primary reasons:
(1) Obtaining a TSOA/LODA does not ensure that the equipment will satisfy all of the applicable operational requirements and/or airworthiness regulations when it is installed.
(2) Positioning and navigation equipment has become increasingly more complex and workload intensive with no standardized pilot interface. The human factors evaluation of the equipment is often subjective.
(3) There is no one, single standard for interfacing positioning and navigation equipment to other equipment on-board the aircraft such as displays, autopilots, and terrain warning systems. Positioning and navigation equipment manufacturers should develop compatibility data relative to other equipment for inclusion within the installation manual.
(4) The installed intended function for the equipment needs to be compatible with the original design for the system, including software and hardware design assurance levels.
For example, a decision by the positioning and navigation equipment manufacturer to develop system software to RTCA, Inc. document (RTCA)/(DO)-178B, Software Considerations in Airborne Systems and Equipment Certification, dated December 1, 1992, Level C, may limit installation eligibility if that equipment contributes to failure conditions of other systems that perform critical functions to a higher software design assurance level.
b. It is recommended that the positioning and navigation equipment manufacturer elect to obtain an STC for equipment installation concurrent with obtaining the TSOA/LODA. This has proven to be an effective method to aid installations.
Note: Any applicant may apply for an equipment installation STC. It is not this paragraph’s intent to limit positioning and navigation installation STCs solely to avionics manufacturers.
c. The installation manual and other data approved during the TSOA process can be used as a source of approved data to support an installation airworthiness compliance finding provided the data is applicable to the installation airworthiness requirements (see AC 21-50 (latest revision), Installation of TSOA Articles and LODA Appliances).
2-3. STC-Approved Model List (AML).
a. All STC applican ts are encouraged to use an AML for aircraft makes/models (including 14 CFR parts 23, 25, 27, and 29 aircraft) with similar characteristics and compatible equipment configurations to streamline the approval of subsequent installations. Applicants and ACOs need to contact the applicable directorate for specific policy and guidance information on obtaining an STC-AML.
b. Using the STC-AML method can simplify follow-on installations for makes/models on the AML. The installer needs access to the STC approved data; apply the approved data;
and comply with the detailed installation instructions. The installer then needs only complete FAA Form 337, Major Repair and Alteration (Airframe, Powerplant, Propeller, Appliance), identifying the nature of the change to return the aircraft to service (see AC 43.9-1 (latest revision), Instructions for Completion of FAA Form 337).
c. GPS and GPS/SBAS equipment airworthiness approval is not considered novel or unusual per 14 CFR 21.16 and applicants can use designees during the STC process.
2-4. Type Certificate.
Position ing and navigation equipment manufacturers are also encouraged to work with TC holders. This has also proven to be an effective method to aid installations.
Chapter 3. TSO Authorization.
3-1. TSO-C196(AR).
a. TSO-C196a, Airborne Supplemental Navigation Sensors for Global Positioning System Equipment Using Aircraft-Based Augmentation, defines an acceptable standard for GPS equipm ent without ground-based or space-based augmentations. The TSO has been updated to revision ‘a’ for harmonization with TSO-C129a’s cancellation and is intended as the aircraftbased augmentation GPS sensor standard for TSOA/LODA applicants. TSO-C196(AR) equipment has a performance limitation that requires other positioning and navigation systems appropriate to the operation on-board the aircraft.
Note: TSO-C129a has been cancelled, but this does not affect equipment with an existing TSOA/LODA (see paragraph 3-1.c).
b. TSO-C196(AR) defines GPS sensor equipment that incorporates many processing improvements found in the GPS/SBAS equipment minimum operational performance standards (MOPS); but, without the GPS/SBAS requirements. Two improvement examples are: a requirement for the receiver to properly account for satellite range error if it is reflected in the User Range Accuracy index (commonly referred to as being “Selective Availability aware”), and requirements to ensure performance is not degraded due to an increasing radio frequency noise environment as other satellite systems become available.
(1) TSOA/LODA applicants may wish to have a previously approved TSO-C145b/c, Airborne Navigation Sensors Using the Global Positioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS), sensor approved as a TSO-C196a sensor. It is acceptable for these TSO-C196a applicants to take certification credit by re-using data developed during a previous TSO-C145b/c TSOA/LODA approval. RTCA/DO-316, Minimum Operational Performance Standards for Global Positioning System/Aircraft-Based Augmentation System Airborne Equipment, dated April 14, 2009, implemented by TSO- C196(AR) was developed from RTCA/DO-229D, Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System (GPS/WAAS) Airborne Equipment, dated December 3, 2006, implemented by TSO-C145b/c. RTCA/DO- 229D meets or exceeds the performance requirements for TSO-C196(AR). The original RTCA/DO-178B documentation can be re-used if there are no software changes.
(2) Applicants seeking a TSO-C196a TSOA/LODA based on a previously approved TSO-C145b/c sensor must maintain separate part numbers for each unit. It is not acceptable to have both a TSO-C145(AR) and TSO-C196(AR) TSOA/LODA simultaneously on the same article (see paragraph 3-5.b(4)).
Note: Maintaining separate part numbers might only require different software part numbers.
(3) It is acceptable for TSOA/LODA applicants with TSO-C145b/c sensors to simply disable the GPS/SBAS tracking loops in their equipment to qualify as a TSO-C196a 7
sensor.
(4) TSOA/LODA applican ts with TSO-C145a sensors will need to show requirements traceability between RTCA/DO-229C and RTCA/DO-316 along with data applicability to receive appropriate certification credit. In particular, applicants will need to show compliance to all RTCA/DO-316 requirements not addressed in RTCA/DO-229C, and requirements that are more stringent such as enroute/terminal mode accuracy and the broadband external interference noise environment.
c. TSO-C129a was cancelled effective October 21, 2011, but there is no plan to withdraw TSO-C129(AR) authorizations. TSO-C129a cancellation will not affect existing authorizations. Manufacturers can continue production according to their existing TSO-C129(AR) TSOA/LODA. Additionally, the equipment is still eligible for installation according to existing airworthiness approvals and is eligible to receive new airworthiness approvals.
(1) No new TSO-C129a TSOAs/LODAs will be granted after October 21, 2011.
However, we will accept applications for a new TSO-C129a TSOA/LODA until October 21, 2012 if we know that you were working toward a TSO-C129a approval prior to October 21, 2011.
(2) Major changes to the TSO-C129a equipment design will require a new application according to 14 CFR 21.619(b) for TSO-C145c, TSO-C146c or TSO-C196a (or later revisions) except as noted in paragraph 3-1.c(1).
Note: TSO-C129/C129a does not provide sufficient performance for all operational applications.
3-2. TSO-C145(AR)/C146(AR).
a. TSO-C145c, Airborne Navigation Sensors Using the Global P ositioning System (GPS) Augmented by the Wide Area Augmentation System (WAAS) and TSO-C146c, Stand- Alone Airborne Navigation Equipment Using the Global Positioning System (GPS) Augmented by the Satellite Based Augmentation System (SBAS) define an acceptable standard for GPS/SBAS equipment. There is no equipment performance limitation for GPS/SBAS- equipped aircraft to have other positioning and navigation systems on-board.
Note: Refer to the appropriate operating rules and operational guidance documents for equipage requirements.
b. RTCA/DO-229D referenced by the GPS/SBAS TSOs will remain as the MOPS for single-frequency GPS/SBAS equipment. Future multi-frequency/multi-constellation equipment will have a separate MOPS and TSO.
c. There is no plan to withdraw authorizations to the earlier TSO revisions, so manufacturers of TSO-C145a/C146a or TSO-C145b/C146b equipment can continue production according to their TSOA/LODA; and the equipment is still eligible for installation in 8
accordan ce with the guidance in this AC.
d. The difference between revisions ‘b’ and ‘c’ to the GPS/SBAS TSOs is eliminating a 3 decibel (dB) broadband intra-system noise credit for operational Class 1 and Class 2 equipment in RTCA/DO-229D. TSO-C145b/C146b operational Class 3 and Class 4 equipment fully complies with the requirements in TSO-C145c/C146c and is automatically eligible for a revision ‘c’ authorization, i.e., no further evaluation is necessary.
e. TSO-C145b/C146b operational Class 1 and Class 2 equipment that did not claim the 3dB noise credit is also eligible for a revision ‘c’ authorization. The TSOA/LODA holder only needs to provide substantiation that they did not take the noise credit during the original certification.
f. Displays or navigation computers (such as FMSs) may receive a TSO-C146c Class 1, 2, or 3 (functional Class Gamma) incomplete system TSOA/LODA provided they meet the applicable Class Gamma requirements in RTCA/DO-229D and are linked by part number to compatible TSO-C145c sensors in the TSO application documentation. This is an effective method to aid GPS/SBAS installation approvals to make a complete system (sensor, navigation computer, display) at the aircraft level.
Note: See paragraph 3-4 for additional information on FMS incomplete system TSO-C146c Class Gamma TSOA/LODAs and Class Delta-4 FMS implementations.
3-3. TSO-C161a/C162a.
a. TSO-C161a, Ground Based Augmentation Sys tem Positioning and Navigation Equipment, defines an acceptable standard for GPS/GBAS equipment that provides precision approach capability and position/velocity/time (PVT) information to navigation management equipment. TSO-C162a, Ground Based Augmentation System Very High Frequency Data Broadcast Equipment, defines an acceptable standard for GPS/GBAS equipment designed to receive a very high frequency data broadcast (VDB) and output the VDB messages to GPS/GBAS positioning and navigation equipment.
b. TSO-C161a and TSO-C162a invoke only the requirements in RTCA/DO-253C, Minimum Operational Performance Standards for GPS Local Area Augmentation System Airborne Equipment, dated December 16, 2008, that are needed to support Category I (CAT I) precision approach and, if applicable, the GPS/GBAS positioning service. The equipment may output PVT based on either the GPS/GBAS positioning service, or PVT from GPS or GPS/SBAS. The PVT based on GPS/GBAS is only available when the ground station supports the positioning service. TSO-C161a equipment must also obtain a TSO-C145c, TSO-C146c, or TSO-C196a TSOA. Requirements in RTCA/DO-253C needed to support precision approaches beyond CAT I are not invoked in these TSOs as these requirements have not been validated.
Once validated, the FAA will either publish TSO revisions or new TSOs.
c. TSO-C161a and TSO-C162a compliant equipment does not address any RNAV capability. A partial missed approach capability is an option in the GPS/GBAS equipment but is not required (see note). RNAV capability for the initial, intermediate, and missed approach 9
segm ents must be addressed during the aircraft GPS/GBAS integration (see paragraph 14-8.1).
Note: Equipment meeting the RTCA/DO-253C precision and navigation (PAN) requirements can include an optional capability to provide guidance for the initial, straight-out portion of the missed approach segment. However, this capability doesn’t provide guidance for the complete missed approach segment.
3-4. TSO-C115(AR).
a. TSO-C115c, Management System (FMS) Using Multi-Sensor Inputs defines an acceptable certification standard for obtaining design and production approval for multi-sensor navigation systems or FMSs integrating data from multiple navigation sensors. There is no plan to withdraw TSO authorizations granted under TSO-C115b or earlier revisions.
Manufacturers of TSO-C115b, or earlier revision, equipment can continue production according to their TSOA/LODA; and the equipment is still eligible for installation in accordance with the guidance in this AC. However, integrating GNSS into TSO-C115/C115a multi-sensor navigation equipment is considered a major change and requires an application for a TSO-C115c TSOA/LODA.
(1) TSO-C115b only addressed TSO-C129 Class B and C sensors because it was published prior to TSO-C129a, TSO-C145(AR), TSO-C161(AR), and TSO-C196(AR). It is acceptable to integrate any GNSS sensor with TSO-C115b equipment.
Note: The multi-sensor navigation system or FMS must comply with TSO-C115 revision ‘b’ (or a later revision) when integrating GNSS sensors if TSO-C115 is the approval basis. It is not acceptable to use systems certified to earlier TSO-C115 revisions for GNSS sensor integration (see paragraph 3-5.b(1)).
(2) Localizer performance without vertical guidance (LP)/localizer performance with vertical guidance (LPV) is considered a severe major/hazardous failure condition for misleading information (see paragraph 11-2.a). Equipment manufacturers may design FMSs for either a TSO-C146c Class Gamma-3, or Class Delta-4 architecture when integrating LP/LPV capability.
(a) A TSO-C115b (or later revision) FMS designed as a Class Gamma-3 architecture typically has level B software for the LP/LPV processing functions. It is acceptable to have the GPS/SBAS capability and level B software partitioned from other functions in the FMS. See paragraph 3-4.b for additional information on incomplete system TSO-C146c Class Gamma TSOA/LODAs.
(b) TSO-C146c Class Delta-4 provides an ILS look-alike for LP/LPV final approach segment-only capability. A TSO-C115b (or later revision) FMS designed for a Class Delta-4 architecture does not process LP/LPV inputs; does not output LP/LPV deviations, path construction, alerts, etc.; and, does not require the FMS to have a TSO-C146c TSOA/LODA.
The aircraft integration must include a GPS/SBAS sensor that has a TS O-C146c Class Delta-4 TSOA/LODA. See paragraph 3-4.c for additional information on Class Delta-4 implementations.
b. FMS manufacturers may add an incomplete system TSO-C146c TSOA/LODA to FMSs certified to TSO-C115b (or later revision). An appropriate operational class incomplete system TSO-C146c Class Gamma TSOA/LODA provides an established means for the installed FMS to demonstrate navigation computer compliance as a GPS/SBAS system.
Note 1: FMSs that do not meet the applicable RTCA/DO-229D Class Gamma performance requirements can still receive PVT inputs from a TSO- C145(AR) sensor and apply them consistent with their existing approvals. Using a TSO-C145(AR) sensor can remove certain performance limitations associated with a TSO-C129(AR) sensor (see paragraphs 5-5.2.b and 5-
5.2.c).
Note 2: There is significant overlap in requirements between TSO-C146c Class Gamma implementation of RTCA/DO-229D and TSO-C115c implementation of RTCA/DO-283A requirements. Where requirements overlap exists it is acceptable to re-use compliance information from RTCA/DO-229D as the method of demonstrating RTCA/DO-283A compliance. However, applicants remain responsible to ensure all RTCA/DO- 283A requirements are satisfied.
(1) TSO-C146c will take precedence when adding an incomplete system TSO-C146c Class Gamma TSOA/LODA to an FMS with an existing TSO-C115b TSOA/LODA if there are any conflicts between the two TSOs.
(2) TSO-C115c requires RTCA/DO-283A for 2-dimensional RNP navigation computer functions; that is, no VNAV approach capability. The baro-VNAV guidance in this AC must be used when including baro-VNAV for approach capability.
(3) FMSs may qualify as TSO-C146c Class Gamma navigation computer systems when receiving inputs from a TSO-C145c Class Beta-2 or Class Beta-3 sensor. An incomplete system TSO-C146c Class Gamma approval (Gamma-2 or Gamma-3 as appropriate) can be added to the TSO-C115b (or later revision) approval, or replace the TSO-C129(AR) approval if one exists, to provide GPS/SBAS-based VNAV approach capability. Class Gamma-1 can be used for FMSs that don’t intend to process GPS/SBAS vertical deviations.
Note: Several issues must be considered for FMSs integrating both baro-VNAV and GPS/SBAS to provide LNAV/VNAV capability. For example; unambiguous navigation source and approach service level annunciation, discontinuities or jumps when switching 11
fro m baro-VNAV to GPS/SBAS vertical guidance, and prioritizing when to use which source (see paragraphs
6-3.c, 15-2.a), and 17-5).
c. FMSs in typical federated avionics architectures do not need an incomplete system TSO-C146c Class Delta-4 TSOA/LODA since the FMS does not provide or process flight path deviation data or GPS/SBAS alerting functions during the final approach segment. The FMS must be integrated at the aircraft level with a GPS/SBAS sensor that has a TSO-C146c Class Delta-4 TSOA/LODA. The complete system (sensor with Class Delta-4 TSOA/LODA, level B path, and display) will be confirmed at the time of installation. See paragraph 14-2.a regarding displays and path for legacy aircraft retrofit installations previously certified with ILS.
(1) It is acceptable for the Class Delta-4 sensor to reside within the FMS itself provided the LP/LPV outputs are not processed or altered by the FMS (similar to an ILS).
(2) The FMS may provide an interface for pilot control of the Class Delta-4 equipment (such as selecting the approach) and may host the Final Approach Segment (FAS) database for input to the Class Delta-4 equipment. The Class Delta-4 TSOA/LODA holder must list the specific compatible FMS(s) or provide a detailed interface description to establish FMS compatibility in the installation manual.
(3) At the aircraft level, Class Delta-4 implementations depend upon the entire path for the guidance deviations complying with a severe major/hazardous failure condition in modern aircraft with digital data busses. See paragraph 14-2.a regarding displays and path for legacy aircraft retrofit installations previously certified with ILS.
(4) Non-federated FMS architectures, such as integrated modular avionics, may have the Class Delta-4 LP/LPV final approach segment capability residing within the FMS functions or components. The applicable modules for these FMSs will need a TSO-C146c Class Delta-4 TSOA/LODA and appropriate software level for the Class Delta-4 performance requirements listed in RTCA/DO-229D that they provide.
Note: It is also acceptable for applicants with nonfederated FMS architectures to consider pursuing incomplete system TSO-C146c Class Gamma approval for the navigation computer functions/components.
(5) An FMS that is part of an aircraft-level TSO-C146c Class Delta-4 integration normally provides the RNAV capability for the initial and intermediate approach segments to place the aircraft in proper position for the Class Delta-4 GPS/SBAS equipment to conduct the LP/LPV final approach segment. The FMS also provides the RNAV capability for the missed approach segment.
Note: RNAV capability for the initial, intermediate, and missed approach segments can be accomplished by the FMS according to its TSO-C115b (or later revision) or other GNSS TSO approval. However, the FMS will be limited to its approved functions per those TSOs or as 12
13 modified if receiving PVT inputs from a TSO-C145(AR) sensor (see paragraphs 5-5.2.b and 5-5.2.c).
d. Multi-sensor systems must also comply with the appropriate TSO requirements for the individual sensors that are integrated. For example, if distance measuring equipment (DME) is integrated, then the system must also comply with TSO-C66c, Distance Measuring Equipment(DME) Operating Within the Radio Frequency Range of 960 to 1215 Megahertz, for DME equipment. Refer to AC 90-100 (latest revision), U.S. Terminal and Enroute Area Navigation (RNAV) Operations, for operational approval of terminal and enroute area navigation systems for use in the United States national airspace system.
3-5. Multiple TSO Authorizations.
a. Multip le TSO authorizations may be granted for equipment that accomplishes multiple functions. However, the number of TSO markings on positioning and navigation equipment should be minimized to avoid confusion during installation and approval.
b. The following combinations of TSO authorizations must not be granted, as the TSOs either contradict each other or are superfluous to a TSO with broader scope:
(1) TSO-C115/C115a with TSO-C129(AR), TSO-C145(AR)/C146(AR), TSO-C196(AR), or TSO-C161a/C162a).
(2) TSO-C129(AR) Class A with TSO-C146(AR) Class Gamma.
(3) TSO-C129(AR) Class B or Class C with TSO-C145(AR), TSO-C146(AR) or TSO-C196(AR).
(4) TSO-C196(AR) with TSO-C145(AR) or TSO-C146(AR).
Note: The intent is that combinations not specifically prohibited by paragraphs 3-5.b(1) through 3-5.b(4) are acceptable.