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Question

Is it required that the Manufacturer’s Design Report be certified by a Certifying Engineer as stated in 2.3.3.1(a)(2)? 

Answer

Certification by a Certifying Engineer is not required in this case.

Paragraph 4.15.4.1(b) states that “Localized stresses at the skirt attachment location may be evaluated by the design by analysis methods in Part 5.” If the designer goes to Part 5 to satisfy a supplemental requirement in Part 4, certification rules of 2.3.3.1 do not apply. Paragraph 2.3.3.1(a)(2) states that the use of Part 5 to establish design thickness, where rules are not provided in Part 4, requires a Certifying Engineer. In this case, the Part 5 evaluation is an additional check of localized stresses but not used to establish design thickness.