The Future of Advanced Air Mobility

FAA Clears the Way to Supersonic Aircraft Flight Tests in U.S. Airspace

The FAA took another step toward facilitating the development of civil supersonic aircraft with the release of a final rule on January 6 that clarifies procedures for obtaining special flight authorizations for flight testing beyond a speed of Mach 1.

Adopted largely as proposed in June 2019, the final rule outlines the information needed for applications of special flight authorization and designates the FAA program office that will process those applications. It also creates a more “user-friendly” format, the U.S. agency said. The rule further recognizes that supersonic flight testing could be used to gather noise data.

However, the rule does not lift the ban on supersonic flight over land. Nor does it represent a policy change; instead, the rule streamlines and simplifies access to the various information necessary for special flight authorizations.

FAA's willingness to facilitate flight tests could be a benefit to U.S. companies Boom and Aerion, which are both working to bring new supersonic aircraft to market. Boom is planning to flight test its XB-1 supersonic demonstrator to gather data that would be used in the development of the Mach 2.2 Overture airliner. Aerion is working on a private jet design called the AS2.

The FAA did revise language in the final rule involving the environmental review process. It had originally proposed language to clarify information necessary for the FAA to make a National Environmental Policy Act (NEPA) determination. However, after receiving comments, the agency found the language actually generated confusion.

“The proposed language providing more detail about what an applicant could submit was not intended to imply that FAA would forego independently evaluating the information or closely examining the environmental impacts on a proposed test area in determining whether to grant a particular special flight authorization,” the agency said. “The language was also not intended to imply shifting the burden of complying with NEPA to the applicant rather than the FAA.”

According to the FAA, a number of requests in comments surrounding the ability for more than one program to use a designated test site were received. In response, the FAA said the application process provides latitude for requesting such test sites, and added regulations do not limit a flight test area to one applicant. However, each applicant is expected to submit its own environmental information regarding a test site.

That comes as the FAA has reached an agreement with the state of Kansas establishing a supersonic flight-test corridor.

Meanwhile, the agency dismissed more general opposition from environmental groups and certain municipalities about possible harm supersonic operations could have on the environment. These arguments are outside the scope of the rule, the FAA maintained, adding the final rule does not permit regular supersonic operations.

However, in simplifying the approach for special issuance applications, the agency is helping pave a path toward the return of civil supersonic flight. It is one of several steps the FAA is taking, including working with international regulators, as well as developing a separate rulemaking altogether regarding takeoff and landing noise certification standards.

“Today’s action is a significant step toward reintroducing civil supersonic flight and demonstrates the [Transportation] Department’s commitment to safe innovation,” said U.S. Transportation Secretary Elaine Chao in announcing the release of the final rule.

“The FAA supports the new development of supersonic aircraft as long as safety parameters are followed,” added FAA Administrator Steve Dickson. “The testing of supersonic aircraft at Mach 1 will only be conducted following consideration of any impact to the environment.”