ETSO-C153a

• ED Decision 2020/011/R found in: CS-ETSO Amdt 17 - European Technical Standard Orders (Oct 2026)

#### ETSO-C153a *ED Decision 2020/011/R* ##### Integrated Modular Avionics (IMA) Platform and Modules Note: This ETSO standard is identical to the ETSO-2C153 standard. This new revision has the purpose of aligning the ETSO Index with the published FAA TSO-C153a to reflect harmonisation. As a consequence, this standard is moved from Index 2 to Index 1 of CS-ETSO Subpart B. **1 Applicability** This ETSO provides the requirements that IMA modules, designed to be parts of an Integrated Modular Avionics (IMA) platform and manufactured on or after the date of entry into force of this ETSO, must meet in order to be identified with the applicable ETSO marking. See [Appendix 1](#_DxCrossRefBm920220887) for an introduction to IMA and the applicable definitions. EUROCAE ED-124 and RTCA DO-297 recognise an incremental IMA system approval by introducing intermediate acceptance steps. ETSO-C153a authorisation is an optional intermediate step to authorise an IMA platform or IMA modules (independently of the aircraft type approval). It encompasses environmental qualification, hardware development assurance, software development assurance and design approval of the intended function of resource sharing. This ETSO refers to IMA platforms and modules which are appliances composed of hardware, core software or any embedded software module contributing to the intended function of resources sharing. Nevertheless, if the intended function of resource sharing is implemented: — the ‘hardware only’ module is acceptable if no further software module is needed to perform resources sharing; — a single Line Replaceable Unit (LRU) platform (as per EUROCAE ED-124/RTCA DO-297), where the platform is limited to one LRU, is acceptable. Hereinafter, only the term ‘IMA module’ will be used. The following are out of the scope of this ETSO-C153a: — IMA platforms consisting of multiple LRUs or Line Replaceable Modules (LRMs) distributed inside the aircraft that have to be addressed at installation level; — stand-alone core software; — configuration data which are part of the IMA system integration and installation; — hosted applications; and — equipment used to generate radio frequency signals for intentional transmitters. To be eligible for an ETSO-C153a authorisation, an IMA module shall comply with common applicable requirements and shall implement at least one of the function classes below: — CLASS RH: Rack Housing — CLASS PR: Processing — CLASS GP: Graphical Processing — CLASS DS: Data Storage — CLASS IF: Interface — CLASS PS: Power Supply — CLASS DH: Display Head See [Appendix 2](#_DxCrossRefBm920220886) for the common requirements and definitions of function classes. An IMA module can also be compliant with a combination of MPS classes. In this case, the IMA module will be marked with all the classes it covers. However, if a manufacturer voluntarily applies for an ETSO-C153a authorisation, all the classes for which the intended function is implemented shall be compliant. Example: A single LRU platform will be authorised as an ‘ETSO-C153a CLASS PR + DS + IF’ if the intended function of resource sharing is implemented in processing, data storage and the interfaces. For an ETSO-C153a CLASS DH authorisation, the IMA module shall be compliant with the requirements of ETSO-C113(\*) ‘Airborne Multipurpose Electronic Displays’. The IMA module shall be marked with both ETSO-C153a CLASS DH and ETSO-C113. (\*) Please refer to the most recent applicable revision of ETSO-C113. **2 Procedures** 2.1. General The applicable procedures are detailed in Subpart A of CS-ETSO. The data to be submitted to the European Union Aviation Safety Agency (EASA) (hereinafter referred to as ‘the Agency’) is defined in Subpart O of Annex I (Part 21) to Regulation (EU) No 748/2012 and in [Subpart A](#_DxCrossRefBm920220672) of CS-ETSO. 2.2 Specific Additional data which shall be submitted to the Agency by IMA modules manufacturers are specified in [Appendix 3](#_DxCrossRefBm920220885), including the data required by ED-124 Task 1 (See paragraph 3.2.2.1 below). **3 Technical Conditions** 3.1 Basic 3.1.1 Minimum Performance Standard See Appendix 2. 3.1.2 Environmental Standard See CS-ETSO, Subpart A, paragraph 2.1 and [Appendix 4](#_DxCrossRefBm920220884). 3.1.3 Computer Software See CS-ETSO, Subpart A, paragraph 2.2. 3.1.4 Airborne Electronic Hardware See CS-ETSO, Subpart A, paragraph 2.3. 3.2 Specific 3.2.1 Failure Condition Classification It is recognised that IMA modules may be developed independently of specific installation projects and of future hosted aircraft functions, thus preventing the possibility to define the level of the aircraft failure condition, which is out of the scope of this ETSO. However, the module architecture and development will be driven by generic failure conditions. These can be considered as assumptions, which will contribute to determine the Development Assurance Level (DAL) allocation as per CS-ETSO Subpart A, paragraph 2.4. The assumed failure conditions and the resulting DAL are characterisation items and shall be documented in the installation manual and declaration of design and performance (DDP). Qualitative and safety mechanisms requirements for each class are specified in the Minimum Performance Standard in Appendix 2. 3.2.2 Specific Development and Installation Requirements 3.2.2.1 Development process EUROCAE ED-124/RTCA document DO-297 ‘Integrated Modular Avionics (IMA) Development Guidance and Certification Considerations’ contains guidance for IMA developers, application developers, integrators, certification applicants, and those involved in the approval and continuing airworthiness of IMA systems in civil certification projects. In the frame of ETSO-C153a, the development of IMA modules or platforms shall meet the objectives of the EUROCAE ED-124/RTCA document DO-297 guidance related to Task 1 (Table A-1 ‘Objectives’) except as constrained below: Table A-1, Objective 8 is: — applicable to a single LRU platform; and — partially applicable to an IMA module for intrinsic validation and verification activities. (i.e. excluding 4.2.1 h). Note: For Table A-1, Objective 8, the column ‘doc ref’ refers to 5.3 and 5.4, which provide details of objectives with applicability per Task 1 of ED-124 (See Tables 5 and 6). 3.2.2.2 Installation Considerations An ETSO-2153 IMA module is, by definition, an incomplete system. A definition of the activities to be performed to properly use the ETSO-C153a IMA module shall be defined for the installer. The associated test procedures to check that the authorised IMA module is properly installed shall also be documented in the installation manual in order to allow the integrator to perform integration of applications hosted on IMA platforms/modules and their installation on aircraft as per the applicable guidance. **4 Marking** 4.1 General Marking is detailed in Paragraph 1.2 of CS-ETSO, Subpart A. 4.2 Specific The part shall be permanently and legibly marked with the intended function class(es) as defined in Paragraph 1 of this ETSO. This information shall be on the ETSO nameplate or in close proximity to the nameplate. Note: An ETSO-C153a marking does not cover IMA-hosted applications and IMA configuration management, which are software aspects not covered by this ETSO. **5 Availability of Referenced Documents** Please see paragraph 3 of CS-ETSO, Subpart A. [Amdt ETSO/10] [Amdt ETSO/16]