Definition
An official document issued by the FAA (or equivalent civil aviation authority) that certifies an aircraft conforms to its approved type design and is in a condition for safe operation. It must be displayed in the aircraft and remains valid as long as the aircraft is maintained in accordance with the applicable airworthiness regulations.
Plain English
A legal document showing that the aircraft is built to an approved design and is safe to fly. It must be carried in the aircraft, and it stays valid only while the aircraft is properly maintained.
Context Anchor
Pilots encounter this during aircraft document checks, preflight preparation, inspections, rentals, and ramp checks.
Derivation
From Latin certificare, meaning 'to make certain,' combined with airworthy — literally 'worthy of the air,' meaning fit and safe to fly. So a Certificate of Airworthiness is a document that makes certain the aircraft is fit to fly.
Why Pilots Care
An aircraft may not be operated legally without a current Certificate of Airworthiness.
Intuition Check
Do not assume the certificate is a guarantee that the aircraft is safe right now. It is legal approval based on the aircraft meeting its design and maintenance requirements; the aircraft still must be checked before flight.
Example Sentence 1
During the preflight, the pilot confirmed the Certificate of Airworthiness was displayed in the cabin where passengers and inspectors could see it.
Example Sentence 2
After completing the annual inspection, the mechanic returned the aircraft to service with its Certificate of Airworthiness still in force.