FAR 21.171 — Airworthiness Certificates

FAR 21.171 is a short "applicability" section that simply tells you what the rest of Subpart H covers. It states that this subpart prescribes the procedural requirements for the issue of airworthiness certificates.

In plain English: when an aircraft manufacturer or owner needs to obtain an airworthiness certificate from the FAA, the rules and procedures they must follow are found in this subpart of Part 21. Section 21.171 itself doesn't impose any specific duty — it just sets the scope.

Why it matters operationally:

• An airworthiness certificate is one of the required documents that must be on board your aircraft before flight.
• Knowing where the issuance procedures live (Part 21, Subpart H) helps you understand how the certificate in your aircraft was originally obtained and what category it was issued under.
• On a checkrole, examiners may trace required documents back to their regulatory origin — Part 21 is where airworthiness certification begins.