FAR 23.2265 — Special Safety Factors
FAR 23.2265 requires special safety factors for uncertain or variable Part 23 aircraft parts. Learn how it applies to design loads and certification.
FAR 23.2265 is a Part 23 airworthiness standard that tells aircraft designers when to apply an extra cushion — a special factor of safety — to certain structural parts. It matters because not every part can be analyzed with perfect confidence, and parts that wear out or vary in manufacturing need additional margin to stay safe in service.
The applicant (manufacturer) must determine a special factor of safety for each critical design value of any part, article, or assembly when:
- The critical design value is uncertain;
- The part is likely to deteriorate in service before normal replacement; or
- The part is subject to appreciable variability from manufacturing or inspection uncertainties.
In setting that factor, the applicant uses quality controls and specifications that account for the type of application, inspection method, structural test requirement, sampling percentage, and process and material control.
Finally, the highest pertinent special factor in the design must be multiplied by each limit and ultimate load — or by ultimate load alone where there is no corresponding limit load (for example, emergency condition loading).