Seeking certification


Joby Aviation is working with FAA to get its electric aircraft design certified in 2023 so that the company can begin ferrying passengers around major U.S. cities in 2024. Can the advanced air mobility company cross the finish line? Aaron Karp set out to find the answer.

Outside of public view, air taxi developer Joby Aviation began flying the first full-scale prototype of its four-passenger, piloted electric rotorcraft in 2017. Representatives from FAA were on-site in California to view the initial flights.

Santa Cruz-based Joby may not have been ready for the public to see the first version of its 2,177-kilogram S4, the six-propeller, battery-powered aircraft that company executives believe will ferry passengers around multiple major cities this decade. Yet, it was critical for FAA to be involved given that there is no future for Joby without receiving a type certificate from the agency verifying that its electric vertical takeoff and landing aircraft, or eVTOL, design complies with airworthiness standards. This is one of three certifications FAA must grant before Joby can begin producing S4s in large quantities and flying passengers.

As Joby appears closest of the eVTOL developers to achieving type certification, the company’s progress is being watched closely by other developers, traditional aerospace manufacturers, officials in large metropolitan areas where eVTOLs could operate, aviation regulators around the world and others. Certification could prove to be a turning point for the emerging industry and potentially pave the way for the other half-dozen or so well-funded air taxi developers seeking to gain regulatory approval for their passenger eVTOLs. But missing FAA’s marks could lead to skepticism about this entire future class of small electric aircraft.

“Joby has made the most progress so far among eVTOL developers toward certification,” Edison Yu, an analyst with Deutsche Bank who covers the eVTOL sector, told me in an interview. Yu authored a 48-page report, “Electrifying the sky,” released by Deutsche Bank in April, analyzing the efforts of Joby and two of its primary competitors, Archer Aviation of Palo Alto in California and Vertical Aerospace of Bristol in the U.K., to bring eVTOLs to market.

Yu believes those three companies are best positioned to achieve certification of a piloted, passenger eVTOL within the next two to three years, with Joby in the lead. This ranking differs slightly from that of the Advanced Air Mobility Reality Index that SMG Consulting of Arizona publishes monthly, though certification is just one factor in SMG’s ranking. The latest iteration puts Joby in first, Archer in sixth place and Vertical in 11th.

Yu says Joby earned the top spot in his report because it has “the highest performing aircraft across nearly all metrics” with “the best raw specs.” Joby says the S4 will operate up to distances of 240 kilometers and at speeds of up to 320 kph.

Another box the company has checked, according to Yu, is securing adequate funding — specifically $394 million from Toyota and $125 million from Uber, whose Elevate research and development division became part of Joby in 2020. Uber plans to incorporate Joby’s air taxis into its ride-sharing app. Also, last August, Joby raised upward of $1 billion in an initial public offering on the New York Stock Exchange. 

“Getting an aircraft through certification and into mass production will cost at least $500 million,” Yu says.

Joby, Archer and Vertical are relying on a similar concept for their aircraft designs: The eVTOLs would lift off with propellers, and then those propellers would be tilted for cruise. Yu says this is the best way to optimize performance but cautions the trade-off “is higher technological complexity,” which could make certification more complicated.

Existing regulations

A year after FAA officials witnessed the first flights of the S4 in 2017, the agency made a decision that greatly enhanced Joby’s prospects for getting the aircraft certified. FAA published a notice in the Federal Register that it would certify eVTOLs under existing regulations, rather than develop new standards. The aircraft would fit into FAA’s Part 23 airworthiness category used for small airplanes carrying fewer than 15 passengers, the agency said.

For novel technologies on eVTOLs, FAA said it would apply “special conditions” — but these will not require a certification process that substantially deviates from processes for certifying traditional airplanes and helicopters.

“Some [eVTOL] certifications could require the FAA to issue special conditions or additional airworthiness criteria, depending on the type of project,” FAA said in a written statement in response to my queries about Joby’s certification. “With regards to policies and procedures, the FAA’s current regulations allow aircraft to meet our strict safety standards in innovative ways,” the statement said in an apparent reference to the 2016 rewriting of Part 23 that made the regulations less prescriptive in the name of permitting the rapid modernization of general aviation designs. “We use the same data-driven approach when evaluating these complex systems that has created the safest aviation system in the world. We apply this methodical, process-oriented, safety-first approach to all aircraft.”

The flexibility inherent in Part 23 has paved the way for Joby’s potential certification of the S4, the company’s executives say.

“It lets us work in a modern certification path using standards and test procedures that are known quantities,” Greg Bowles, a former vice president for innovation at the Washington, D.C., and Brussels-based General Aviation Manufacturers Association and now Joby’s head of government affairs. “The core of our certification follows a methodology of various aerospace products previously certified.”

That’s a different approach than the one being taken by the European Union Aviation Safety Agency, EASA, which has declared all forms of VTOLs a new kind of aircraft for certification purposes. In an explanation on its website, EASA cites “the absence of suitable certification specifications” for eVTOLs for its decision, adding it has “developed a complete set of dedicated technical specifications,” released in 2019, providing a broad framework for how eVTOLs will be certified.

According to EASA, the agency “is now in the process of creating new rules and revising existing ones to address new technologies, operational air transport concepts, flight crew and operator licensing requirements” related to eVTOLs.

Traditionally, developers have gotten their aircraft initially certified in the market where they are based, with the intent of getting that certification recognized by other major aviation authorities around the world. But EASA’s designation of eVTOLs as novel could make it challenging for Vertical and other eVTOL developers that aim to operate their aircraft in European cities by the middle of this decade, such as Volocopter of Germany. Vertical plans to get its eVTOL certified first by the U.K. Civil Aviation Authority, but this would not be automatically accepted by EASA, as was the case before the U.K. left the European Union, and could limit the potential markets in which the aircraft can operate.

Vertical, which aims to sell its aircraft to airlines and other operators (as opposed to Joby, which plans to operate its own aircraft), has said it needs EASA’s signoff after CAA’s. It will therefore attempt to adhere to EASA standards during its U.K. certification.

The situation also makes it more difficult for Joby’s aircraft, if certified by FAA, to be recognized as certified by EASA. The two agencies usually largely accept the other’s judgment regarding aircraft certifications, alleviating the need for aircraft manufacturers to go through separate, lengthy certification programs.

“There’s a lot of work to be done” to get EASA to recognize FAA’s potential certification of the S4, Bowles concedes.

But he adds: “Below the surface of [EASA’s] decision, they’re actually reusing the same methods of compliance [previously used for other aircraft] for the most part.” This means “the technical details are not that far off, but the approach of setting these vehicles aside in Europe as special is what’s unique. We’ll keep watching as that evolves.”

And there are signs that FAA might be open to accepting other agencies’ certifications. FAA in early March issued a statement that officials were “engaged in a range of bilateral and multilateral discussions ” with counterparts at CAA “focused on facilitating certification and validating new eVTOL aircraft.”

Separately from that evolution, there is a bonus for Joby regarding the S4 being classified under Part 23: Since FAA is using existing regulations, pilots can seamlessly move from operating other types of commercial aircraft to flying eVTOLs. Those pilots will just need to undergo model-specific training, rather than starting from scratch to get licensed to operate a completely new category of aircraft. Joby aims to begin commercial operations in at least one U.S. city nearly immediately after gaining certification, so ready-made pilots are necessary.

Preparing for certification

Joby aims to complete the S4 certification by the end of next year. The company is already well into the process, having first engaged FAA in 2015 — two years before those initial flights with a full-scale prototype.

And executives are not overly concerned about the special conditions FAA will apply to the S4.

“Just because there’s a special condition, it doesn’t mean it’s something bad,” says Didier Papadopoulos, Joby’s engineer leading S4 certification. “It just recognizes the fact that existing rules don’t apply” to particular technologies on the aircraft.

“The good news about that is for the most part, all the special conditions apply to technologies we are developing in-house, so the know-how is here.”

Bowles says Joby has “baked in” extensive testing to meet special conditions into its certification timeline.

Joby sees this vertical integration of production as a differentiating strength among its competitors. Joby has been experimenting with the idea of an electrified air taxi since it was founded in 2009. When the concept was in its infancy, Joby started developing its own technologies — a practice it continues today — giving the company independence from the numerous suppliers on which most aircraft programs depend.

Joby sees two advantages to this approach: First, a disruption at a supplier will not delay the certification process. Second, and perhaps more importantly, if FAA spots a problem with a system, there will be no middleman. Joby can make the fix without depending on the engineering of another company.

“That is so critical in my mind, rather than having dependency on third-party suppliers or suboptimal designs that were really designed for broader applications and not just for this aircraft,” Papadopoulos says. “Whenever we need to make changes, it’s phenomenal how quickly we can do it.”

A big watch item for FAA, which analyst Yu says will certainly come under a special condition, is the four battery packs arrayed under the S4’s wing. He predicts that the battery packs could create weight imbalance issues that would force Joby to compromise by reducing the number of passenger seats from four to three. But Yu doesn’t think that would be a deal breaker, because Joby is targeting an average passenger load factor of 2.3.

Agreeing on process

There are three key thresholds that Joby must clear to gain type certification for the S4, one of which it crossed last year and the next it aims to complete this year, leaving 2023 to gain final type certification.

Joby last year received from FAA the “G-1 Certification Basis,” a document spelling out the agreed upon airworthiness and environmental requirements for the aircraft. FAA and Joby are now 70% through creating the follow-up “G-2” compliance checklist specifying how Joby will demonstrate through certification flights that that S4 meets those requirements. The list is scheduled to  be ready by midyear, Joby says.

Joby is in contact with FAA on “multiple fronts,” Papadopoulos says. “We have regular sync ups with them on everything from the certification [process] to the types of testing we’re going to do. We’re doing all formats of meetings, from Zoom to on-site visits by FAA.”

Once FAA signs off on the G-2, Joby can begin certification flight testing. While another version of the S4 — which Joby calls a “pre-production prototype” — clocked approximately 1,000 flights since its first flight in 2019, none of those counted toward certification. The data collected was quite valuable, but only a flight testing aircraft with the exact specifications Joby plans to bring to market can make formal certification flights.

That pre-production prototype crashed in February during a remotely piloted test flight near Monterey in California in which Joby was aggressively pushing the aircraft’s flight envelope. No one was injured, but the aircraft was “substantially damaged,” according to the report issued by the U.S. National Transportation Safety Board. A second pre-production S4 was rolled out in January and resumed flight testing in March. Joby maintains that the crash does not affect its certification timeline.

For safety, some flights of the current iteration of the S4 are conducted by remote control without a pilot aboard, such as when Joby wants to push the envelope, though that will be done cautiously. Papadopoulos says the ongoing flights with the second aircraft will not push the boundaries like the prior S4 did. The current flight tests focus “more toward lower speeds and takeoff and landing,” he explains. The next aircraft to be built, he says, will be mostly used for testing flight systems.

“We’re going to develop as many aircraft as we need” to achieve certification, he adds.

When those certification test flights commence, they will have to be piloted since that is how the aircraft will go to market. Joby has highly automated the flight controls, which company executives say will make it quite possible to transition to a remotely piloted eVTOL in the future.

Meanwhile, Joby does not have to wait for flight testing to begin the process of gaining FAA approval for smaller S4 parts and systems being refined in Joby’s design laboratory.

“You need to think about the aircraft as a sort of a pyramid with building blocks,” Papadopoulos says. “At the bottom end are the smallest components. As we move up, you’re starting to talk about larger components like a piece of equipment or a piece of electronics. And then as you move up, you’re talking about subsystems and systems and then the aircraft. It’s kind of like a series of Lego blocks leading to the final aircraft. The certification testing process requires you to go through all these layers to make sure everything bottom-up is compliant with the rules.”

In this case, a lot more than Joby’s success as an individual company could hinge on that compliance. 


Aaron Karp

About Aaron Karp

Aaron is a contributing editor to the Aviation Week Network and has covered the aviation business for 20 years. He was previously managing editor of Air Cargo World and editor-in-chief of Aviation Daily.

“It’s kind of like a series of Lego blocks leading to the final aircraft. The certification testing process requires you to go through all these layers to make sure everything bottom up is compliant with the rules.”

Didier Papadopoulos, Joby Aviation
Among the many certification tasks will be to verify that the carbon fiber composite that comprises the S4 airframe meets FAA standards for characteristics including strength. Credit: Joby Aviation
Volocopter of Germany plans to obtain European certification for its two-seat VoloCity air taxi design before seeking FAA certification to operate in the U.S. The company completed the first flight with its pre-production VoloCity in December. Credit: Volocopter

Seeking certification