Definition
A federal regulation that prohibits operating a civil aircraft unless it carries an appropriate and current airworthiness certificate and a registration certificate issued to its owner. The airworthiness certificate must be displayed at the cabin or cockpit entrance so it is legible to passengers or crew.
Plain English
This is the rule that says you can't fly an aircraft unless two specific paper certificates are on board: one showing the aircraft is legal to fly, and one showing who owns it. The airworthiness certificate also has to be posted somewhere people can see it when they board.
Context Anchor
Seen during preflight paperwork checks, especially when verifying that the aircraft documents are on board and current before flight.
Derivation
14 CFR means Title 14 of the Code of Federal Regulations, which contains all U.S. aviation rules. Part 91 covers general operating and flight rules for civil aircraft. Section 91.203 is the specific paragraph within that part dealing with required certificates. The numbering works like an address: title, part, section.
Why Pilots Care
Missing or expired documents make the flight illegal and can lead to enforcement action or grounding.
Intuition Check
Do not read this as just a handbook reference or page number. It is a legal rule citation: it points to an enforceable FAA regulation that applies before the aircraft is operated.
Example Sentence 1
During preflight, the pilot confirmed the airworthiness and registration certificates were on board and properly displayed, as required by 14 CFR part 91, section 91.203.
Example Sentence 2
During the ramp check the inspector requested the certificates required by 14 CFR part 91, section 91.203.