AMC 25.603(b) Suitability and durability of materials -- Approved material specifications and material process specifications

• ED Decision 2021/015/R found in: CS-25 Amdt 27 - Large Aeroplanes (Jan 2023)

AMC 25.603(b) Suitability and durability of materials — Approved material specifications and material process specifications ED Decision 2021/015/R The approved material specifications and material process specifications should: — be suitable for the application; — define material and material process controls; — include requirements to assist the applicant in managing raw/feedstock/unfinished materials, as appropriate to the technology (e.g. the feedstock powder used in additive manufacturing, or matrix systems used in pre-impregnated composites). The material strength and other properties that are used in design data (including fatigue and damage tolerance characteristics, when applicable) are governed by, and can be significantly sensitive to, the related variables of the material production process (including raw-material considerations). Furthermore, these properties may also be influenced by other higher-level fabrication processes (manufacturing and assembly), including other post-processing activities (e.g. adhesive material and bonding properties produced in a bonded joint of a complex part may not be the same as those produced in a test coupon). The material specifications, material process specifications, and/or production drawings should identify key characteristics and parameters to be monitored by in-process quality control, including the acceptable limits to the characteristics of materials and processes (e.g. acceptable anomalies or flaws), and should address anisotropy, when applicable. This information may also help applicants identify other defect types and damage modes than the anomalies and flaws that are accepted under the specifications, including those that may occur in service. Such data may be used to help applicants show compliance with other specifications, e.g. [CS 25.571](#_DxCrossRefBm1709820942). However, showing compliance with [CS 25.571](#_DxCrossRefBm1709820942) does not relieve from the requirement for material process controls. Note: approved material specifications and approved material process specifications can be, for example, industry or military specifications, or European Technical Standard Orders (ETSOs). [Amdt No: 25/27]