The Federal Aviation Administration (FAA) has published a new guide for the certification of powered-lift aircraft, including electric vertical take-off and landing aircraft (eVTOLs). Advisory Circular (AC) No. 21.17-4 was published on July 18.
“This AC establishes a more efficient path in designating the type certification basis for certain powered-lift projects, as the FAA will not need to announce the criteria for each project in the Federal Register for notice and comment for those designs for which the FAA has deemed it appropriate to use the criteria in this AC with no additions or changes”.
Until now, the FAA published airworthiness criteria for each project seeking type certification for eVTOL aircraft. Although the document is a guide and not an obligation, the expectation is that it should speed up the development of new projects and their respective certifications.
According to the AC, the airworthiness criteria incorporate an “essential performance” approval, as well as an optional “increased performance” approval with greater aircraft performance capability requirements. Applicants must meet either the essential or increased performance requirements. Alternatively, applicants may propose designs that are approved for both essential and increased performance with appropriate and different operating limitations.