Information relating to the design, maintenance, repair and safe operation of an individual aircraft or a fleet of aircraft.

The airworthiness of aircraft ranges from the initial approval of a new aircraft design to ensuring an aircraft’s on-going safety standards. Most approvals of new aircraft manufactured in Europe are undertaken by the European Aviation Safety Agency (EASA).  This enables manufacturers to gain one approval for the continent which is then recognised throughout the world. Aircraft built outside Europe would normally be certified by the regulatory authorities in the nation concerned.

It is then the responsibility of each national authority to oversee the continued safety standards of the aircraft registered in that country, for UK-registered aircraft (those whose registrations comprise of G- and then four letters) this responsibility falls to the CAA.

Every aircraft is provided with a Certificate of Airworthiness or Permit to Fly. Each time this is renewed the aircraft is inspected to ensure it complies with the relevant safety standards. Certain modifications or changes to aircraft also require approval to ensure they do not affect overall safety.

The operators of aircraft from outside the UK that wish to fly in UK airspace, but whose aircraft does not hold an internationally recognised Certificate of Airworthiness or Permit to Fly, must apply in advance to the CAA for permission. This is often the case for some amateur built and vintage aircraft.