Type certificate

Certification confirms that the aircraft of a new type intended for serial production is in compliance with applicable airworthiness requirements established by the national air law.

The TC reflects a determination made by a regulatory authority that the type design is in compliance with airworthiness requirements.

[3] The TC implies that aircraft manufactured according to the approved design can be issued an airworthiness certificate.

For example, in the U.S. these sub-assemblies must meet requirements in the applicable Technical Standards Order (TSO).

A CoA is issued for each aircraft that is properly registered if it conforms to its type design and ready for safe operation.

The CoA is valid and the aircraft may be operated as long as it is maintained in accordance with the rules issued by the regulatory authority.

After investigations by the regulator, the final approval of such documents (after the required comments and amendments in order to fulfill the laws), becomes the basis of the certification.

Tests may also cover different environments - high and low altitude, freezing and hot climates, and so on, to confirm correct performance throughout the aircraft's design envelope.

In parallel with aircraft testing, the applicant firm also draws up maintenance program to support continuous airworthiness after approval of the design.

[1] Other continuing airworthiness activities include additional tasks associated with the maintenance program and design changes to be accomplished via: Sometimes during service, the aircraft may encounter problems that may compromise the aircraft's safety, which are not anticipated or detected in prototype testing stages.

The directives normally consists of additional maintenance or design actions that are necessary to restore the type's airworthiness.

ADs are used by the certifying authority to notify aircraft owners and operators of unsafe conditions and to require their correction.

ADs prescribe the conditions and limitations, including inspection, repair, or alteration under which the product may continue to be operated.

These improvements (normally involving some alterations) are suggested through service bulletins to an aircraft owners/operators as optional (and may be extra cost) items.

The owner/operator shall exercise their discretion whether or not to incorporate the bulletins and report the decision to the regulatory authority of the state of the aircraft registry.

For example, increasing (or decreasing) an aircraft's flight performance, range and load carrying capacity by altering its systems, fuselage, wings or engines resulting in a new variant may require re-certification.

Any additions, omissions or alterations to the aircraft's certified layout, built-in equipment, airframe and engines, initiated by any party other than the type certificate holder, need an approved supplementary ("supplemental" in FAA terminology) type certificate, or STC.

Before STCs are issued, procedures similar to type certificate changes for new variants are followed, likely including thorough flight tests.