Which certificate is issued by authorities when the aircraft conforms to its design?

The Type Certificate is issued by aviation authorities to validate that an aircraft design complies with all applicable regulations and standards. When an aircraft's design is evaluated and found to conform to the established safety and performance criteria, the Type Certificate serves as formal recognition of that compliance. This document is critical as it signifies that the design meets the requirements necessary for airworthiness and is approved for production.

A Type Certificate encompasses all the specifications regarding the aircraft’s design—including design features, performance capabilities, and limitations—and ensures that any aircraft built under that certificate will maintain the design characteristics that were assessed and approved by the authorities.

In contrast, the Certificate of Airworthiness (C of A) relates to the condition of a specific aircraft once it is built, ensuring it is safe for flight at that moment. The Certificate of Conformity is typically used more for items in manufacturing to confirm that they match the specifications at production but does not convey the broader regulatory approval of the overall aircraft design. Supplemental Type Certificates (STC) allow for modifications to existing designs and do not represent the original design’s compliance, but rather changes made to it.