The FAA this month quietly published long-awaited guidance for the certification of powered-lift aircraft—the first new category of civil aircraft since helicopters were introduced in the 1940s.
Powered-lift models have characteristics of both airplanes and rotorcraft, which places the regulator in a bind when it comes to defining their airworthiness. But a new advisory circular (AC), dated July 18, gives powered-lift developers the blueprint to earn type, production, and airworthiness certification for their designs. So far, none have been greenlit for commercial use.
FLYING is first to report the AC’s publication in the FAA dynamic regulatory system.
“The FAA is streamlining the certification process for advanced air mobility [AAM] aircraft by releasing guidance for how manufacturers can meet the agency’s aircraft design and performance safety standards,” the agency said in a statement shared with FLYING. “It establishes a consistent, performance-based framework for manufacturers to follow. The FAA will carefully evaluate each proposed design to ensure it meets the agency’s rigorous standards.”
AAM comprises a range of new aircraft types, including electric vertical takeoff and landing (eVTOL) air taxis and cargo aircraft. Previously, manufacturers worked toward eVTOL type certification under Part 23 regulations for light aircraft. But the FAA in 2022 reversed course, instead opting to categorize them as powered-lift—a category that has existed since 1997 but for which airworthiness standards and operating rules were never developed—under FAR 21.17(b) regulations for special class aircraft.
The switch caught manufacturers—such as Archer Aviation and Joby Aviation, which received proposed airworthiness criteria for their eVTOL air taxis in 2022—by surprise. The new AC is intended to clarify the certification process.
Certifying Powered-Lift
The AC defines powered-lift as heavier-than-air aircraft that use “engine-driven lift devices” or engine thrust for vertical takeoff and landing and low-speed flight. For lift during horizontal flight, they use rigid airfoils such as wings.
Some powered-lift designs, including Joby and Archer’s, use wing-mounted tilting propellers that support different modes of flight. Compared to rotorcraft, they have the potential for higher speeds and duration during the enroute portion of flight.
The FAA in October published a special federal aviation regulation (SFAR) establishing powered-lift operational requirements and training and certification for pilots. The AC, though, tells manufacturers the specific standards their designs must meet.
The regulator said it developed the guidance based on its early work with Archer, Joby, and other powered-lift projects. It details airworthiness standards—drawing from portions of parts 23, 25, 27, 29, 31, 33, and 35—that the agency considers an acceptable means for complying with 21.17(b). These cover everything from flight performance to the design, safety, and testing of systems and structures.
The requirements are intended for aircraft with no more than six passengers, weight of 12,500 pounds or less, and battery-powered electric engines. But they are not the only means of compliance, and the AC gives the FAA discretion to enact stricter requirements for designs with unique features.
eVTOL developer Beta told FLYING that the AC is a major victory for the FAA and industry. It eliminates the need for special rulemaking, the company said, by allowing direct compliance with proposed requirements. In other words, the guidance shortens the runway to certification by cutting through red tape.
The manufacturer said the AC aligns with the October SFAR’s performance-based operational rules. The emphasis is a departure from the draft AC the FAA released in June 2024, which relied more on prescriptive design standards. It is one of many changes from the initial proposal that will allow developers to certify powered-lift models for a range of operations.
“The release of the Advisory Circular for Type Certification of Powered Lift Aircraft is a critical achievement, both for the FAA and for the industry. In addition to providing clear guidance, it is helping to create a more predictable path to certification for all eVTOL aircraft, while maintaining the high safety standards that are foundational to any certification project,” BETA said. “This is another important step forward in bringing the AAM industry to commercial operations, and our collective effort to maintain American leadership in aviation.”
Major Changes
The eVTOL developer estimated the AC contains 20 to 25 significant changes from the draft, many of which are intended to create design flexibility for manufacturers. The biggest, the company said, is the decoupling of “increased performance” requirements from commercial passenger-carrying operations.
The AC requires powered-lift designs to follow “essential performance” and/or increased performance standards in the case of a system failure. The latter contain more rigorous safety requirements. But whereas the draft guidance called for passenger-carrying models to apply for increased performance, the final version does not. That means manufacturers can choose to design to higher standards depending on the specific characteristics of their mission, rather than the use case.
Another major change is the way the AC approaches propeller certification.
The draft AC treated vertical lift and tilt propellers like any other Part 33 or 35-certified propeller. The final version, though, introduces new requirements for these props’ fatigue, damage tolerance, testing, and operational performance, as well as parts of engines that power them—even if they are type-certificated.
There are also a few updated technical requirements. Perhaps the most consequential is the removal of minimum speed stipulations. These are replaced with “flight profiles” that encompass not only speed but the associated maneuvers, procedures, and operational conditions for the most adverse scenario in each profile. That creates a broader range of applications for each powered-lift design.
The AC also considers flight profiles rather than safe speeds in the standards for minimum safe characteristics and warnings.
Another new provision creates stricter aeromechanical stability standards, requiring the elimination of ground and air resonance that can cause loss of control. Others establish provisions for engine and propeller testing, fire safety, and a list of “critical” parts—required for each manufacturer—that could have a catastrophic effect on the aircraft should they fail.
These changes are only the beginning. The AC further outlines the design and safety of powerplants, electric engines, propellers, and other systems and structures; flight performance and characteristics, including under IFR; cockpit interface and voice and data recorders; and instructions for continued airworthiness.
Future of Powered-Lift
The release of the AC gives powered-lift developers the tools to accelerate the certification process. Combined with the SFAR—which covers post-certification requirements—the industry has far more clarity than it did even one year ago.
Its publication comes amid a federal push to open the powered-lift floodgates. In June, for example, President Donald Trump signed an executive order creating the eVTOL integration pilot program (eIPP)—a three-year extension of an FAA effort to study beyond visual line of sight (BVLOS) drone flight. The eIPP will comprise five projects intended to produce data that could shape powered-lift regulations.
The Trump administration has further signalled support for autonomous drones, commercial spacecraft, and other privately developed advanced aircraft.
The FAA, meanwhile, in June signed an agreement with aviation regulators in Canada, Australia, New Zealand, and the U.K. to harmonize their eVTOL standards. The five-way partnership will see the regulators work to lower barriers to entry for powered-lift aircraft that at least one of them has certified. The collaboration could help the FAA adopt new standards that have already been scrutinized by another regulator.
The U.S. aviation authority earlier this week also finalized its Modernization of Special Airworthiness Certification (MOSAIC) rule, which expands the light sport aircraft category to electric and powered-lift designs.
Light sport pilots will not be able to fly powered-lift just yet. But the rule creates a streamlined certification pathway for models that meet certain requirements, such as a maximum of two seats.
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