Printed headline: The Future of UAM
This year’s Consumer Electronics Show (CES) show in Las Vegas took up nearly 3 million ft.2 of exhibition space, but a new prototype built to fit within a 37 X 37-ft. helicopter landing site was one of the biggest, most eye-catching technology debuts on the scene. Crowds gathered to watch as Bell’s Nexus electric vertical-takeoff-and-landing (eVTOL) concept demonstrated the 90-deg. tilt motion of its six ducted fans, powered by a hybrid-electric propulsion system incorporating batteries from EP Systems and a turbine engine from Safran.
Bell, which is teamed with Uber to develop a flying taxi model to begin commercial operations by the mid-2020s, sees eVTOL air taxis as the way to alleviate roadway congestion, reducing both travel time and costs. Although the Nexus is built to carry four passengers and a pilot, the eventual goal is to replace the pilot with an autonomous system.
If the crowd’s excitement over the Nexus was any indicator, the public is clamoring for the possibility of making flying taxis a reality. However, a recent global survey by Deloitte found that although nearly half of respondents viewed autonomous aerial passenger vehicles as a potentially viable way to alleviate roadway congestion, 80% are concerned about safety. Deloitte reports that in addition to safety concerns and psychological acceptance, a host of other barriers—ranging from air traffic management (ATM) to infrastructure issues—still stand in the way.
“The less that people understand something, the more there’s the opportunity for fear or misunderstanding,” says David Rottblatt, business development director for EmbraerX, which is working to build its own eVTOL concept and aims to begin flight demonstrations by the end of 2021.
Rottblatt says disruptive innovations like the eVTOL and urban air mobility (UAM) industries can succeed where others have failed by educating stakeholders on how new technology can create value. “I think that education and partnership with community leaders and residents of that community will be the make-or-break element of making sure that this is something that can be accepted globally,” he says.
Perhaps one of the biggest challenges to acceptance is the concept of autonomous rather than piloted flying taxis. According to Robin Lineberger, global aerospace and defense leader at Deloitte, piloted versions could help to convince the public that flying vehicles are safe, since they will be much more similar to flying in a helicopter.
“There are fewer barriers to get into that because you don’t have the psychological barrier of getting into an unmanned vehicle,” explains Lineberger. “All of the technologies, at least individually, are fairly proven. There’s a placebo effect of having someone in the pilot’s seat. I think it’s a much bigger leap for the autonomous [vehicles], in that if there are accidents along the way, whether manned or unmanned, they’re more likely to impede adoption in an unmanned environment, than in a manned environment because we still get on airplanes and helicopters, and we still fly civil aviation airplanes.”
Lineberger believes algorithms developed through machine learning to determine how pilots react in different situations—such as various wind speeds or altitudes, diagnosing bad landings and dealing with air traffic—will play a major part in establishing an impeccable safety record in the early introduction of autonomous flight. To help reassure consumers of the safety of autonomous aerial passenger vehicles, Deloitte also recommends that OEMs equip them with emergency landing systems and enhanced safety equipment, such as “detect-and-avoid” sensors.
Scott Drennan, Bell’s vice president of innovation, says the Nexus’ fly-by-wire system is the first step to a truly autonomous vehicle. “[The system] starts to take away those dumb, dirty, dangerous and dull tasks and makes the pilot into a system, safety and mission officer rather than—as we strived before—the person trying to keep every bit of information aligned in a very difficult flight situation or control situation,” says Drennan. “It starts with someone in the cockpit with it and then extends from optionally piloted vehicles to remotely piloted vehicles, all the way to fully autonomous.”
Another major challenge the industry needs to overcome is ATM and the regulatory environment. With increased traffic in the air, concern abounds over how air traffic controllers will be able to manage it without becoming overwhelmed. “The idea of the old control tower is dead,” states Lineberger, adding that the ATM model will need to be flipped from its traditional method. “This is going to have to be driven by computers and assisted by people,” he asserts.
Lineberger points to the idea of a third-party model, in which the FAA delegates management authority to different companies positioning themselves as candidates for providing ATM services. The concept is currently being explored in two NASA projects, Air Traffic Management-eXploration and the Urban Air Mobility Grand Challenge. However, EmbraerX’s Rottblatt emphasizes that third-party delegation of this authority will be a country-by-country and city-by-city decision.
Rottblatt says EmbraerX and other stakeholders in the UAM industry are working with air navigation service providers to determine what kind of ATM infrastructure and procedures need to be in place for the industry to ensure safety. A major concern for EmbraerX is ensuring that procedures are in place so the number of flights allowed to take off and fly in a given city are not capped. An example of this, says Rottblatt, is Sao Paulo, where the Brazilian Air Force—which serves as the country’s air traffic authority—limits the number of helicopter flights to preserve the arrival corridor into Sao Paulo-Congonhas Airport.
“Today, there’s so much more demand than supply because we have this artificial cap on how many helicopter flights can exist in Sao Paulo at any one time,” says Rottblatt. “We want to avoid this artificial cap from existing in other cities, so that when the eVTOL industry launches, it will grow organically, and there will be existing infrastructure in place to allow for it to happen safely.”
Rottblatt says this could entail the creation of more VFR (visual flight rules) corridors or the creation of an eVTOL-dedicated layer of airspace, where only specifically equipped aircraft that meet a minimum standard for equipment and performance capabilities are allowed.
One concern for eVTOL flying in low-altitude environments is frequency congestion and automatic dependent surveillance-broadcast (ADS-B). Rottblatt explains that although ADS-B is a great resource, “spoofing” occurs, where frequency congestion prevents an accurate read of what is happening in an aircraft’s immediate vicinity.
“I think one of the things we need is either a new frequency for ADS-B or a different type of cooperative surveillance technology that allows for UAM to grow organically without any kind of procedural limitation for how many flights can exist at any one time,” explains Rottblatt. “We’re exploring with communication, navigation and surveillance partners what those options could be.” He says this could entail staying with ADS-B, using similar technology on a new frequency or creating something entirely new.
“What’s very important is that it be a safe and secure information-sharing mechanism,” he continues. “In the age of [the Internet of Things] and cyberattacks, we want to make sure that whatever we use is a protected medium for sending and receiving information, especially as the vehicle continues to evolve in its intelligence so that more decisions are ultimately made autonomously onboard the aircraft, and there’s less manual input from the pilot.”
Easier Maintenance Model
When it comes to more air traffic above urban areas, another concern the public has expressed is about noise levels. According to Drennan, this is an area where eVTOL vehicles like the Nexus provide significant advantages over helicopters.
“We have six 8-ft.-dia. ducted fans, and those smaller diameters allow us to operate at lower tip speeds. On top of that, the ducts attenuate and directionalize the acoustic signature,” he explains. This has reduced decibel levels and changed the tonality and frequency of the vehicle’s sound. “It often reminds me of urban ambient noise, so we’re really looking forward to blending into those urban communities,” Drennan adds.
Differences between eVTOL vehicles and helicopters should also provide benefits in terms of maintenance. Drennan says a traditional helicopter’s three basic maintenance items are a complex rotor system, transmission system and engine, which require the aircraft to be on the ground for maintenance to be performed.
“When you have a more electrified system, whether hybrid or fully electric, you start to get into maintenance that occurs off the aircraft because you have line replaceable units in the form of electric motors,” explains Drennan. “I’d much rather send the electric motor back to Safran to deal with at their factory than to have a maintainer on board, especially when it means keeping the aircraft on the ground.”
In addition to having fewer moving parts that need to be maintained, the battery technology in eVTOL vehicles shows promise for increasing intervals between maintenance. “The maturation of battery technology and the consolidation of energy in batteries today will allow for a greater duration of the battery before we either need to recycle it or take it out of operation,” says Rottblatt. “That will translate into certainly more cost savings for the passenger, because we won’t need to have as much jet fuel purchasing and as a result fewer moving parts or fewer internal combustion parts that require more servicing. I think that will definitely translate into how our business model is designed for maintaining the aircraft.”
Rottblatt says this model will entail charging points at vertiport sites where the aircraft land and undergo inspection to ensure airworthiness. “If an aircraft takes off at 100% charge and lands with 80% charge, for example, we’ll recharge it using a very fast charging mechanism and get it back up to, say, 90% charge,” he explains. “So we may get six or seven flights out of the aircraft before we need to take the batteries out and equip with fresh ones, and then those batteries will spend the next half-day being recharged back to 100%.”
While a common vision for air taxis involves vertiports on top of tall buildings in urban centers, Lineberger believes this could be a boon for maintenance, at least initially. “Those buildings will need to be at least small or interim service centers,” he says. Although Lineberger thinks this model is what air taxis will use at first, “ultimately, I don’t think they’re going to go land on one of those unless they’re prepared to take all the maintenance crews up there every time,” he says. “It’s got to have a small depot around it when you land it. You can’t land it 33 stories up, because if it gets broken, what are you going to do? It’s a challenge.”
One proposed model Lineberger sees as becoming realistic is using parking garages, such as those at airports or in urban centers, as combination landing sites and maintenance centers. Lineberger says if UAM really takes off and there are fewer cars on the road, the need for fewer parking spaces means garages could be redeveloped into landing and takeoff platforms where maintenance and logistics facilities are incorporated into the lower levels.
So where, realistically, will UAM take off, and how many companies can survive long-term?
Rottblatt says the UAM industry already exists in the form of on-demand helicopter booking platforms such as Voom and Blade in cities like Sao Paulo and Mumbai, but the industry outlook points to limited commercial operations of eVTOL in test cities such as Dallas and Los Angeles by 2023. He believes there will be an exponential rate of adoption over the following five years and that UAM will be a household-recognized available resource by 2028.
“I think one of the first use cases that will resonate most with the public is going from the airport to downtown, or intra-city operations,” says Rottblatt. “Those are short hops that can take several hours to accomplish otherwise. As the model evolves, Embraer envisions a future where UAM will certainly be brought closer to home, such that you’ll be able to have a vertiport that is within your community, and you will no longer need a personal vehicle. Your way of getting around will be to simply subscribe to your own rideshare service that will take you wherever you want to go, and you’ll either have X amount of credits or you’ll pay per use.”
In terms of the most promising locations for UAM, Rottblatt sees the most growth potential in areas with the greatest traffic congestion. “It’s a simple product of populations continuing to grow and urban sprawl that can’t expand anymore,” he says. “[It will also take off in] countries that have grown to be shared-economy- and rideshare-friendly.”
Lineberger predicts that UAM will first be introduced in areas where the government has centralized authority to control regulations. He points to Saudi Arabia, which is already piloting the concept between Dubai and Abu Dhabi with German startup Volocopter.
The arena is crowded with established OEMs and startups alike vying to create air taxis. Boeing subsidiary Aurora Flight Sciences recently completed the first test flight of its all-electric autonomous passenger air vehicle. Terrafugia, which is putting its Transition flying car on the market this year, is working on a four-passenger eVTOL concept called the TF-2, targeted for certification in 2023. AeroMobil is seeking type certification for its AeroMobil 4.0 flying vehicle, and Lillium is developing a five-seat eVTOL. Airbus is starting unmanned flight trials of its CityAirbus flying taxi prototype this year. But which company (or companies) will come out on top?
Lineberger thinks industry leaders will come from OEMs with both commercial and defense businesses but startups with expertise in developing advanced technologies such as autonomy and composites, or automotive companies—which have plenty of experience with autonomous sensors and models for building and servicing mass-production fleets—could give them a run for their money.
“It becomes a choice of where in the value chain that individual organization wants to operate,” he says, pointing to the regional-jet model, where flights booked under a larger carrier are operated by a smaller regional carrier. Lineberger says the Uber operating model to which companies such as Bell and EmbraerX are looking will be similar, where Uber serves as the booking platform while other companies manufacture, operate and maintain the vehicles.
Rottblatt notes that the market is very fragmented between large OEMs and more than 60 startups. “There will be consolidation and eventually market leaders,” he says. “I think that process of recognizing who has both the business model and the ability to certify a safe aircraft will be a litmus test for a lot of startups as well as established companies, to make sure that they build a safe aircraft the public can trust. Given how difficult it is to certify and test, it will be a very successful and efficient way to thin out what is today a very large population of potential manufacturers.”