Airworthiness, Certification and Approved Data

An aircraft is airworthy when it holds a valid type certificate, complies with every applicable airworthiness directive, is maintained to current approved data, and has a release to service signed by a person holding the necessary authorisation. Appearance and condition are irrelevant to that definition — a spotless aircraft with an overdue directive is unairworthy.

Approved data comes from the type certificate holder and includes the maintenance manual, the illustrated parts catalog, wiring diagrams, structural repair instructions, service bulletins, service instructions and the airworthiness directives that override them. Maintenance performed to any other data may only be returned to service through the approved data or under the authority’s repair and alteration rules, which in the United States means an inspection authorisation holder or a certificated repair station.

A major repair or alteration is one that affects strength, rigidity, shape, size or flight characteristics, and it must be performed to approved data and recorded on the authority’s prescribed form. Replacement parts must carry approval markings: a parts manufacturer approval, a type certificate holder or PMA approval, or a standard part listed in the applicable specification.

Retention is not optional. Total time, life-limited part status, airworthiness directive compliance, major repair and alteration records, and every maintenance entry are retained for the life of the aircraft and cannot be discarded when it is sold. A digital record set must be at least as attributable, durable and reviewable as the paper it replaces.