Definition
AC Form 8050-1 is the official FAA Aircraft Registration Application used by an aircraft owner to register a U.S. civil aircraft with the FAA Aircraft Registry. It establishes the applicant's claim of ownership and, once accepted along with evidence of ownership and the registration fee, results in the issuance of a Certificate of Aircraft Registration (AC Form 8050-3).
Plain English
It is the paperwork an aircraft owner fills out to officially register their aircraft with the FAA. Submitting it -- along with proof that they own the aircraft and the required fee -- is what gets them their registration certificate.
Context Anchor
You will see this term when studying aircraft documents, buying or selling an aircraft, or checking whether an aircraft has proper registration paperwork.
Derivation
"AC" stands for Advisory Circular-style FAA form numbering used by the Aircraft Registry. The form number itself (8050-1) is simply the FAA's filing identifier -- knowing the number helps when ordering, mailing, or referencing the correct document.
Why Pilots Care
An aircraft cannot be operated legally until this form has been approved and the registration certificate issued.
Intuition Check
Do not assume the application is the final registration certificate. It is the request for registration; the certificate is the document the FAA issues after accepting the registration.
Example Sentence 1
After purchasing the Cessna, the new owner completed AC Form 8050-1 and mailed it to the FAA Aircraft Registry along with the bill of sale.
Example Sentence 2
Before the preflight inspection, the pilot confirmed that AC Form 8050-1 had been processed and the registration certificate was aboard.