Is the Future of Aerial Autonomy up in the Air?
At January’s CES ’19, more than 170 exhibitors showed aerial drones of various shapes and sizes. Potential use cases for these devices appear to be limitless, but technical, legal and regulatory hurdles must first be overcome.
Drones are categorized by vehicle weight. The small devices weighing between 0.55 and 55 pounds (.25 kg to 25 kg) are known as Unmanned Aircraft Systems (UAS) and are lightly regulated. Drones exceeding 55 lb are regulated as traditional aircraft. Operators must obtain proper registration, licenses and certification for airworthiness.
Drones have a foothold in today’s aerial-vehicle marketplace—but air taxis are not far behind. One of the most impressive CES displays was the Bell Nexus, an air taxi concept that is claimed to be capable of carrying five passengers up to 150 miles, at speeds up to 150 mph (241 km/h). Initially designed to have a human pilot, the Nexus is an eVTOL—hybrid-electric vertical take-off and landing craft. It employs a single gas turbine to generate electricity for six tilting ducted fans and their batteries.
Bell is aiming for $0.50-per-mile operating costs for Nexus. It is partnering with Uber to create a network of city-based flying taxis as a ride sharing service. At least 19 companies are developing similar products. Many are approaching the “on-demand aviation” market with eVTOL or conventional VTOL solutions to minimize problems in crowded cities. However, making VTOL a reality will require additional infrastructure and air-traffic control. Some facility options include vertiports (hubs with the ability to take off, land and charge) and vertistops (a single landing pad) that require only discrete locations rather than converting an entire roadway or traffic system.
Legal challenges for aerial autonomy
Significant time is being dedicated to mitigating the legal risks of drone delivery services. As these devices are typically sized according to their design payload, heightened regulation is expected for the drones themselves and their operators.
Privacy rights have also entered the discussion. One relates to surveillance; drones may capture images as they deliver their packages. There are also the myriad risks of drones trespassing on private property, colliding with other aircraft, or with ground vehicles and people, and otherwise causing damage and public nuisance. As the world saw recently with illegal drone activity at major U.K. airports, it is likely that more such issues will make headlines as companies begin to employ this technology in new ways.
Air taxis, by comparison, would live under the current regulatory schemes set by the U.S. Federal Aviation Administration (FAA) and European Aviation Safety Agency (EASA) and a few others. Autonomous VTOL systems will face their first challenge when regulators agree to the set of rules that apply to general aviation aircraft. They will need to be certified under Federal Aviation Regulation Part 21.17(b)—the FAA’s type certification for very light aircraft—to demonstrate an “equivalent level of safety” as proven in an experimental program.
This certification, unlike the self-certifying regime used by the ground vehicle industry, confirms that an aircraft is manufactured to an approved design and complies with airworthiness requirements. After accepting or addressing any missing standards, the airplane definition and detail definition phase begin. Then the craft is built and tested. Upon completion, it moves to certification.
This process can cost millions and require significant time to achieve. Boeing’s eVTOL made its first autonomous test flight in January 2019, hovering for under a minute. Airbus followed suit the same month. Experts predict that production-ready VTOL craft will be available as early as 2020, but development is still in the early stages and certification challenges loom.
Proponents like Uber believe that the design of any VTOL must be safer than driving a car when considering a fatality-per-passenger-mile (FPPM) basis. Indeed, Uber suggests that the target should be one quarter of that found under the current regulations. Under FAR Part 135, statistics show that operations of small commuter flights tend to have twice the fatality rate of privately-owned ground passenger vehicles. Uber advocates that VTOL air taxis should cut this number to half the ground vehicles’ FPPM.
To achieve this and to mitigate safety risks, systems must be designed for optimum redundancy and robustness. Take-off and landing and flight controls will need to address hazardous states and edge cases, with focus on the heightened risk in aerial vehicles.
It will be many years before an autonomous air taxi system enters commercial operation. In Uber’s October 27, 2016 white paper titled “Fast-Forwarding to a Future of On-Demand Urban Air Transportation,” the company acknowledges the “serious potential” but also the need to move stakeholders to address the “political, policy, infrastructural, and socio-economic issues” that surround autonomous VTOL flight.
Recent developments such as those unveiled at CES clearly show that stakeholders are mobilizing. Autonomous air transport is in our future.