It is a function of the Safety Regulation Group to issue Certificates of Airworthiness or permits to fly to allow aircraft to fly in compliance with the UK Air Navigation Order 2009. Implicit in this activity is the task of agreeing the standards to be applied, and that compliance with those standards has been shown in the particular case by the Applicant for the certificate or permit. A similar activity is required to approve modifications so that a Certificate of Airworthiness or permit may be issued or reinstated for a modified aircraft.
The Airworthiness Approval Note is a document which records the approval that the particular certificate or permit may be issued, (or reinstated following modification). In so doing the AAN provides a record of, (either directly or by reference to controlled documents), the build definition of the aircraft or modification, the standards that have been applied, the justification of compliance with those requirements, any restrictions or limitations affecting the approval, and a statement of approval.