Air Taxis Are Coming: The Planning Starts NowApril 2021
Topics: Air Traffic Management, Transportation, Aircraft, Airspace, Aviation Administration, Modeling and Simulation, Operations Analysis, Strategic Planning
Need to get across your city fast? What if you could just whiz above the traffic instead of competing with it on the ground?
The technology to enable routine aerial mobility is rapidly advancing. Air taxis could be a reality sooner than you think. Dozens of aircraft manufacturers are already developing these urban air mobility (UAM) vehicles. They’ll fulfill a variety of missions, from rapid transit across town to the delivery of urgently needed cargo.
Early UAM vehicles will have a pilot on board to ensure safety, but they’ll be largely automated aircraft. Industry’s ultimate vision is to operate them without an onboard pilot.
While development of these unique aircraft is well underway, today’s flight rules won’t accommodate a growth in operations. MITRE—operator of the Federal Aviation Administration’s (FAA) federally funded research and development center—is working with the FAA and the aviation industry to address that gap.
A first step has been to explore short- and long-term approaches for integrating UAM vehicles into the National Airspace System (NAS). Since UAM vehicles will fly in the domain of air traffic control, they need to be managed in a way that ensures safety and minimal disruption to existing airspace operations.
“We believe initial low-volume UAM operations with a pilot on board could be managed much as helicopter traffic is managed today,” says Brock Lascara, who leads MITRE’s UAM research efforts. However, another set of rules will be needed for the higher-volume and more automated operations that will follow.
“For that phase, our research supports the creation of UAM-specific routes and corridors,” he says. These corridors will help to standardize and simplify interactions with existing airspace users and air traffic control.
Fulfilling the Promise with Advanced Automation and Information Exchange
In this envisioned future, each region would develop its own procedures based on the desired operations and the region’s unique aspects, such as terrain, vehicle mix, and airport locations.
“However, although UAM corridors may accommodate demand in the short term, they’ll limit where operators can fly,” Lascara explains. So, in the longer term, with a change to rules and procedures and performance-based flight technologies, UAM operations are possible outside designated corridors.
In that scenario, all vehicles—both manned and unmanned—would need to share real-time flight information with other aircraft and with the various entities on the ground responsible for managing air traffic of all kinds.
“We’re investigating the technology that would support that kind of cooperation and scalability, while also allowing the NAS to be resilient in a variety of scenarios, from rocket launches to unexpected weather events,” says Jason Giovannelli, who heads MITRE’s research on using such technology in the UAM environment.
Examining Unique Urban Weather Hazards
While these phases offer a broad roadmap to UAM integration, there are myriad safety and operational issues within each phase to resolve. At MITRE, we’re making inroads on those issues as well.
For example, we’re working to determine when buildings, tunnels, bridges, and other structures would create channeled winds and turbulent eddies that could be hazardous to UAM vehicles.
MITRE, along with atmospheric science and engineering firm Aeris, is researching this question using the Joint Outdoor-indoor Urban Large Eddy Simulation (JOULES) model. JOULES simulates urban microscale wind and turbulence conditions with a high degree of resolution.
We’re using the JOULES model to evaluate the Atlantic City environment. Wind conditions there can vary by time of day and time of year. They’re also affected by large buildings along the city’s boardwalk.
“We’ll use findings from this work, coupled with UAM aircraft information, to develop algorithms that convert weather data into mission-specific aircraft hazards,” says Mike Robinson, who heads this effort.
Forecasting the UAM Future
More broadly, we’re developing a model for forecasting how many UAM flights are likely to occur in the coming years, and where. That work supports the FAA’s planning for these novel operations.
An array of factors will influence those numbers, and MITRE is exploring them all. We’re starting with two use cases, based on UAM vehicle operators’ plans: an intercity use case in Los Angeles and a between-city scenario in Florida, centered around the Orlando metropolitan area.
“The operators have already provided some statistics about how far their vehicles are expected to travel and the price range they plan to charge,” says Simon Tsao, who leads the forecasting project. “But there’s much more to consider.
“We’re comparing how long it would take other modes to make the same trip and at what cost, including time costs” he says. “That’ll allow us to forecast the market share UAM operations might capture.”
Tsao and his team are examining barriers to growth as well, including community noise concerns, airspace restrictions due to nearby manned air traffic, or infrastructure requirements—such as the need to build vertiports where UAM vehicles can take off and land.
The researchers are also incorporating socioeconomic data from the Census Bureau and the Department of Labor into their projections. “Population density, income levels, and destination types will all play a role in the demand for UAM transportation and how successful it will be,” Tsao explains.
“Because this data is so diverse, we’re not just talking about creating a few lines of code,” he says. “We have to create an analysis methodology to make sense of it all. That’s the true challenge."
Fortunately, MITRE has extensive forecasting experience, both with manned air traffic and with unmanned aircraft systems. “That’s one of the reasons the FAA relies on us for this work,” Tsao says. “It’s that connection between our expertise in the manned and unmanned arenas, combined with our deep analytical capabilities.”
Ultimately, MITRE’s UAM demand analysis and traffic-level forecasting will inform FAA regulatory action.
“Our work complements work Brock’s team is doing in the regulatory arena,” Tsao notes. “By performing analyses to better predict the future of UAM traffic, the FAA can better implement the rules and regulations to govern that traffic—and keep all airspace users safe.”
—by Marlis McCollum