eVTOLs and Flying Cars Not Quite Cleared for Takeoff
But an UAM Traffic Management (UTM) System Is Taking Shape
“Ground control to Major Tom. Ground control to Major Tom.” (David Bowie flashback.)
According to its latest reporting, the U.S. Federal Aviation Administration (FAA) is managing roughly 16.1 million flights annually, averaging about 44,000 flights daily. That’s about 5,400 flights at any given moment.
The advent of urban air mobility (AKA advanced air mobility) is expected to add some 430,000 air taxis/eVTOLs to the airspace, according to consultancy and analysts, Frost & Sullivan.
The skies may be “friendly” (per United Airlines), but they are also going to get a lot more crowded. Air traffic management (ATM), or more specifically, UTM (urban air mobility traffic management) is going to get a lot more complex and challenging. How’s that gonna work?
Actually, it seems like it’s gonna work pretty well.
A Phased Approach to Flying Cars
Flying cars—eVTOls or hybrid VTOLs, if you will—will soon be here. But it’s not like on Day One there will be half a million or so new air vehicles overhead. So, the National Aeronautics and Space Administration (NASA) is taking a phased approach to the integration of these vehicles into our airspace: Emergent UAM Operations, Early Expanded UAM Operations, and Mature UAM Operations.
In the Emergent phase, NASA expects “low-tempo, low-density” flights traversing a limited set of predetermined routes along several takeoff and landing zones.
During the Early Expanded phase, the Agency anticipates “higher-tempo, higher-density” flights where vertiports feed hubs and UAM operators and third-parties manage the traffic flow.
The Mature phase, NASA believes, will see “high-tempo, high-density” flights in substantially greater quantities and in a larger geographic area than the national air space (NAS) currently supports.
At first, UAM ops will be “for demonstration purposes” only. They will use existing visual flight rules (VFR), be piloted, and air traffic controllers will dictate flight ops much as they do now. But, that’s not necessarily the endgame NASA, the FAA, or operators foresee.
Scalable, Flexible, Safe
The goals for integrating UAM call for the addition of minimal air traffic control (ATC) infrastructure (radar systems, controllers, etc.) and minimal changes to FAA automation systems. They also want to increase controllers’ workloads as little as possible; ditto for existing airspace users.
Vehicle-level safety and system-level safety remain paramount without single points of failure or common failure triggers. The UTM system should be resilient to disruption—weather, software, GPS failures, and more. This system should be economically scalable and allow for user flexibility and decision-making as much as possible.
Several hurdles must be overcome for UAM and its UTM system to be successful. These include ease of certification, auditory noise, visual noise, ride quality, emissions, operating costs, protection of life and property in the air and on the ground, and energy efficiency.
This means UAM vehicles and systems need to be interoperable with each other and current airspace users. A data exchange architecture for communication, navigation, and surveillance (CNS) will be critical. UAM is expected to provide substantial economic benefits to the communities they serve and the nation as a whole, making it critical to facilitate these emerging technologies.
As with conventional air travel, security issues will be a concern crucial for UAM success. Passenger screening, cybersecurity of system controls, and the safe, reliable transmission of data—from vehicle data to weather data—will need to be (and are being) addressed.
Since, by definition, UAM will largely operate in densely populated metropolitan areas, safe airspace operations are also key to acceptance of this new mode of transportation. With NIMBY (“not in my backyard”) a common refrain around air transportation hubs, sensitivity to local residents’ concerns must also be addressed.
The Good News about UAM
“Time is money” the saying goes. UAM is expected to shave time off people’s travel needs. The expansion of air travel options will undoubtedly lead to less congestion on highways and byways. And, with the likely increase in electrically powered ground transportation, the expansion of the electric power grid they require means less additional infrastructure will need to be added to support UAM; the applications of the power support will simply be expanded and enhanced.
Vertiports, while not pop-ups, are less expensive to fabricate than airports because they might use existing structures and therefore take up a smaller footprint in the landscape.
The communications networks that support current national airspace system (NAS) operations can be modified to support UAM. Voice communications, navigation services, and surveillance systems can tie into radar, infrared tracking, and advanced detect-and-avoid (DAA) technologies.
Scope It Out
The burgeoning UAM community-at-large is targeting a wide scope of operations, everything from air taxi services to air cargo, medevac, news gathering, search and rescue, weather forecasting, law enforcement, and military applications. This necessarily means there could be a variety of vehicle types that extend beyond conventional “tube and wing” designs. UTM will need to take this into consideration to provide effective management of the airspace.
By definition, UAM operations will be within metro areas. Operating within Class B airspace (around major airports), Class C airspace (around mid-size airports), or Class D airspace (around smaller airports) will require eVTOLs/hybrid VTOLs to communicate with air traffic control while in these zones.
Risk assessment is always being evaluated by regulators; risks of unplanned events occurring, exposure during the unplanned event, and the impact and consequence of such events.
The Groundwork Necessary for Takeoff
Agencies, such as NASA and the FAA, have safety as their foremost concern (thankfully). The integration of UAM necessitates research into congestion management, vertiport network scheduling, and tactical planning, such as route separation.
Delays, especially while airborne, require manufacturers and regulators alike to balance vehicle energy management when something unplanned occurs. Research could help define the routes and schedules to accommodate arrivals and departures at vertiports. Service disruptions, while never expected, must be anticipated if UAM are to reliably and safely operate. Hazards, risks, system failures, cybersecurity issues, all must be considered. All potential hazards must be taken into account before the first UAM aircraft take flight.
To achieve this, NASA’s work might incorporate fast-time simulations, human-in-the-loop evaluations, and live flight demonstrations. Other accommodations might include augmented visual flight rules, dynamic delegated flight corridors for UAM aircraft, automated decision-support services, and performance-based operations (where some manufacturers’ VTOLs are given preferential treatment based on how well their aircraft meet predetermined performance criteria).
With 300 enterprises now vying to design, develop, and manufacture the eVTOLs and hybrid VTOLs many have envisioned for decades, UAM is a certainty. Cities, states, and federal governments the world over have taken notice. They are doing what governments are too often not given credit for—planning ahead.
An integrated, sophisticated, capable air traffic control system is as much in the works as the vehicles themselves. To quote actor Al Pacino’s character, U.S. Army Lieutenant Colonel Frank Slade, in Scent of a Woman: “Hoo-ah!”
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