Published date: 2 February 2022


This AC provides a means acceptable to the Director for showing compliance with Part 21 in order to gain a supplemental type certificate (STC).

The guidelines provided in this AC are general in nature and intended to help applicants and design organisations gain a better understanding of the STC process including their respective roles and responsibilities.

Related rules

Related rules

This AC relates specifically to Civil Aviation Rule Part 21 Subpart E – Supplemental Type Certificates.

Change notice

Revision 2 updates section 1.4 to introduce Appendix B. This appendix provides a new Project Specific Certification Plan (PSCP) template for projects that have a certification basis of the US Federal Aviation Administration (FAA) 14 Code of Federal Regulations (CFR) 23 Amendment 64 or later. This revision also updates the compliance matrix in Appendix A to streamline PSCP processing. Lastly, some grammatical and typographical errors have been corrected.

Note: As the excel tables in the two Appendices may be difficult to cut and paste from a PDF document, they are available here:

AC21-8, Design Changes - Supplemental Type Certificate, Appendix A, Revision 2 [XLSX 12 KB]

AC21-8, Design Changes - Supplemental Type Certificate, Appendix B, Revision 2 [XLSX 27 KB]