Authority
FAA
Applicability
FAA type, production and airworthiness certification of powered-lift. Appendix A provides airworthiness criteria the FAA identifies as an acceptable, but not the only, means of showing compliance with 14 CFR 21.17(b) for certain powered-lift.
Status
Current
Plain-English Explainer
FAA Advisory Circular 21.17-4 is the agency's dedicated certification guidance for powered-lift. It addresses type, production and airworthiness certification and includes powered-lift airworthiness criteria in Appendix A.
For US eVTOL programmes pursuing powered-lift certification, this is one of the clearest public descriptions of how the FAA expects applicants to structure certification work under 14 CFR 21.17(b).
An advisory circular is guidance, not a regulation. The FAA describes the Appendix A criteria as an acceptable means, but not the only means, of showing compliance for the powered-lift covered by the AC.
