Chapter 8 Use Of TSO Authorized Components In IMA Systems.
8-1. IMA Systems and TSOs.
a. IMA systems, depending on the specific aircraft or engine application, may combine many functions that were historically in functionally and physically separated systems. These IMA functions are made up of hardware and software components, each of which may be authorized by TSO, either complete or incomplete. Additionally, hardware modules, cabinets, and racks that host the IMA hardware modules may also be authorized by TSO.
b. TSO authorizations are allowed under 14 CFR part 21, subpart O. Your responsible ACO can explain how we evaluate and issue TSOAs and letters of TSO design approval (LODA) for aviation-related articles.
c. TSOs associated with IMA systems are:
(1) TSO-C153, which covers two types of hardware used in IMA systems: generic hardware modules and cabinets/racks that host hardware modules.
(2) Functional TSOs. See paragraph 8-7 below and refer to Appendix G for examples of functional TSOs. You should keep in mind that this term is not normally used except in the context of IMA systems.
d. RTCA/DO-297 does not specifically address TSO authorized articles within an IMA system. This chapter offers you a way to obtain approval for IMA systems that contain hardware and/or software components authorized by TSO.
e. Due to the high integration, functional TSO data packages for IMA systems are typically developed in parallel with the TC/ST/AT/ASTC effort. In these cases, you should not submit TSO data to the ACO for authorization until the TC/STC/ATC/ASTC testing for the IMA system is completed and the final IMA system configuration is established. This will ensure that the IMA system meets all required TSO MPS. Alternatively, compliance data for TSO authorization and compliance data for the TC/STC/ATC/ASTC maybe be submitted to the appropriate FAA offices concurrently, such that the TSO authorization may be issued concurrently with the aircraft/engine certificate. This alternative approach requires a high level of coordination between the responsible FAA offices to ensure that issues that arise in one area do not affect the
8-2. TSO-C153 Authorization for IMA Hardware Components.
a. To obtain TSO-C153 authorization, the applicant for TSO authorization must demonstrate that the individual hardware components meet the MPS and defined subset of RTCA/DO-160F environmental qualification requirements in TSO-C153, as described in Appendix A. See § 21.616(c). TSO-C153 does not provide either functional or installation approval.
b. The applicant for an IMA Component Acceptance Letter may use TSO-C153 authorization as compliance data to obtain IMA component acceptance for IMA hardware components. See RTCA/DO-297, Table 4.
8-3. Functional TSO Authorization.
a. A functional TSO is a TSO with a defined aircraft functionality. For example, TSO- C106 is for an air data computer. Other examples of functional TSOs are listed in Appendix G of this AC. TSO-C153 is not considered a functional TSO because the hardware element it addresses does not have system level functionality. A functional TSO authorization is issued for a specific IMA system configuration, including hardware and software components, that performs the function defined in the functional TSO MPS. It is not simply for the software component that is loaded into a TSO-C153 authorized hardware element.
b. If the IMA system provides all or part of the functionality required by the functional TSOs MPS and the company applying for functional TSO authorization also controls the design and quality of the complete IMA system, then that company may apply for functional TSO authorizations (either complete or incomplete) for each aircraft function for which there is an applicable functional TSO. As noted above in 8-3(a), the TSO authorization will apply to the IMA system and not a specific IMA component.
Note: Per § 21.601(b)(5), the manufacturer of an article is the "person who controls the processes, and services that are provided by any supplier to that applicant for a TSO authorization. See § 21.601 (b)(5).
c. If the company supplying functional software that will be installed in an IMA system does not control the entire design and quality, per 8-3(b) above, of the article that provides the functionality defined in the functional TSO MPS, then that company may not apply for functional TSO authorization.
d. It should be noted that there will typically be multiple functional TSO authorizations that comprise the IMA system, and the IMA system will likely contain functionality and features not addressed by any TSO. The overall functionality of the IMA system and the portions covered by TSOA versus TC, STC, ATC, or ASTC should be carefully documented and coordinated with the FAA.
8-4. EQT of IMA Components with TSO Authorization.
a. There will be three different stages at which TSO authorized IMA components and the IMA system in which these components are installed need to comply with EQT requirements:
(1) TSO-C153. This TSO contains EQT MPS for IMA hardware modules that qualify for TSO-C153 authorization. Comply with these requirements to obtain TSO-C153 authorization for the generic IMA hardware.
(2) Functional TSO MPS. Each individual functional TSO (see Appendix G for examples) MPS normally include EQT requirements. Comply with these requirements to obtain the individual functional TSO authorization(s).
(3) Aircraft or engine installation EQT requirements. EQT procedures and test configurations are based on the specific aircraft or engine installation of the complete IMA system. Compliance to the aircraft or engine level installation EQT requirements may be completed under the aircraft/engine certification program independent of the TSO authorizations.
Alternatively, certification credit at the aircraft or engine installation level may be taken from the TSO authorizations, if applicable at the installation level.
b. TSO-C153 was written specifically to address how partial EQT compliance at the aircraft or engine installation level can take credit from the EQT compliance from TSO-C153 authorization. EQT procedures that require the test to be run on the specific IMA system configuration as it will be installed on the aircraft or engine should be accomplished during the aircraft or engine TC/ATC/STC/ASTC program. TSO-C153 and Appendix A of this AC address how this can be done.
c. Compliance to the EQT MPS for the individual functional TSO MPS is still required, even with TSO-C153 authorization of the hardware components which host that function.
d. An applicant for an IMA Component Acceptance Letter may use the EQT compliance data from a TSO authorization to use as compliance data for the IMA Component Acceptance Letter process addressed in Chapter 3 of this AC. The IMA Component Acceptance Cover Letter and the accompanying IMA Component Acceptance Letter data sheet should include which EQT are being accepted, including a statement of full or partial compliance and a matrix or table of all EQT procedure testing levels accomplished.
8-5. IMA Component TSO Part Marking.
a. If loadable software components are used with generic hardware modules authorized under TSO-C153 to implement a functional TSO, an applicant for functional TSO authorization should identify the loadable software - both the electronic identification and the physical or electronic media containing the loadable functional software - with the functional TSO identification.
b. The generic hardware components authorized by TSO-C153 must be permanently marked as being authorized under that TSO, in addition to any electronic identification. See § 21.607(d).
c. See paragraph 7-3 for electronic identification guidance.
8-6. Integration of TSO Authorized Components in IMA Systems.
a. The applicant should demonstrate that all RTCA/DO-297 objectives required to obtain Acceptance of the IMA modules, applications, system, and installation into the aircraft or engine have been met. This is true regardless whether any of the modules or applications are also part of a TSO authorized article as described above in paragraph 8-3. The TSO authorization for the IMA function may be used, if relevant, in showing that you met RTCA/DO-297 objectives. The presence of a TSO authorization in no way removes or reduces your responsibilities as an applicant, which is to ensure that the installed IMA system - including any TSO authorized components - meets the appropriate aircraft and engine regulations and the guidance in this AC.
b. Functional TSOs, such as TSO-C113, Airborne Multipurpose Electronic Displays, do not normally cover integration with other aircraft functions or hardware/software components in the integrated IMA system. Each TSO MPS is normally written assuming that it is a stand-alone function and that no integration requirements exist beyond integration into the aircraft. For this reason, additional work is likely to be required beyond the TSO authorizations when showing compliance at the integrated IMA system level. Please refer to RTCA/DO-297, subsection 4.4.
c. The installation instructions for TSO authorized IMA components should include all information necessary for the applicant and/or the IMA developer/system integrator to fully integrated the TSO authorized IMA component into the IMA system.
8-7. Aircraft Installation Approval of IMA Systems Including TSO Authorized Components.
a. The applicant must demonstrate that the installed IMA system configuration - including both hardware and software components - and performance meets the appropriate aircraft and engine certification basis. See § 21.20. This demonstration should include functional performance, interoperability, aircraft-level and system-level safety assessments, environmental qualification, system integration test, flight-test, software and hardware assurance, etc., as required to show compliance to the regulations.
b. The applicant may use TSO authorizations to support airworthiness assessment if you show that the TSO requirements apply to the installation into the aircraft or engine. Any change to the hardware or software configuration of an IMA component must be controlled at both the TSO and the aircraft installation level. See §§ 21.31 and 21.611.
8-8. Roles and Responsibilities When TSO Authorized Components Are Used in IMA Systems.
This section identifies the major roles and responsibilities for the TSO-C153 applicant, the functional TSO applicant, and the aircraft/engine applicant when TSO authorized components are used. These lists are not all-inclusive. We encourage all affected parties to coordinate with us throughout the entire IMA system development. See Appendix A for more guidance applicable to TSO-C153 authorization.
a. TSO-C153 Applicant Roles and Responsibilities:
(1) Apply for TSO-C153. If you are a manufacturer of a TSO article, due to the complexity of IMA projects, we recommend that you coordinate with us early in the program.
(2) Build an MPS for the hardware element according to TSO-C153. Ensure that you document all the appropriate items in TSO-C153, Appendix 1 and that we approved them.
(3) Develop and implement part identification and configuration management functionality into hardware elements. The configuration management and part identification approach should follow chapter 5 and paragraphs 7-3 and 8-5 of this AC.
(4) Coordinate with the applicant and/or IMA developer/system integrator who will be integrating and installing the hardware elements on the aircraft to ensure that the relevant issues are identified and addressed as early as possible.
(5) Design and build hardware elements per TSO-C153 and the MPS.
(6) Perform the tests necessary to demonstrate compliance with the TSO-C153 and the MPS. See paragraph 8-4 and appendix A of this AC. If special purpose test software is used for EQT, validate and control the configuration of the hardware elements and software components to ensure the validity of the testing.
(7) Submit the data package (the information in TSO-C153 paragraph 5, including the MPS) to your responsible ACO for review and issue of TSO authorization.
(8) Apply for changes to TSO-C153 elements as design changes occur. Notity TC, ATC, STC, and ASTC holders and functional TSO holders, if any, of the design change.
b. Functional TSO Applicant Roles and Responsibilities.
(1) Apply for functional TSO to your responsible ACO.
(2) Design the system according to the appropriate TSO MPS.
(3) Identify the usage domain in which the TSO authorized IMA component was shown to meet the TSO MPS. If the environment in which the component verification was conducted is not exactly the same as the usage domain of the completed IMA system, then you should perform analysis and/or testing to demonstrate those differences do not affect the use of the IMA component within the intended usage domain.
(4) Identify and address all integration and approval issues with the IMA hardware component that will host the functional TSO software. Coordinate these issues with the applicant and/or the IMA developer/system integrator (if different than the functional TSO applicant).
(5) Develop mapping between the TSO requirements and the IMA system implementation - for example, a mapping matrix. Mapping should identify TSO requirements that are fully met, partially met, or not met at all. This includes any partial compliance to RTCA/DO-178B for software, RTCA/DO-254 for CEH, and RTCA/DO-160F for EQT.
(6) Identify any limitations regarding the use of the IMA component in an IMA system.
(7) Refer to FAA Order 8150.1, Technical Standard Order Program, as needed to understand the FAA policy regarding TSO authorized articles. You should contact your responsible ACO if you have any questions you cannot answer.
(8) Identify functions in the IMA system not addressed by the TSO. Any functionality not specifically addressed by the functional TSO MPS may require deviations. This additional functionality may be classified as a "non-TSO function", or it may be small enough in nature or closely related to the functional TSO, such that the applicant for a functional TSO classifies it as a "feature." Both non-TSO functions and features should be documented and addressed.
(9) Perform tests to demonstrate compliance to the functional TSO or functional performance standards. Some required EQT may not have been accomplished during TSO-C153 authorization. You should demonstrate that all testing, including EQTs required for the functional TSO, has been accomplished. If special purpose test software is used for environmental qualification, you should verify and control the configuration of the software to ensure the validity of the testing. Credit may be applied for EQT conducted for the TSO-C153 authorization, if appropriate. See paragraph 8-4 for more information.
(10) Submit the data package required by the functional TSO to the responsible ACO for review and issuance of the TSO authorization. Include installation data and configuration of the functional TSO as part of the data package. See paragraph 8-3 for more information.
(11) Apply for changes to functional TSOs, as design changes occur. Notify TC, STC, ATC, and ASTC holders of the design change.
c. Applicant Roles and Responsibilities.
(1) Develop and submit a Project-Specific Certification Plan (PSCP) for the IMA system to the responsible ACO for approval.
(a) We recommend that you include a detailed conformity plan covering all hardware and software components' conformity and installation conformity inspections (including the plan for addressing any "red label" units).
(b) The PSCP should clearly identify what functions will and will not be approved through the TSOA process. This is necessary to identify what will be TSO authorized and what will be TC/STC/ATC/ASTC approved.
(c) The PSCP should address integration and approval of all components of the IMA system (including all hardware elements and software components).
(2) Define aircraft system and performance requirements.
(3) Perform aircraft-level safety assessment per RTCA/DO-297, subsection 5.1 and submit it to your ACO.
(4) Integrate all hardware elements and software components in the IMA system. This task may be accomplished by the IMA developer/system integrator.
(5) Integrate the IMA system into the aircraft or engine.
(6) Ensure that no TSO assumptions are violated in the installation. For example, ensure that relocating the GPS card does not invalidate the environmental qualification credit for the GPS TSO. (See chapter 8 of this AC.)
(7) Develop field-loading procedures to ensure that proper software is loaded on the aircraft. (See paragraphs 5-4 and 7-2 of this AC.)
(8) Verify software and complex electronic hardware issues were properly addressed for the installation. (See RTCA/DO-297, Sections 3, 4, and subsection 5.2.)
(9) Determine appropriate aircraft environmental conditions and ensure that EQTs were performed. (See RTCA/DO-297, subsection 5.2.6.)
(10) Develop all required test plans (see RTCA/DO-297, Section 4) and perform necessary tests.
(11) Develop a plan for addressing human factors issues (see RTCA/DO-297, subsection
3.10) and perform human factors and flight crew evaluations of the IMA system.
(12) Ensure that the IMA system meets all airworthiness requirements.
(13) Submit the functional hazard analyses, safety assessments, hardware design assurance data, software data, test plans, test results, compliance reports, and all other appropriate certification data to the FAA for approval. The preliminary functional hazard analysis and preliminary system safety analysis should be submitted before finalizing the software, CEH, and SEH levels and the IMA architecture.
(14) Maintain aircraft system configuration management. (See RTCA/DO-297.
subsection 3.7 and paragraph 5-1 of this AC.)
(15) Evaluate and document changes to IMA system and elements per § 21.93. (See RTCA/DO-297, subsection 4.6.)
(16) Ensure that aircraft design features address safety. (See RTCA/DO-297, subsection
3.3.)
10/20/10 Appendix A Appendix A Environmental Qualification Guidance for TSO-C153.
1. TSO-C153, Appendix 1 lists environmental qualification tests (EQT) to satisfy the TSO minimum performance standard. Perform these EQTs according to procedures and category levels in RTCA/DO-160F. Select the category levels tested as appropriate for the aircraft installation and environment. The EQTs should apply to functional TSO environmental qualification and may be applied to the aircraft TC, STC, ATC, or ASTC environment qualification.
2. Table 1-1 below lists the RTCA/DO-160F environmental tests that can be accomplished under TSO-C153 authorization, and how they may affect functional TSO authorization.
Table 1-1. RTCA/DO-160F Environmental Qualification Requirements.
RICA/ DO-160F RTCA/DO-160F Required for Required for Section Section Title TSO-C153 Functional TSO # 4 Temperature and Altitude - Not tested Yes Temperature 4 Temperature and Altitude - Yes Yes, TSO-C153 qualification Altitude data may be used by similarity Temperature Variation Not tested Yes 6 Humidity Yes Yes, TSO-C153 qualification data may be used by similarity 7 Operational Shock and Crash Not tested Yes Safety - Operational Shock 7 Operational Shock and Crash Yes Yes, TSO-C153 qualification Safety - Crash Safety data may be used by similarity Vibration Not tested Yes 9 Explosion-proofness Yes, if appropriate Yes, TSO-C153 qualification data may be used by similarity 10 Waterproofness Yes, if appropriate Yes, TSO-C153 qualification data may be used by similarity 11 Fluid Susceptibility Yes, if appropriate Yes, TSO-C153 qualification data may be used by similarity 12 Sand and Dust Yes, if appropriate Yes, TSO-C153 qualification data may be used by similarity 13 Fungus Resistance Yes, if appropriate Yes, TSO-C153 qualification data may be used by similarity A-1
10/20/10 Appendix A RTCA/ DO-160F RTCA/DO-160F Required for Required for Section Section Title TSO-C153 Functional TSO # 14 Salt Spray Yes, if appropriate Yes, TSO-C153 qualification data may be used by similarity 15 Magnetic Effect Yes Yes, TSO-C153 qualification data may be used by similarity 16 Power Input Not tested Yes 17 Voltage Spike Yes Yes, TSO-C153 qualification data may be used by similarity 18 Audio Susceptibility - Power Yes Yes, TSO-C153 qualification Inputs data may be used by similarity 19 Induced Signal Susceptibility Not tested Yes 20 Radio Frequency Susceptibility Not tested Yes 21 Emissions of Radio Frequency Not tested Yes Energy 22 Lightning Induced Transient Not tested Yes Susceptibility 23 Lightning Direct Effects Not tested Yes 24 Icing Yes Yes, TSO-C153 qualification data may be used by similarity 25 Electrostatic Discharge Yes Yes, TSO-C153 qualification data may be used by similarity Note: RTCA/DO-160F, Sections 20 and 22 may require additional testing at aircraft installation.
3. Certain EQTs cannot be appropriately performed on the hardware elements as part of TSO- C153. These EQTs can only be appropriately performed when the IMA system and hardware elements are arranged in the configuration specified for the applicable aircraft, as defined for the aircraft TC, STC, ATC, or ASTC. Also, these EQTs can only be appropriately performed with the functional software installed and operating. Therefore, certain RTCA/DO-160F EQTs are excluded from TSO-C153. You should address these EQTs as part of the functional TSO compliance, or as part of the TC/STC/ATC/ASTC environmental qualification. These tests are described below:
a. EQT for temperature (RTCA/DO-160F, Section 4) and temperature variation (RTCA/DO- 160F, Section 5). Perform these with the cabinet or rack and modules in the hardware configuration intended for the functional TSO authorization or the TC/STC/ATC/ASTC approval. For temperature and temperature variation tests for the functional TSO or A-2
10/20/10 Appendix A TC/ST/AT/ASTC, the hardware module arrangement should represent the expected worstcase temperature conditions. Alternately, applicants for the functional TSO or for aircraft/engine certification may perform engineering analysis, using validated models, of the thermal characteristics of the expected cabinet or rack and module configuration variations to determine temperature test parameters that exceed the worst-case expected temperature conditions. These temperature test parameters could be used instead of the standard RTCA/DO-160F, Sections 4 and 5, temperature conditions.
b. EQT for operational shock (RTCA/DO-160F, Section 7) and vibration (RTCA/DO-160F, Section 8). Perform these with all cabinet/rack module positions occupied in the hardware configuration specified for the functional TSO or TC/STC/ATC/ASTC installation. Alternately, you could perform an engineering analysis, using validated models, of the characteristics of the expected cabinet or rack and module configurations to determine vibration and operational shock test parameters that exceed the worst expected conditions. These test parameters could be used instead of the standard RTCA/DO-160F, Sections 7 and 8 conditions.
c. EQT for induced transients (RTCA/DO-160F, Section 19), radio frequency (RF) susceptibility (RTCA/DO-160F, Section 20), RF emissions (RTCA/DO-160F, Section 21), and lightning induced transients (RTCA/DO-160F, Section 22). These are most appropriately performed with the functional hardware and software in the IMA system. This is because the response of the system may be highly dependent on the functional software and hardware.
Therefore, perform these EQTs as part of the functional TSO compliance or as part of the TC/STC/ATC/ASTC environmental qualification.
d. EQT for lightning and HIRF protection. Perform these with the hardware elements and software components loaded in the configuration specified for the applicable aircraft, per the lightning regulations, ACs, and the HIRF policy. The interface wiring and connected equipment should represent the wiring and connected equipment installed in the aircraft.
4. You may use EQT performed for a single functional TSO authorization or aircraft TC/STC/ATC/ASTC to support other applications for functional TSOs or aircraft TC/STC/ATC/ASTCs with similar configurations. A TSO applicant may use similarity assessment and worst-case test conditions to minimize the EQT required for subsequent functional TSO applications or aircraft TC/STC/ATC/ASTC. Your use of the environmental qualification data should be accompanied by a rational engincering analysis of the differences between hardware and software configuration used during the original environmental tests and the proposed new configuration. The engincering analysis may consider worst-case environmental limits developed above.
5. The functional TSO qualification data sheet should state explicitly the RTCA/DO-160F test categories and tests performed in the functional TSO configuration and the test categories and tests performed in the TSO-C153 configuration. Include this information in the installation instructions.
A-3
10/20/10 Appendix A
6. Hardware modules and software components providing a function that lacks an applicable functional TSO must meet the TC/STC/ATC/ASTC environmental requirements. See § 21.31.
7. You must evaluate all hardware elements before installation to ensure that the TC/STC/ATC/ASTC environmental requirements have been satisfied. See § 21.31.