The Future of Flight Will Be Built on SAFETY

Any doubts about the speed in which next-gen technology is changing aviation were swiftly removed last year on the battlefields of the South Caucus.

From September 27 to November 10, the militaries of Azerbaijan and Armenia fought a war over the disputed Nagorno-Karabakh. Though numerically similar in manpower, the outcome was a rout; years of investing oil revenue into its military budget gave the Azerbaijani forces a decisive technological advantage.

The key weapon systems leading to the victory were unmanned aircraft. Used for reconnaissance, precision strikes, and propaganda, Azerbaijan’s Bayraktar TB2 drones cut through Armenian armored vehicles and facilitated lethally precise artillery strikes. The short but bloody conflict sent a clear message to the world: tomorrow’s aerial battlefield is already here.

The future of aviation was on display in those mountain valleys, but the full realization of its commercial potential is still years away. It is one thing to show performance capability for military objectives, another entirely to prove that technologies poised to shape aviation’s future – including unmanned aircraft systems (UAS) and Electric Vertical Take-off and Landing (eVTOL) aircraft, which hover, take off, and land vertically — can safely integrate into the National Airspace System (NAS).

“Military use of unmanned aircraft is showing this technology’s utility but it’s a very different regulatory picture than commercial use,” said Tom Furey, CEO of Sagetech Avionics, which develops situational awareness avionics for unmanned aircraft. “There is substantial economic benefit for the commercial use of UAS — long-range pipeline inspections, bridge inspections, deliveries – but operators are limited by the need to interoperate safely in civil air space.”

The reality for unlocking the full capabilities of unmanned and electric aircraft — including long-term industry goals like Advanced Air Mobility (AAM), manned or automated air taxis that will zip passengers and cargo around cityscapes – is that regulators must be convinced these technologies will not disrupt a century’s worth of hard-earned safety infrastructure.

Considerable research, testing, and standard setting must still occur before next steps like widespread Beyond Visual Line of Sight (BVLOS) UAS operations receive the regulatory green light to become commercially scalable.

But every day, technological breakthroughs are pushing the industry closer to its long-term strategic goals. From increasingly sophisticated Detect and Avoid (DAA) systems that ensure unmanned aircraft recognize and act on collision threats, to remote pilot training built on long-established best practices, the future aviation sector is maturing rapidly – and answering many of the safety questions asked of it.

What’s The Frequency, Kenneth?

An example of the work that goes into answering these questions took place on June 14 in Bigfork, Montana, when uAvionix, which provides safety solutions for the integration of UAS into the NAS, conducted a 40-mile Beyond Radio Line of Sight demonstration of its internal test eVTOL UAS.

This demonstration showcased multiple technologies integral to unmanned flight: the company’s George autopilot flight control solution, which leverages DO-160G and DO-254 design assurance to enable autonomous flight; SkyLine Command & Control (C2) infrastructure management service, which manages communication with the aircraft; skyStation Ground Radio Systems (GRS), which expand the data link coverage range; TSO certified truFYX SBAS GPS, which provides a certified position source for UAS navigation; and pingRX Pro ADS-B IN DAA receiver

One of the myriad challenges facing unmanned entry into civil airspace was quickly apparent.

“We were mounted on a transmission tower that included high-power UHF broadcasts, and one of the two redundant radios experienced interference from that system,” said uAvionix president Christian Ramsey. “But the secondary radio was not affected; although they are designed to operate from the same frequencies, in the same enclosures, they have different antennas and filtering architectures to make them more robust against interference.”

With the interference mitigated through the company’s frequency hopping algorithms, the flight was uneventful — exactly the kind of demonstration that will need to be repeated consistently over the coming years for unmanned technology over 55 pounds (the current limit of Federal Air Regulation Part 107, which provides guidance and pilot certification for use of <55 lb. small UAS) to take the leap into widespread commercial viability. The industry is moving towards legally enforced protected spectrum frequencies, which regulators will control certification access to through Technical Standard Order (TSO) certification. To prepare for this, Ramsey says his team is focusing on the “enterprise service layer” for C2. “You’ve got radios dotting your landscape and each of those radios in isolation has the credential of a TSO, but that’s not all there is to it,” said Ramsey. “You have to figure out how to tie those radios together with the underlying network and architecture — cyber security, redundancy, and everything that will manage that system.”

Detecting and Avoiding Airborne Hazards

Manned aviation has long utilized commercial versions of an Airborne Collision Avoidance System (ACAS) to make interrogations of Mode C and Mode S transponders of nearby aircraft. Three versions of ACAS are in development for UAS: ACAS-Xu (fixed-wing UAS operating under Part 91 or Part 135 rules), ACAS-Xr (Xu for rotorcraft), and ACAS-sXu (sUAS).

Sagetech develops ACAS-based DAA solutions that aim to help push unmanned and EVTOL manufacturers through the ever-evolving compliance process using miniature components specially made for the unmanned market, like its MXS Mode S Transponder and MXE Mode S Interrogator.

“The ultimate goal is connecting proven robust and reliable collision avoidance technology directly to the autopilot so if you send your asset to inspect 300 miles of pipeline and it encounters another aircraft, it will automatically avoid it without someone having to watch every step of the way,” said Furey.

On July 27, Sagetech performed two types of flight trials of its DAA systems — manned, using Piper Archers, and unmanned using a Penguin C UAS — and demonstrated that its system always recognized the other aircraft and provided the appropriate alerts and warnings.

“This was cooperative collision avoidance; our next step will be to integrate radar — non-cooperative sensors,” said Furey. “It will go into the same logic, it just won’t coordinate with the other aircraft. It will recognize traffic, classify it as a possible collision and react without communicating with the other aircraft.”

Avionics for Complex Missions

One key advantage of unmanned over manned aircraft is their ability to fly over hazardous areas where the operation of unmanned aircraft could be risky for the crew.

Industrial use of unmanned aircraft will require reliable functionality in difficult weather conditions, such as those found in marine environments. Madrid-based UAV Navigation, which develops autopilots and flight control systems for unmanned systems, specializes in this area.

One of the most difficult challenges for VTOL platforms is the transition from vertical to horizontal flight and vice versa; the UAV Navigation flight control system automates this critical procedure while providing operators with safety procedures and logical redundancy to ensure the aircraft reaches a safe landing zone in even the most challenging environments, such as those without a reliable GNSS signal.

“If you plan to go to a moving vessel or frigate, for example, you need to take into account factors such as wind turbulence and the electromagnetic environment,” said Miguel Ángel de Frutos, CTO of UAV Navigation. “It is a big piece of iron in the middle of the ocean; if you plan to use an altimeter, the interference could make it tricky.”

The company’s extensive research into causes of component failure, including the need to defend against jamming attacks, has borne fruit in products like its VECTOR-600 autopilot for fixed wing, rotary wing, and VTOL UAVs, which is designed to survive all individual sensor failures.

“We take pride in our approach to redundancy because it’s not about having just one landing — it’s about having 10 successful landings in a row,” said Ángel de Frutos.

Revolutions in Autonomous Flight

Minimizing human involvement in the flying process will be the greatest enhancement to aviation safety, argues Luuk van Dijk, founder, CEO and CTO of Switzerland-based Daedalean, which develops autonomous piloting systems.

Humans are not only a performance bottleneck to denser use of airspace, according to van Dijk, but will increasingly be a problematic factor for companies looking to make the AAM space profitable. Pilots take up space on the already small EVTOL aircraft, necessitate limited flight schedules, and pose labor supply risks (e.g., the projected pilot shortage).

To make the case that Daedalean’s systems based on Machine Learning can replicate and exceed human capabilities – in other words, the ability to solve problems currently only solved by human pilots and air traffic controllers — they chose to replicate piloting under Visual Flight Rules (VFR) as natural starting point.

“We concluded that in VFR, the visual information is much richer and much more reliable than what the existing instruments bring. To truly match that level of precision reliability and availability, you will have to make something that is as aware of its surroundings as the human pilots,” said van Dijk.

Daedalean’s Machine Learning-based visual systems are aimed at working on VTOL/rotorcraft and fixed-wing aircraft. They consist of several (one to four) avionics-grade cameras and a computing platform running the company’s algorithms; the sensory input is fed into this in real time to provide situational data for visual positioning (which allows navigation alternative to GPS), traffic detection (visual DAA, including non-cooperative hazards) and visual landing — all the tasks performed by a pilot under VFR.

“We figured if you want to build autonomy to fit in the airspace as it is today, you have to make a pilot, or first a co-pilot, that can satisfy all those rules,” said van Dijk. “Reducing cockpit workload is really the proving ground for the technology. We have to show that we can reach a safety level that in turn allows an increased density of operations.”

Next-Gen Vehicles Built for Safety

Cutting edge developments on the avionics side are matched by innovations on the aircraft themselves. As Archer Aviation engineers develop the company’s full-scale eVTOL aircraft, Maker, they are learning valuable lessons about how to prioritize safety and power while balancing commercial factors such as component availability.

The company’s Meru battery pack is designed to maximize energy within mission constraints, such as power required for vertical takeoff and landing, in addition to safety and cyclizing cost requirements.

“There are really interesting future battery technologies, lithium metal, silicon anodes, etc. that have great promise but aren’t ready for commercialization yet,” said Geoffrey Bower, Archer’s chief engineer. “We’re taking the pragmatic approach using the cells that are available today, in production, at relatively low cost, while factoring in that our batteries will have higher power requirements and, at the pack level, more stringent safety and reliability type requirements than similar technology for the automotive sector.”

Maker has six independent battery packs that are each connected to two of its 12 motors, and the aircraft is designed to be tolerant to the failure of one of those packs. Redundancy, battery management system, accurate state of charge and health estimations, thermal runaway propagation prevention — these are all elements that the Archer team considers as it builds to certification requirements.

Bower is quick to note that redundancy itself does not guarantee safety; the team is equally focused on reliability of individual components and having the right quality assurance systems in place throughout the organization to maintain and improve safety.

“We’re also considering things like similarity of different processing chips, different software development teams — those are all things we’re thinking about from a safety and reliability standpoint,” he said.

Advanced Safety Testing

Testing can be one of the most expensive and challenging parts of next-gen aviation development. Aurora Flight Sciences, a Boeing Company that creates advanced aircraft and autonomous flight systems, is reducing friction in this space with its Centaur optionally piloted aircraft (OPA).

Based on a general aviation aircraft, Centaur provides a test platform with large payload capacity and streamlined access to the NAS with Aurora’s Airworthiness certificate.

“Centaur can operate in piloted, remotely piloted, or hybrid flight mode,” said Carrie Haase, executive lead, Flight Operations. “In hybrid mode, Centaur is controlled from a ground station while also carrying an on-board safety pilot to comply with regulations and ensure a safe flight. With an on-board safety pilot, testing can more easily be done, eliminating the need for time and cost-intensive travel to a remote test site.”

This summer, Centaur participated in testing with regulators to better understand the impact of large BVLOS operations in the NAS.

Haase notes that the company’s approach to autonomous flight system safety testing, which informs its support of a wide variety of Boeing next-gen projects, does not necessarily revolve around the absence of humans.

“Rather, it means decision-making for and with humans to perform in a trustworthy way,” she said. “We put experienced aviators on- or over-the-loop and in teams with unmanned systems in realistic simulations to test architectures, interface models, and interact methods against relevant scenarios.”

Also facilitating more streamlined testing practices is the increasing availability of certified, low-SWaP (Size, Weight, Power) components that allow manufacturers to focus their R&D efforts elsewhere.

“Up until recently, most of our potential customers have said ‘This is interesting but we’re not ready to deal with that yet — we’re worrying about getting our aircraft to fly,’” said Furey. “Now that they’ve gotten their aircraft to fly, they have to worry about the components required to fly their operations.”

Companies like Sagetech, UAV Navigation and uAvionix are reducing headaches by providing certified and certifiable avionics designed to minimize the amount of required onboard infrastructure.

“That’s critically important for reducing cost to the end user and conveniently translates much better into the AAM market where SWAP is at a premium,” said Ramsey. “Saving grams and milliwatts is much more important to them than to a GA operation.”

Refining the Human Factor

“In the remotely piloted world, you don’t have a shared fate — but you’re still operating an advanced technology in complex airspace,” said Joshua Olds, president of the Unmanned Safety Institute (USI), which provides remote pilot education and certification.

The “shared fate” refers the relationship that pilots have with manned aircraft. This is a psychological difference that remote pilot training must account for, he says, to help practitioners fully understand how their actions reverberate in the NAS.

Unmanned safety training organizations like USI are contributing to the maturation of the sector by building unmanned education around tried and tested aviation safety practices. “We can learn a lot from history,” says Olds, who notes that the most successful unmanned programs are run by existing aviation flight departments or longtime aviators.

“There are so many parallels, such as the importance of maintaining a sterile flight deck even though you’re not ‘in’ a flight deck,” he said. “Crew resource management, aeronautical decision making, human factors — these are topics that are very familiar in traditional aviation and are critically important when geared to remotely piloted aircraft.”

As unmanned operations grow in complexity — such as companies receiving federal waivers for BVLOS or night operations — so does the knowledge required to safely mitigate the corresponding risks.

Olds provides an example of a BVLOS infrastructure inspection operation. To safely achieve the mission goals, technicians must ensure the technology will operate as intended, crew members must brief pilots on potential infrastructure (or lack thereof) that could impact command and/or control, and pilots must know how to act on this information.

“To become as risk-averse as possible requires embedding the knowledge and the skill-based perspective from not just the remote pilot’s perspective, but also the technician and flight planning perspectives to reduce or mitigate both ground and airborne risks,” said Olds.

Poised for the Future, Delivering Benefits in the Present

The industry’s full-throated effort to prove the safety of future technology is providing commercial opportunities right now. Products like Daedalean’s visual systems — which are already available to help enhance the safety of manned operations — exemplify this confluence of immediate benefit and long-term potential.

“While we prove in the GA market that this technology makes a great copilot, we build up the evidence that it could be a good first pilot too,” said van Dijk.

Efforts to enhance the safety of existing flight systems are intertwined with development of next-gen technology, said Ramsey, noting that the sector’s focus on low-power, low-cost solutions has resulted in some of the core engineering technologies the company uses for both GA and unmanned aircraft.

“We’re looking to take this technology we’ve certified for GA primary instrument use — if you lose other systems in your cockpit, these IMUs and displays are safe enough to get you home — and see how it can be leveraged in AAM,” he said.

Technology is also helping the industry visualize its future infrastructure. Archer Aviation’s proprietary Prime Radiant data tracking and simulation software projects future demand for UAM flights — optimizing routing of an aircraft through a city, determining the most efficient battery charge cycle, and providing a glimpse of how to assign passengers to vertiports and aircraft.

“We’re pulling in data sources to understand where people are travelling within cities, where to put the vertiports to address existing demand, and to zero in on vehicle requirements to see which trips provide the most value to passengers,” said Bower.

The forward-thinking nature of products like Prime Radiant sums up the state of the future aviation sector — always looking ahead to what’s next, even as it works to answer the questions that will open those doors.