14 CFR § 21.33

Each applicant must allow the FAA to make any inspection and any flight and ground test necessary to determine compliance with the applicable requirements of this subchapter. However, unless otherwise authorized by the FAA—

No aircraft, aircraft engine, propeller, or part thereof may be presented to the FAA for test unless compliance with paragraphs (b)(2) through (b)(4) of this section has been shown for that aircraft, aircraft engine, propeller, or part thereof; and

No change may be made to an aircraft, aircraft engine, propeller, or part thereof between the time that compliance with paragraphs (b)(2) through (b)(4) of this section is shown for that aircraft, aircraft engine, propeller, or part thereof and the time that it is presented to the FAA for test.

Each applicant must make all inspections and tests necessary to determine—

Compliance with the applicable airworthiness, aircraft noise, fuel venting, and exhaust emission requirements;

That materials and products conform to the specifications in the type design;

That parts of the products conform to the drawings in the type design; and

That the manufacturing processes, construction and assembly conform to those specified in the type design.