Appendix J to GM 21.A.101 Definitions and terminology

• ED Decision 2019/018/R found in: Initial Airworthiness and Environmental Protection (748/2012) Part-21 Part-21L (Jul 2024)

Appendix J to GM 21.A.101  Definitions and terminology ED Decision 2019/018/R J.1     Aeronautical product. The terms ‘aeronautical product’ or ‘product’ used in this guidance material include type-certified aircraft, engines, or propellers and, for the purpose of this GM, an ETSOA’d APU. J.2     Assumptions used for certification. The assumptions used for certification are the evaluations and decisions that led to the approval of the baseline product’s characteristics. Examples of the product’s baseline characteristics include but are not limited to the following: — Design methodologies, methods of compliance, and standards used to achieve compliance with the certification specifications making up the certification basis; — Structural, mechanical, electrical, propulsion, aerodynamic, performance, operational, and maintenance characteristics; — Operational and flight envelopes defining the product performance and capabilities at specified weights, speeds, altitudes, load factors, and centres of gravity; — Crashworthiness; — Role or mission; — Airworthiness and operational limitations; or — Pilot training, if necessary. J.3     Baseline product. It is an aeronautical product with a specific, defined approved configuration and certification basis that the applicant proposes to change. J.4     Certification basis. The combination of the: — airworthiness certification specifications as provided for in point [21.B.80](#_DxCrossRefBm1649096853); — OSD certification specifications as provided for in point [21.B.82](#_DxCrossRefBm1649096972); and — environmental protection requirements, as provided for in point [21.B.85](#_DxCrossRefBm1649096971), and as established for the change according to point [21.A.101](#_DxCrossRefBm1649096998), as well as the: — special conditions; — equivalent safety findings; — elects to comply; and — deviations, applicable to the product to be certified. J.5     Change. The term ‘change’ refers to a change to a product type certificate (as defined in point [21.A.41](#_DxCrossRefBm1649097019)) approved or to be approved under Subpart D or Subpart E (as a supplemental type certificate) of Part 21, including a change to an STC or a change to the ETSOA for auxiliary power units (APUs) under Subpart O. A change may consist of a single stand-alone change to one TC component or several interrelated changes to different TC components (e.g. the type design, operating characteristics, OSD, environmental protection characteristics, etc. (see point [21.A.41](#_DxCrossRefBm1649097019) and [GM to 21.A.90A](#_DxCrossRefBm1649097030))). J.6     Design change. The term ‘design change’ refers to a change to the type design (as defined in point [21.A.31](#_DxCrossRefBm1649096925)) of an aeronautical product. In the context of this document, the terms ‘change to the type design’, ‘modification’, ‘design change’, and ‘type design change’ are synonymous. J.7     Earlier standards. The certification specifications or previous standards in effect prior to the date of application for the change, but not prior to the existing certification basis. J.8     Existing certification basis. The certification specifications or previous standards incorporated by reference in the type certificate of the baseline product to be changed. J.9     Latest standards. The certification specifications in effect on the date of application for the change. J.10   Previous relevant design changes. Previous design changes, the cumulative effect of which could result in a product significantly or substantially different from the original product or model, when considered from the last time the latest standards were applied. J.11   Product-level change. A change or combination of changes that makes the product distinct from other models of the product (e.g. range, payload, speed, design philosophy). Product-level change is defined at the aircraft, aircraft engine, or propeller level of change. J.12   Secondary change. A change that is part of a significant physical change that does not contribute materially to the level of safety. Guidance is contained in paragraph 3.10.1.4 of this GM. J.13   Significant change. A change to the type certificate to the extent that it changes one or more of the following, but not to the extent to be considered a substantial change: the general configuration, principles of construction, or the assumptions used for certification. The significance of the change is considered in the context of all previous relevant design changes and all related revisions to the applicable standards. Not all product-level changes are significant. J.14   Significant change to area. For aircraft excepted under point [21.A.101](#_DxCrossRefBm1649096998)(c) only: a change to an area is significant if the general configuration or the principles of construction in that area are not retained, or the assumptions used for the certification of that area do not remain valid. J.15   Substantial change. A change that is so extensive that a substantially complete investigation of compliance with the applicable certification basis is required, and consequently a new type certificate is required pursuant to point [21.A.19](#_DxCrossRefBm1649096992). ##### Appendix J to GM 21.A.101 Definitions and terminology *ED Decision 2019/018/R* **J.1** **Aeronautical product.** The terms ‘aeronautical product’ or ‘product’ used in this guidance material include type-certified aircraft, engines, or propellers and, for the purpose of this GM, an ETSOA’d APU. **J.2** **Assumptions used for certification****.** The assumptions used for certification are the evaluations and decisions that led to the approval of the baseline product’s characteristics. Examples of the product’s baseline characteristics include but are not limited to the following: — Design methodologies, methods of compliance, and standards used to achieve compliance with the certification specifications making up the certification basis; — Structural, mechanical, electrical, propulsion, aerodynamic, performance, operational, and maintenance characteristics; — Operational and flight envelopes defining the product performance and capabilities at specified weights, speeds, altitudes, load factors, and centres of gravity; — Crashworthiness; — Role or mission; — Airworthiness and operational limitations; or — Pilot training, if necessary. **J.3** **Baseline product****.** It is an aeronautical product with a specific, defined approved configuration and certification basis that the applicant proposes to change. **J.4** **Certification basis****.** The combination of the: — airworthiness certification specifications as provided for in point [21.B.80](#_DxCrossRefBm485230343); — OSD certification specifications as provided for in point [21.B.82](#_DxCrossRefBm485230463); and — environmental protection requirements, as provided for in point [21.B.85](#_DxCrossRefBm485230462), and as established for the change according to point [21.A.101](#_DxCrossRefBm485230489), as well as the: — special conditions; — equivalent safety findings; — elects to comply; and — deviations, applicable to the product to be certified. **J.5** **Change.** The term ‘change’ refers to a change to a product type certificate (as defined in point [21.A.41](#_DxCrossRefBm485230510)) approved or to be approved under Subpart D or Subpart E (as a supplemental type certificate) of Part 21, including a change to an STC or a change to the ETSOA for auxiliary power units (APUs) under Subpart O. A change may consist of a single stand-alone change to one TC component or several interrelated changes to different TC components (e.g. the type design, operating characteristics, OSD, environmental protection characteristics, etc. (see point [21.A.41](#_DxCrossRefBm485230510) and [GM to 21.A.90A](#_DxCrossRefBm485230521))). **J.6** **Design change****.** The term ‘design change’ refers to a change to the type design (as defined in point [21.A.31](#_DxCrossRefBm485230416)) of an aeronautical product. In the context of this document, the terms ‘change to the type design’, ‘modification’, ‘design change’, and ‘type design change’ are synonymous. **J.7** **Earlier standards****.** The certification specifications or previous standards in effect prior to the date of application for the change, but not prior to the existing certification basis. **J.8** **Existing certification basis****.** The certification specifications or previous standards incorporated by reference in the type certificate of the baseline product to be changed. **J.9** **Latest standards****.** The certification specifications in effect on the date of application for the change. **J.10** **Previous relevant design changes****.** Previous design changes, the cumulative effect of which could result in a product significantly or substantially different from the original product or model, when considered from the last time the latest standards were applied. **J.11** **Product-level change****.** A change or combination of changes that makes the product distinct from other models of the product (e.g. range, payload, speed, design philosophy). Product-level change is defined at the aircraft, aircraft engine, or propeller level of change. **J.12** **Secondary change****.** A change that is part of a significant physical change that does not contribute materially to the level of safety. Guidance is contained in paragraph 3.10.1.4 of this GM. **J.13** **Significant change****.** A change to the type certificate to the extent that it changes one or more of the following, but not to the extent to be considered a substantial change: the general configuration, principles of construction, or the assumptions used for certification. The significance of the change is considered in the context of all previous relevant design changes and all related revisions to the applicable standards. Not all product-level changes are significant. **J.14** **Significant change to area****.** For aircraft excepted under point [21.A.101](#_DxCrossRefBm485230489)(c) only: a change to an area is significant if the general configuration or the principles of construction in that area are not retained, or the assumptions used for the certification of that area do not remain valid. **J.15** **Substantial change****.** A change that is so extensive that a substantially complete investigation of compliance with the applicable certification basis is required, and consequently a new type certificate is required pursuant to point [21.A.19](#_DxCrossRefBm485230483).