The Future of Advanced Air Mobility

New Electric Aircraft Operators Face Part 135 Certification Challenges

Several of the leading players in the burgeoning advanced air mobility (AAM) field aspire not only to design and build eVTOL and eSTOL aircraft but abandon the model followed by traditional aircraft manufacturers and operate the equipment themselves. In the process, though, the AAM upstarts must assume a significant regulatory challenge and establish operating credentials under FAA Part 135 rules or equivalent legal structures in other countries.

Some have found the process so onerous that they’ve opted to effectively buy approval with the acquisition of a company with an existing certificate. Others, such as eVTOL developer Joby Aviation, have taken the direct route, filing an initial Part 135 application in June 2021 and recently announcing it had begun the fourth stage of a five-stage process.

Joby, in fact, appears to have gotten further with its effort than any of its fellow aspiring AAM providers, creating a Part 135 organization that will initially operate a Cirrus SR22 light aircraft and a “small number” of other traditional fixed-wing aircraft to allow for it to “mature passenger operations in an efficient manner.” Plans call for scaling manuals and procedures to support the eVTOL aircraft for which it expects to gain certification in 2024.

The company explained to AIN that the use of conventional aircraft will allow it to build the foundation for operations, maintenance, safety, customer handling, manuals, processes, and standard operating procedures ahead of the launch of eVTOL service. It added that the approach will also allow it to progressively improve software tools related to customer booking, pilot tools, fleet management, and multi-modal trip integration.

“We are planning well in advance to ensure we have all the pieces in place to allow for a smooth launch of our commercial eVTOL service,” said Joby head of operations and people Bonny Simi. “We are specifically doing a clean-sheet Part 135 because we think it's critically important to design the operation, procedures, and enabling technology platform together specifically for this new type of operation. Existing technology platforms simply aren't sufficient to efficiently support eVTOL operations. By building our technology platform in-house and exercising it with our Part 135 operation well in advance of eVTOL service, we can reduce complexities as we scale.” 

The company expects to receive its Part 135 certificate “later this year” and to begin operations with traditional aircraft shortly thereafter.  Asked what regulatory exemptions Joby thinks it will need to launch its Part 135 operations with the eVTOL aircraft, Simi noted that the company designed the vehicle with operational and design regulations in mind, using traditional communications, surveillance, and navigation equipment to allow for operation in today’s system and as regulations evolve.

On the reason Joby chose to apply for a new Part 135 certificate rather than, in effect, buying an existing certificate, Simi explained that starting from scratch allowed the company to customize manuals and procedures applicable to its eVTOL aircraft. “By planning well in advance, we are able to establish a clean-sheet 135 operation with the added level of robustness we want for our service right from the start,” she said. “For example, we are laying the foundation for a full safety management system [SMS], completely integrated into our operations, even though this is not FAA-required.”

In fact, National Air Transportation Association senior vice president for safety and education Keith DeBerry stressed the importance of understanding the processes associated with SMS, the design and implementation of which he said will become mandatory for Part 135 operators for the first time under a Notice of Proposed Rulemaking the FAA expects to issue in August or September. Regulations began requiring SMS for Part 121 carriers in 2018.

In an interview with FutureFlight, DeBerry outlined the procedure for gaining a Part 135 certificate, starting with a request for an application either in writing or in the form of informal meetings with district office personnel. During the so-called pre-application process, or Phase 1, the applicant needs to request access to the FAA Safety Assurance System (SAS) external portal—a free web-based application designed to allow for more direct, streamlined, and timely communication with the agency.

The FAA encourages applicants to take a free online training course that gives instructions on registering for SAS external portal user access and how to use it. The applicant then needs to submit a pre-application statement of intent (PASI) to the local Flight Standards District Office (FSDO) via the SAS portal. Once the FAA accepts the PASI, the office manager starts the certificate service oversight process, which the FAA uses to determine whether it has the resources it needs to conduct a Part 135 review. If it determines it does not, it places the applicant on a waitlist.

“The pre-application is just to kind of see if you're serious,” DeBerry explained. “Because there are a lot of people that put in a pre-application and they just drop it. It talks a little bit about your economic authority (a separate application that must go through the U.S. Department of Transportation); it talks about going through all the prerequisites to make sure that they're not really going to have any issues. But it's not a lengthy process and it's not a convoluted process and the reason for that is the formal application process becomes onerous.”

Once the FAA certification team receives all the documents required during the pre-application phase, the formal application process, or Phase 2, begins. Initial requirements involve the submission of 10 checklist items, including an application letter, company manuals, training curricula, management resumes, proof of aircraft ownership or lease holdings, and proposed operation specifications.

Next, Phase 3 involves undergoing a design assessment during which inspectors perform a review of manuals and other documents to ensure regulatory compliance and adherence to safe practices. DeBerry stressed the particular importance of SMS for applicants entering Phase 3.

“So if you were trying to get a certificate, my advice is to go ahead and develop your systems with SMS in mind,” stressed DeBerry, who further explained that SMS serves as a sort of an umbrella over the entire organization, aiding efficiency and creating a cultural mindset that stresses safety first. Proper safety practices mitigate hazards, against which a team needs to create a formal process to either eliminate the hazard or reach a point of acceptable risk. “There are really only four components to a safety management system,” he added. “It’s the safety policy, safety risk assurance, safety management, and then safety education. The safety risk management and the safety assurance aspects have interoperability, but that's the heart and soul of a safety management system.”

DeBerry also emphasized the importance of close communication between the applicant and the FAA’s certification project manager and certification project team, noting that a breakdown in communication will ultimately cause delays. “If we don’t get that right, it slows things down and it causes people to lose time and money,” he said. “At the end of the day, everyone needs to work together because if there was no Part 135 or Part 121, if there was no aviation, the FAA wouldn’t have a job. So it doesn’t behoove the FAA to be a roadblock and make things really cumbersome.”

NATA also recommends that operators access the data collection tools (DCTs) collected by the aviation safety inspector in accordance with the Comprehensive Assessment Plan and perform a self-audit. The FAA inspector uses DCTs to document assessments of the applicant’s design of systems, surveillance of certificate holder performance, identification of safety concerns or statutory/regulatory noncompliance, and any other relevant information. The DCT information helps the principal inspector, training center program manager, and certification project manager assess the applicant’s system performance and design.

“All the stuff the FAA can get the certificate holder should be able to get also,” he explained. “We look at the design of the system and then we look at the performance of the system because if we just look at the design, we can write a manual and document a process that would probably make you cry, it would be so good. But can you do what you say you’re going to do?”

Design assessments include elements dedicated to fatigue, education, awareness, training, and weight and balance control. Crucially, the FAA will require applicants to provide a compliance statement, or letter of compliance, that lays out how one would comply with each specific Part 135 requirement that applies to a particular operation.

According to some experts close to the process, securing the resulting letter of compliance can be an especially challenging stage to complete. Essentially, applicants have to incorporate all the Part 135 regulations and then list exactly how their companies will comply with each item.

“Once you get past Phase 3, which is the crux of everything, you’ve got everything documented, [answering] who’s going to get trained, how are they going to get trained, who’s going to accept responsibility for risk under safety risk management…That’s considered a Phase 3 gate,” said DeBerry. “It’s like designing an airplane; you look at everything and anything that can happen. And if it does happen, you need to ask how bad it is really going to hurt; that way you get to a risk score. Once you have that, you have a pretty solid system.”

After the FAA affirms the documented process as sound, Phase 4 starts, at which point the agency looks at the actual performance. During Phase 4, the certification team determines the effectiveness of that the applicant’s proposed procedures and programs for training and directing personnel in the performance of their duties. Essentially, the emphasis lies with compliance with regulations and the operating procedures contained in the applicant’s manuals.

DeBerry noted that Phase 4 involves proving runs to ensure a process works as intended. “So a proving run would basically be, for example, [a case when] you're piloting a triple seven and coming back from Gatwick in England to Atlanta, and so an FAA inspector could hand you a card and want you to simulate an engine shutdown in operation, and you would take all the steps except shut the engine down,” he explained. “Another case would be, as you’re getting ready to push back from the gate and the brakes locked; how are you going to handle this situation? Do you have people qualified? Do you have the proper tools? So a proving run clearly demonstrates that you have done the things that you said you would do in your document process.”

After satisfying the FAA of all Phase 4 requirements, the fifth and final phase begins and essentially involves administrative functions and documenting operations specifications, explained DeBerry. Once done with all the required paperwork, the agency issues the certificate.

In practice, though, even getting to the point at which a FSDO begins the Part 135 review process could take months or even years, if the experience of California-based autonomous flight technology pioneer Xwing serves as any guide. In an interview with FutureFlight, Xwing chief technology officer Maxime Gariel explained that the company originally sought to apply for its own Part 135 certificate but found little hope of getting past even Phase 1 within a timeframe the company considered reasonable.

“We decided to apply over two and a half years ago with the Oakland FSDO [in Alameda, California], and we got no response for a month,” said Gariel. “Eventually we found that we were number five in the pile but number one had been in the works for years. At that point, we thought we were never going to get it. So we decided to acquire our first Part 135 [San Antonio Air Charter], which was doing cargo and passenger operations.”

Gariel explained that it took about four to five months to add its Cessna 208B Grand Caravans to the then-dormant certificate, get its minimum equipment list approved, and complete all the necessary documentation as part of a process he described as “pretty quick.”

The company then began commercial flights in December 2020 as a means to learn how to manage a Part 135 operation before exploring what elements it needed to change. “One of the key things was, for instance, weight and balance,” said Gariel. “Right now, the pilot is in charge of weight and balance. What happens when the pilot is remote? Who’s taking that responsibility? So those are the things we are working on to be able to update the certificate and provide an equivalent level of safety.”

Now in the process of testing its autonomous flight system in the experimental Grand Caravan, Xwing last May filed a petition with the FAA to autonomously operate the aircraft on revenue flights from a ground-control station and under the supervision of an on-board pilot-in-command on its Part 135 certificate. As part of the petition, Xwing asked for several exemptions to fly cargo within controlled airspace.

The petition went for public comment in September and the last comment entry appeared in October, said Gariel. “We haven’t heard back officially yet but I would hope to have some good news in the near future…But we don’t have any idea right now what the position is.”

Xwing hopes to fly the autonomously piloted 208 in regular commercial service by the end of 2024. Gariel stressed that the company won’t ask for too much “right away” from the FAA, but rather accept operational limitations to the Part 135 certificate at first that would require it to fly only over sparsely populated areas, for example. “We all need to get comfortable with it,” he said. “So we’re going to make some concessions on what we can do because it’s a new type of aircraft.”

As some of the new AAM pioneers get closer to achieving type certification, some appear to have revised their planned business models. Last year, Germany’s Lilium announced a partnership with established business aviation services group Luxaviation, which will support planned commercial services using its established network of air operator certificates in multiple countries. More recently, Lilium reached an agreement with major private aircraft operator and fractional ownership group NetJets, which also plans to become an operating partner and add as many as 150 of the seven-seat Lilium Jet to its fleet.

Some eVTOL aircraft developers, including the UK’s Vertical Aerospace and Embraer subsidiary Eve Urban Air Mobility, have chosen to adhere to a traditional business model and sell their new vehicles directly to established operators. Eve has begun the process of merging with a special purpose acquisition company called Zanite, established by business aviation entrepreneur Kenn Ricci, whose interests include fractional operator Flexjet.

Ricci told a recent briefing for prospective investors in Eve, which seeks a Wall Street flotation, that he purposely chose the company because it does not intend to operate the aircraft.  “We avoided any opportunity where companies wanted to build and operate the aircraft,” he stated. “It’s a bridge too far to be both the manufacturer and the airline. You are competing with our own customers, and the capital needs are just too high.”

The second half of this decade should determine whether the mold-breaking, vertically integrated business models under pursuit by Joby and rivals including Archer and Volocopter will prove realistic. Many of the new players have told investors they will be fully operational with revenue streams in just a couple of years from now. Achieving that goal for first-time operators could see an intense compliance scramble as companies deal with type certification and preparations for manufacturing.