FAA Federal Aviation Regulations (FARS, 14 CFR)

(a) For each engine that cannot be adequately substantiated by endurance testing in accordance with §33.49, the applicant must conduct additional tests to establish that components are able to function reliably in all normally anticipated flight and atmospheric conditions.

(b) Temperature limits must be established for each component that requires temperature controlling provisions in the aircraft installation to assure satisfactory functioning, reliability, and durability.