The targets announced in late January by California-based Joby Aviation were quite audacious: a top speed of at least 200 miles per hour (322 kilometers per hour), and an altitude of at least 10,000 feet (3,050 meters) — faster and higher than any other eVTOL in development.

Not long after, there was celebration and a lot of attention when Joby reached those goals.

On Jan. 21, its speed target was surpassed by one of its two prototypes, which that day became the fastest eVTOL on the planet. On Feb. 1, the altitude target was reached.

An industry shock came two weeks later, however. On Feb. 16, Joby reported that one of its prototypes had had an accident, piloted remotely. ADS-B Exchange data recorded groundspeeds for the prototype of up to 276 mph (444 km/h) that day.

A preliminary accident report from the National Transportation Safety Board (NTSB), the investigating body of all civil aviation accidents in the U.S., is expected in early March. The full investigation could take 12 to 18 months. Joby said it is not permitted to comment on anything to do with the accident

Timeline effects

How much this accident will affect Joby’s timeline for certification depends on the outcomes of the investigation, as they are released. Joby has stated in the past that it expects to obtain type certification from the U.S. Federal Aviation Administration in 2023, and begin commercial operations in 2024.  

“It comes down to understanding what happened in the accident,” explained Walter Desrosier, vice president of engineering and maintenance at the General Aviation Manufacturers Association (GAMA). “For any accident, we need to know if it was due to a potential design issue, an operational issue or something else. Once the contributing causes are determined, then we move on to how to address them. Does it come back to changing the design? If so, will certification requirements need to be revisited in terms of how the updated design meets requirements? These outcomes will determine how long the certification process is potentially lengthened in a scenario like this.”

As to when Joby might resume flight testing with the remaining identical prototype, Desrosier again returns to the cause or causes of the accident. That is, if it’s a design issue, then the existing prototype would need to be modified, if possible, to eliminate the issue and test flights could resume, although additional certification work may be required.

However, if the accident was due to a component that malfunctioned, an operational control factor, or an environmental condition factor, additional certification time may not be needed.

Normal process?

Desrosier noted that while the historic and current safety record for the air transportation industry is outstanding, it’s expected during testing of new designs to push the envelope with higher risk flights and to see failures or even accidents. Indeed, test failures are the norm within any industry when new products are in development.

“Test flights by definition are higher risk as they involve brand new design,” Desrosier noted. “Accidents are certainly not unheard of. And with eVTOLs, it’s a whole new type of aircraft and so there are a lot of unknowns. This isn’t a case of an updated airplane with a few design changes.”

However, in Desrosier’s view, the overall eVTOL industry product development and certification process are proceeding as they would with any new aircraft, whether it’s brand new or simply a modification of past designs.

“The process is the same, very structured and incremental with many steps involved, examining all the materials and design characteristics,” he explained. “Having said that, the certification process for eVTOLs has elements of both helicopter and airplane certification. However, the helicopter certification process is perhaps more complex than eVTOLs because it has only one mode of lift and single failure paths, where eVTOLs have multiple modes, providing additional paths to meet the safety requirements. But the certification process is the same in that each step must be followed in the same ways.”

Desrosier explained that a big part of eVTOL certification is focused on the propulsion system (a distributed electric propulsion and lift system). The next most recent major change in aircraft design before eVTOLs was also focused on propulsion, when decades ago, plane engines went from piston to turbine.

“Turbine engines and the bypass fan enabled wide-body airplanes, which enabled transcontinental flights and now we have twin-engine designs instead of four engines,” Desrosier reflected. “It was all propulsion changes that led to aircraft with new types of capabilities. It’s the same thing happening now with eVTOL.”

As to whether being the first to the finish line of eVTOL certification is pushing product timeline goals, Desrosier doesn’t believe so. “There are always companies developing new products and their timelines are always ‘stretch’ goals, meaning that they’re flexible. It’s an iterative process and companies have to adapt,” he said. “I think the timelines I’ve seen from Joby and others are consistent with other past product development timelines.” Before the accident, on Feb. 11, Joby had began conformity testing for FAA credit, another step toward type certification.

Neither does Desrosier believe this accident, or other accidents during various company test phases before certification, will impact much on public perception of eVTOLs going forward.

“The development of a new type of aircraft is only one part of introducing it,” he said. “There is policy infrastructure to be developed, infrastructure to provide charging, and much communication with the public ahead. There is an awful lot more to be done to have eVTOLs be a reality beyond certification of the vehicles themselves. Public perception is a very important part of introducing a new mode of transport, but I don’t think this accident will impact it. What we have to remember is that the air transport industry has an outstanding safety record, better than any other mode of transportation. I think we should all have confidence that integrating eVTOL transportation will not change that.”