Every US-registered aircraft carries two separate documents, and it is common for buyers to assume one covers what the other actually does. They answer different questions.
Registration: "who owns this, and is it on the registry"
The Certificate of Aircraft Registration (AC Form 8050-3) records ownership. It confirms the aircraft is entered on the FAA's civil registry under a specific N-number, held by a specific registered owner. It has nothing to do with whether the airplane is mechanically sound or legal to operate — an aircraft can be validly registered and be nowhere near airworthy.
Airworthiness: "is this legal to fly, and in what category"
The Airworthiness Certificate (AC Form 8100-2) is issued once, when the aircraft is first found to conform to its approved design and to be in condition for safe operation. It generally does not expire on its own — what keeps it valid is the aircraft continuing to be maintained in accordance with FAA rules. There are two broad categories worth knowing:
- Standard airworthiness — normal, utility, acrobatic, transport, and similar categories for aircraft built and maintained to a type-certificated design. Most production general aviation aircraft.
- Special airworthiness — covers experimental, light-sport, restricted, and similar categories, each with its own operating limits. An aircraft in this category can be a perfectly legitimate, well-built airplane — it is simply certificated under different rules, which affects things like what maintenance can be performed and by whom.
Why the distinction matters when buying
Confirming registration tells you the seller is who the paperwork says they are. Confirming airworthiness category tells you what kind of aircraft you are actually buying and what rules apply to flying and maintaining it — an experimental amateur-built aircraft is not a bad thing, but it is a different thing than a standard-category production airplane, and the two should never be assumed interchangeable.
Both records trace back to the same N-number. Our free lookup and $79 report pull the FAA registration data — including certification category — alongside the accident and filing history, so you see ownership, category, and history together instead of chasing three separate lookups.