Definition
AC Form 8050-1 is the official FAA application form used by an aircraft owner to register an aircraft with the United States. It is submitted to the FAA Aircraft Registration Branch (with the appropriate fee and evidence of ownership such as a bill of sale) to obtain a Certificate of Aircraft Registration. The pink copy of a completed AC Form 8050-1 serves as temporary authority to operate the aircraft within the United States while the permanent Certificate of Aircraft Registration is being processed.
Plain English
It's the FAA paperwork an owner fills out to officially register their aircraft. While the FAA processes it, the pink copy of the form acts as a short-term registration that lets the owner fly the aircraft inside the U.S. until the real registration certificate arrives.
Context Anchor
Seen when buying, registering, or checking the required documents for an aircraft before flight.
Derivation
The 'AC' stands for 'Aircraft' (an FAA form-numbering prefix used for civil aviation forms). The number 8050-1 is simply the FAA's internal form identifier. Knowing this helps a pilot recognize related forms in the 8050 series, such as AC Form 8050-2 (Aircraft Bill of Sale).
Why Pilots Care
An aircraft cannot be legally operated in the United States until this form has been submitted and the FAA has issued the Certificate of Aircraft Registration.
Intuition Check
Do not confuse AC Form 8050-1 with the aircraft’s registration certificate itself. It is the application for that certificate, though a proper copy may temporarily serve as proof that registration is in process.
Example Sentence 1
After buying the Cessna, the new owner mailed AC Form 8050-1 to the FAA in Oklahoma City and kept the pink copy in the aircraft as temporary authority to fly.
Example Sentence 2
Before the preflight inspection, the pilot confirmed the aircraft's registration certificate was on board and matched the details from AC Form 8050-1.