14 CFR § 21.601

This subpart prescribes—

Procedural requirements for issuing TSO authorizations;

Rules governing the holders of TSO authorizations; and

Procedural requirements for issuing letters of TSO design approval.

For the purposes of this subpart—

A TSO issued by the FAA is a minimum performance standard for specified articles used on civil aircraft;

A TSO authorization is an FAA design and production approval issued to the manufacturer of an article that has been found to meet a specific TSO;

A letter of TSO design approval is an FAA design approval for an article that has been found to meet a specific TSO in accordance with the procedures of § 21.621;

An article manufactured under a TSO authorization, an FAA letter of acceptance as described in § 21.613(b), or an article manufactured under a letter of TSO design approval described in § 21.621 is an approved article for the purpose of meeting the regulations of this chapter that require the article to be approved; and

An article manufacturer is the person who controls the design and quality of the article produced (or to be produced, in the case of an application), including any related parts, processes, or services procured from an outside source.