AMC1 21.A.239(d) Design management system

• ED Decision 2022/021/R found in: Initial Airworthiness and Environmental Protection (748/2012) Part-21 Part-21L (Jul 2024)
• ED Decision 2025/016/R found in: Initial Airworthiness and Environmental Protection (748/2012) (Nov 2025)

AMC1 21.A.239(d) Design management system ED Decision 2022/021/R DESIGN ASSURANCE ELEMENT (a)     Reserved (b)     Reserved (c)      Design assurance system The complete design process, starting with the type certification basis, operational sutiability data (OSD) certification basis, as well as environmental protection requirements and product specifications, and culminating with the issuing of a type certificate (TC), is shown in Figure 1, which identifies the relationships between the design, the certification, and the design assurance processes. Effective design assurance requires a continuing evaluation of all the factors that affect the adequacy of the design for the intended applications. In particular, it should be ensured that the product or part complies with the applicable type certification basis, OSD certification basis, and environmental protection requirements, and that it will continue to comply after any change to the TC or any repair. Planned and systematic tasks should therefore be defined and performed from the very beginning of the design activities up to the continued-airworthiness activities. ![Aviation.Bot AI suggestion, not from EASA source: [Image caption skipped for debugging]](/static/files/file_ocz75zUMmy4/image021.png) Figure 1 — RELATIONSHIPS’ CONCEPT IN DESIGN AND CERTIFICATION (1)     Planned and systematic tasks For design organisations that carry out the certification process of products, their planned and systematic tasks should cover the following, and the related procedures should be defined accordingly. (i)      General (A)     Issue or, where applicable, supplement, or amend the handbook in accordance with point [21.A.243](#_DxCrossRefBm1649097316), in particular to indicate the initiation of design activities on a product. (B)     Assure that all the instructions of the handbook are adhered to. (C)     Conduct the certification process. (D)     Nominate staff as ‘compliance verification engineers’ that are responsible for approving compliance documents as defined in point (c)(1)(iii). (E)     Nominate staff that belong to the Office of Airworthiness and are responsible as defined in point (c)(1)(iv). (F)     In the case of an applicant for an STC, obtain the agreement of the TC holder for the proposed supplemental type certificate (STC) to the extent that is defined in point [21.A.115](#_DxCrossRefBm1649096857). (G)     Ensure that there is full and complete liaison between the design organisation and the related organisations that have responsibility for the products and parts that are manufactured according to the type design. (H)     Provide assurance to EASA that any prototype models and test specimens adequately conform to the type design (see point [21.A.33](#_DxCrossRefBm1649096983)(c). (ii)     Head of the design organisation (or deputy) The head of the design organisation (HDO), or an authorised representative, should sign a declaration of compliance (see points [21.A.20](#_DxCrossRefBm1649096852)(d) and [21.A.97](#_DxCrossRefBm1649096997)(b)(3)) with the applicable type certification basis, OSD certification basis, and environmental protection requirements after verifying the satisfactory completion of the certification process. In accordance with point [21.A.20](#_DxCrossRefBm1649096852)(e), the signature of the HDO on the declaration of compliance confirms that the procedures as specified in the handbook have been followed (see also [GM 21.A.265(b)](#_DxCrossRefBm1649097336)). (iii)     Compliance verification (A)     Approval through the signing of all the compliance documents, including test programmes and data that are necessary for the verification of compliance with the applicable type certification basis, OSD certification basis and environmental protection requirements, as defined in the certification programme. (B)     Approval of the technical content (completeness, technical accuracy, etc.), including any subsequent revisions of the manuals to be approved by EASA (aircraft flight manual (AFM), airworthiness limitations section of the instructions for continued airworthiness (ICA), and certification maintenance requirements (CMRs) document, where applicable). (iv)     Airworthiness function The airworthiness function is commonly performed by the Office of Airworthiness and should cover the following tasks as relevant\*: (A)     liaison between the design organisation (DO) and EASA with respect to all aspects of the certification programme; (B)     ensuring that a handbook and the flight test operations manual, when relevant, are prepared and updated as required by point [21.A.243](#_DxCrossRefBm1649097316); (C)     cooperation with EASA in developing procedures to be used for the type certification process; (D)     issuing of guidelines for documenting compliance; (E)     cooperation in issuing guidelines for the preparation of the manuals that are required by the applicable requirements, service bulletins (SBs), drawings, specifications, and standards; (F)     ensuring procurement and distribution of the applicable type certification basis, OSD certification basis, as well as environmental protection requirements and other specifications; (G)     cooperating with EASA in proposing the type certification basis, OSD certification basis, and environmental protection requirements; (H)     the interpretation of the type certification basis, OSD certification basis, and environmental protection requirements, and requesting EASA to take decisions in case of doubt; (I)      advising all the departments of the DO on any question regarding airworthiness, operational suitability, environmental protection approvals, and certification; (J)      the preparation of the certification programme, including a proposal for EASA involvement in the verification of compliance demonstration activities and data, and coordination of all the tasks related to the certification process in agreement with EASA; (K)     regular reporting to EASA about the progress of the certification process, including any difficulty or event that may necessitate a change of the previously notified EASA level of involvement, and announcing scheduled activities (e.g. tests) in due time; (L)      ensuring cooperation in preparing the inspection and test programmes needed for demonstration of compliance; (M)    establishing the compliance checklist and updating it with any changes; (N)     checking that all the compliance documents that are necessary to demonstrate compliance with the type certification basis, OSD certification basis, and environmental protection requirements are prepared and complete, and signing the documents for release; (O)     checking the required type design definition documents that are described in point [21.A.31](#_DxCrossRefBm1649096925) and ensuring that they are provided to EASA for approval when required; (P)     preparation, if necessary, of a draft of a type certification data sheet (TCDS) and/or a modification to a TCDS; (Q)     providing verification to the HDO that all the activities that are required for the certification process have been properly completed; (R)     managing the exercise of the DO privileges in accordance with point [21.A.263](#_DxCrossRefBm1649096918)(c); (S)     monitoring significant events on other aeronautical products, as far as they are relevant, to determine their effect on the airworthiness or operational suitability of the products that are designed by the DO; (T)     ensuring that there is cooperation in preparing SBs and the structural repair manual, and any subsequent revisions, with special attention to the manner in which the contents affect airworthiness and environmental protection, and granting the approval on behalf of EASA; (U)     ensuring the initiation of activities in response to a failure (accident/incident/in-service occurrence) evaluation and to complaints from the operation, and providing information to EASA if airworthiness or operational suitability are impaired (continuing airworthiness and continued operational suitability); (V)     advising EASA on the issuing of airworthiness directives in general based on SBs; and (W)    ensuring that the manuals that are approved by EASA, including any subsequent revisions, (AFM, airworthiness limitations section of the ICA, and CMR document, where applicable) are checked, to determine whether they meet their respective requirements, and that they are provided to EASA for approval. \* Some of the above tasks may be carried out through a different organisational function. (v)      Maintenance and operating instructions (A)     Ensuring the preparation and updating of all the maintenance and operating instructions (including ICA and SBs) that are needed to maintain airworthiness (i.e. continuing airworthiness) in accordance with the relevant certification specifications (CSs). For that purpose, the applicant should: (a)      establish the list of all the documents they produce to comply with CS 2X.1581 (CS 23.2620) and with the Appendix that is referred to in CS 2X.1529, CS‑E 20/25, or CS‑P 30/40, or CS 23.2625; (b)     establish a system to collect in-service experience to be used for the improvement of the instructions; and (c)      define the procedures and the organisation for producing and issuing those documents, taking into account the obligation of point [21.A.265](#_DxCrossRefBm1649096943)(h); those procedures should cover the following elements: (1)     preparation, including format and language (available industrial standards can be referred to and used); (2)     proofreading (checking for clarity, readability, typos, etc.); (3)     verification of technical consistency with the corresponding approved change(s), repair(s), or approved data, including effectivity, description, effects on airworthiness and environmental protection, especially when limitations are changed; (4)     verification of feasibility in practical applications, when relevant and feasible; and (5)     responsibilities and authorised signatories. Note: Compliance verification, as described in point (c)(1)(iii) of this AMC, applies to the manuals that are approved by EASA (AFM, airworthiness limitations section of the ICA, and CMR document, where applicable); for the other ICA or other maintenance instructions, the procedure that is required by (c)(1)(v) of this AMC provides a sufficient level of verification and does not require specific compliance verification unless, as per point [21.A.90C](#_DxCrossRefBm1649097034), additional work to demonstrate compliance is required; in that case, where additional compliance demonstration is required, points [21.A.91](#_DxCrossRefBm1649096897) to [21.A.109](#_DxCrossRefBm1649097032), as well as the independent checking function of compliance demonstration as per point [21.A.239](#_DxCrossRefBm1649096880)(b), apply. (B)     In accordance with points [21.A.6](#_DxCrossRefBm1649096931) and [21.A.7](#_DxCrossRefBm1649096932) and, where applicable, point [21.A.609](#_DxCrossRefBm1649097335), ensuring that those documents are made available as per point [21.A.7](#_DxCrossRefBm1649096932)(b). (vi)     Operational suitability data (A)     Ensuring the preparation and updating of all OSD in accordance with the relevant CSs. For that purpose, the applicant should: (a)      establish the list of all the documents that they produce to comply with CS-MMEL or CS-GEN-MMEL, CS-FCD, CS-CCD, CS-SIMD, and CS‑MCSD, as applicable; and (b)     define the procedures and the organisation for producing and issuing those documents, taking into account the obligation of point [21.A.265](#_DxCrossRefBm1649096943)(h); those procedures should cover the aspects that are described in (c)(1)(v)(A). (B)     In accordance with points [21.A.6](#_DxCrossRefBm1649096931), [21.A.62](#_DxCrossRefBm1649097022), [21.A.108](#_DxCrossRefBm1649097088), and [21.A.120B](#_DxCrossRefBm1649097105), ensuring that those documents are provided to all the affected operators and training organisations, as well as to all the authorities involved. ##### AMC1 21.A.239(d) Design management system *ED Decision 2025/016/R* **DESIGN ASSURANCE ELEMENT** (a) Reserved (b) Reserved (c) Design assurance system The complete design process, starting with the type certification basis, operational suitability data (OSD) certification basis, as well as environmental protection requirements and product specifications, and culminating with the issuing of a type certificate (TC), is shown in Figure 1, which identifies the relationships between the design, the certification, and the design assurance processes. Effective design assurance requires a continuing evaluation of all the factors that affect the adequacy of the design for the intended applications. In particular, it should be ensured that the product or part complies with the applicable type certification basis, OSD certification basis, and environmental protection requirements, and that it will continue to comply after any change to the TC or any repair. Planned and systematic tasks should therefore be defined and performed from the very beginning of the design activities up to the continued-airworthiness activities.  **Figure 1 — RELATIONSHIPS’ CONCEPT IN DESIGN AND CERTIFICATION** (1) Planned and systematic tasks For design organisations that carry out the certification process of products, their planned and systematic tasks should cover the following, and the related procedures should be defined accordingly. (i) General (A) Issue or, where applicable, supplement, or amend the handbook in accordance with point [21.A.243](#_DxCrossRefBm485230808), in particular to indicate the initiation of design activities on a product. (B) Assure that all the instructions of the handbook are adhered to. (C) Conduct the certification process. (D) Nominate staff as ‘compliance verification engineers’ that are responsible for approving compliance documents as defined in point (c)(1)(iii). (E) Nominate staff that belong to the Office of Airworthiness and are responsible as defined in point (c)(1)(iv). (F) In the case of an applicant for an STC, obtain the agreement of the TC holder for the proposed supplemental type certificate (STC) to the extent that is defined in point [21.A.115](#_DxCrossRefBm485230347). (G) Ensure that there is full and complete liaison between the design organisation and the related organisations that have responsibility for the products and parts that are manufactured according to the type design. (H) Provide assurance to EASA that any prototype models and test specimens adequately conform to the type design (see point [21.A.33](#_DxCrossRefBm485230474)(c). (ii) Head of the design organisation (or deputy) The head of the design organisation (HDO), or an authorised representative, should sign a declaration of compliance (see points [21.A.20](#_DxCrossRefBm485230342)(d) and [21.A.97](#_DxCrossRefBm485230488)(b)(3)) with the applicable type certification basis, OSD certification basis, and environmental protection requirements after verifying the satisfactory completion of the certification process. In accordance with point [21.A.20](#_DxCrossRefBm485230342)(e), the signature of the HDO on the declaration of compliance confirms that the procedures as specified in the handbook have been followed (see also [GM 21.A.265(b)](#_DxCrossRefBm485230828)). (iii) Compliance verification (A) Approval through the signing of all the compliance documents, including test programmes and data that are necessary for the verification of compliance with the applicable type certification basis, OSD certification basis and environmental protection requirements, as defined in the certification programme. (B) Approval of the technical content (completeness, technical accuracy, etc.), including any subsequent revisions of the manuals to be approved by EASA (aircraft flight manual (AFM), airworthiness limitations section of the instructions for continued airworthiness (ICA), and certification maintenance requirements (CMRs) document, where applicable). (iv) Airworthiness function The airworthiness function is commonly performed by the Office of Airworthiness and should cover the following tasks as relevant\*: (A) liaison between the design organisation (DO) and EASA with respect to all aspects of the certification programme; (B) ensuring that a handbook and the flight test operations manual, when relevant, are prepared and updated as required by point [21.A.243](#_DxCrossRefBm485230808); (C) cooperation with EASA in developing procedures to be used for the type certification process; (D) issuing of guidelines for documenting compliance; (E) cooperation in issuing guidelines for the preparation of the manuals that are required by the applicable requirements, service bulletins (SBs), drawings, specifications, and standards; (F) ensuring procurement and distribution of the applicable type certification basis, OSD certification basis, as well as environmental protection requirements and other specifications; (G) cooperating with EASA in proposing the type certification basis, OSD certification basis, and environmental protection requirements; (H) the interpretation of the type certification basis, OSD certification basis, and environmental protection requirements, and requesting EASA to take decisions in case of doubt; (I) advising all the departments of the DO on any question regarding airworthiness, operational suitability, environmental protection approvals, and certification; (J) the preparation of the certification programme, including a proposal for EASA involvement in the verification of compliance demonstration activities and data, and coordination of all the tasks related to the certification process in agreement with EASA; (K) regular reporting to EASA about the progress of the certification process, including any difficulty or event that may necessitate a change of the previously notified EASA level of involvement, and announcing scheduled activities (e.g. tests) in due time; (L) ensuring cooperation in preparing the inspection and test programmes needed for demonstration of compliance; (M) establishing the compliance checklist and updating it with any changes; (N) checking that all the compliance documents that are necessary to demonstrate compliance with the type certification basis, OSD certification basis, and environmental protection requirements are prepared and complete, and signing the documents for release; (O) checking the required type design definition documents that are described in point [21.A.31](#_DxCrossRefBm485230416) and ensuring that they are provided to EASA for approval when required; (P) preparation, if necessary, of a draft of a type certification data sheet (TCDS) and/or a modification to a TCDS; (Q) providing verification to the HDO that all the activities that are required for the certification process have been properly completed; (R) managing the exercise of the DO privileges in accordance with point [21.A.263](#_DxCrossRefBm485230409)(c); (S) monitoring significant events on other aeronautical products, as far as they are relevant, to determine their effect on the airworthiness or operational suitability of the products that are designed by the DO; (T) ensuring that there is cooperation in preparing SBs and the structural repair manual, and any subsequent revisions, with special attention to the manner in which the contents affect airworthiness and environmental compatibility, and granting the approval on behalf of EASA; (U) ensuring the initiation of activities in response to a failure (accident/incident/in-service occurrence) evaluation and to complaints from the operation, and providing information to EASA if airworthiness or operational suitability are impaired (continuing airworthiness and continued operational suitability); (V) advising EASA on the issuing of airworthiness directives in general based on SBs; and (W) ensuring that the manuals that are approved by EASA, including any subsequent revisions, (AFM, airworthiness limitations section of the ICA, and CMR document, where applicable) are checked, to determine whether they meet their respective requirements, and that they are provided to EASA for approval. \* Some of the above tasks may be carried out through a different organisational function. (v) Maintenance and operating instructions (A) Ensuring the preparation and updating of all the maintenance and operating instructions (including ICA and SBs) that are needed to maintain airworthiness (i.e. continuing airworthiness) in accordance with the relevant certification specifications (CSs). For that purpose, the applicant should: (a) establish the list of all the documents they produce to comply with CS 2X.1581 (CS 23.2620) and with the Appendix that is referred to in CS 2X.1529, CS‑E 20/25, or CS‑P 30/40, or CS 23.2625; (b) establish a system to collect in-service experience to be used for the improvement of the instructions; and (c) define the procedures and the organisation for producing and issuing those documents, taking into account the obligation of point [21.A.265](#_DxCrossRefBm485230434)(h); those procedures should cover the following elements: (1) preparation, including format and language (available industrial standards can be referred to and used); (2) proofreading (checking for clarity, readability, typos, etc.); (3) verification of technical consistency with the corresponding approved change(s), repair(s) or approved data, including effectivity, description, effects on airworthiness and environmental compatibility, especially when limitations are changed; (4) verification of feasibility in practical applications, when relevant and feasible; and (5) responsibilities and authorised signatories. Note: Compliance verification, as described in point (c)(1)(iii) of this AMC, applies to the manuals that are approved by EASA (AFM, airworthiness limitations section of the ICA, and CMR document, where applicable); for the other ICA or other maintenance instructions, the procedure that is required by (c)(1)(v) of this AMC provides a sufficient level of verification and does not require specific compliance verification unless, as per point [21.A.90C](#_DxCrossRefBm485230525), additional work to demonstrate compliance is required; in that case, where additional compliance demonstration is required, points [21.A.91](#_DxCrossRefBm485230388) to [21.A.109](#_DxCrossRefBm485230523), as well as the independent checking function of compliance demonstration as per point [21.A.239](#_DxCrossRefBm485230370)(b), apply. (B) In accordance with points [21.A.6](#_DxCrossRefBm485230422) and [21.A.7](#_DxCrossRefBm485230423) and, where applicable, point [21.A.609](#_DxCrossRefBm485230827), ensuring that those documents are made available as per point [21.A.7](#_DxCrossRefBm485230423)(b). (vi) Operational suitability data (A) Ensuring the preparation and updating of all OSD in accordance with the relevant CSs. For that purpose, the applicant should: (a) establish the list of all the documents that they produce to comply with CS-MMEL or CS-GEN-MMEL, CS-FCD, CS-CCD, CS-SIMD, and CS‑MCSD, as applicable; and (b) define the procedures and the organisation for producing and issuing those documents, taking into account the obligation of point [21.A.265](#_DxCrossRefBm485230434)(h); those procedures should cover the aspects that are described in (c)(1)(v)(A). (B) In accordance with points [21.A.6](#_DxCrossRefBm485230422), [21.A.62](#_DxCrossRefBm485230513), [21.A.108](#_DxCrossRefBm485230579), and [21.A.120B](#_DxCrossRefBm485230596), ensuring that those documents are provided to all the affected operators and training organisations, as well as to all the authorities involved.