FAR 23.2260 — Materials and Processes
FAR 23.2260 sets standards for material suitability, fabrication processes, and design values used in Part 23 small airplane certification.
In Plain English
FAR 23.2260 governs how aircraft manufacturers (the applicants) prove that the materials and manufacturing processes used in a Part 23 small airplane are safe and reliable. While pilots don't apply this rule directly, understanding it helps you appreciate why your airplane's structure can be trusted.
Key requirements:
- Material suitability and durability: Materials in parts whose failure could prevent continued safe flight and landing must be proven suitable for expected environmental conditions in service.
- Sound fabrication: Manufacturing methods must consistently produce sound structures. Processes requiring close control must follow an approved process specification.
- Design values: Must reflect material strength probabilities that account for how critical the structural element is, including variability between material samples.
- Statistical testing: When strength properties matter, design values must be set based on enough tests to establish them statistically.
- Thermal effects: If heat significantly affects a critical component under normal operations, those effects on allowable stresses must be determined.
- Higher design values may be used if each item is individually tested, or if the Administrator approves alternative values.
Operationally, this rule is the reason your airframe behaves predictably across temperatures, humidity, and load cycles.
Regulation Text
14 CFR § 23.2260§ 23.2260 Materials and processes.
(a) The applicant must determine the suitability and durability of materials used for parts, articles, and assemblies, accounting for the effects of likely environmental conditions expected in service, the failure of which could prevent continued safe flight and landing.
(b) The methods and processes of fabrication and assembly used must produce consistently sound structures. If a fabrication process requires close control to reach this objective, the applicant must perform the process under an approved process specification.
(c) Except as provided in paragraphs (f) and (g) of this section, the applicant must select design values that ensure material strength with probabilities that account for the criticality of the structural element. Design values must account for the probability of structural failure due to material variability.
(d) If material strength properties are required, a determination of those properties must be based on sufficient tests of material meeting specifications to establish design values on a statistical basis.
(e) If thermal effects are significant on a critical component or structure under normal operating conditions, the applicant must determine those effects on allowable stresses used for design.
(f) Design values, greater than the minimums specified by this section, may be used, where only guaranteed minimum values are normally allowed, if a specimen of each individual item is tested before use to determine that the actual strength properties of that particular item will equal or exceed those used in the design.
(g) An applicant may use other material design values if approved by the Administrator.
Oral Exam Questions a DPE Might Ask
Q1What does FAR 23.2260 require regarding materials used in critical structural parts?
Per FAR 23.2260(a), the applicant must determine the suitability and durability of materials in parts whose failure could prevent continued safe flight and landing, accounting for environmental conditions expected in service.
Q2How are design values for material strength established under Part 23?
Under FAR 23.2260(c) and (d), design values must account for the criticality of the structural element and material variability, and must be based on sufficient tests of specification-compliant material to establish values on a statistical basis.
Q3When can an applicant use design values higher than the normal guaranteed minimums?
FAR 23.2260(f) allows higher design values if each individual specimen is tested before use to confirm its actual strength meets or exceeds the design value, and FAR 23.2260(g) permits other values if approved by the Administrator.
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Related Sections in Part 23