14 C.F.R. § 33.23 Engine mounting attachments and structure.
Title 14 - Aeronautics and Space
(a) The maximum allowable limit and ultimate loads for engine mounting attachments and related engine structure must be specified. (b) The engine mounting attachments and related engine structure must be able to withstand— (1) The specified limit loads without permanent deformation; and (2) The specified ultimate loads without failure, but may exhibit permanent deformation. [Amdt. 33–10, 49 FR 6851, Feb. 23, 1984]
Title 14: Aeronautics and Space
PART 33—AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES
Subpart B—Design and Construction; General
§ 33.23 Engine mounting attachments and structure.

