21.165—Responsibility of holder.
The holder of a production certificate shall—
(a)
Maintain the quality control system in conformity with the data and procedures approved for the production certificate; and
(b)
Determine that each part and each completed product, including primary category aircraft assembled under a production certificate by another person from a kit provided by the holder of the production certificate, submitted for airworthiness certification or approval conforms to the approved design and is in a condition for safe operation.
Code of Federal Regulations
Pt. 21, Subpt. G, Nt.