Perhaps more than any other major aerospace supplier, Honeywell has focused its efforts on supporting the companies developing eVTOL aircraft, providing a wide range of products to a growing list of customers.
On June 18, 1914, Lawrence Sperry of the Sperry Corporation performed a spectacular demonstration of his new invention, the gyroscopic autopilot, before a crowd assembled on the banks of the Seine River in France. Not content to simply lift his hands off the controls, Sperry actually left his pilot seat and crawled onto the wing of his Curtiss C-2 biplane to display his confidence in the device, launching a new era of automatic flight control.
More than a century later, some things have changed. Test pilots are now generally encouraged to remain in their seats, and the Sperry gyroscopic stabilizer business has long since been absorbed by Honeywell Aerospace. But Lawrence Sperry’s legacy is still going strong. Today, the aviation industry is as dynamic and pioneering as it was in 1914 thanks to a proliferation of new electric vertical take-off and landing (eVTOL) models, and Honeywell is at the forefront of efforts to make these novel aircraft safe and easy to control.
In June 2019, Honeywell introduced a compact fly-by-wire flight control computer targeted specifically at this emerging eVTOL and urban air mobility (UAM) market. At roughly the size of a book, the device packs most of the capability of Honeywell’s much larger systems for transport-category aircraft, such as the Boeing 787. It shares their redundancy, too, with a triplex flight control computer architecture and lockstep processing (adding an additional identical processor to a system that monitors and verifies the operation of the primary processor to achieve high reliability).
And it’s only one of several new products that Honeywell is developing for the UAM space. Another is the IntuVue RDR-84K Band Radar System (see sidebar), a lightweight, phased-array radar that could help enable the detect-and-avoid capabilities necessary for autonomous flight. There’s also the AH-2000 attitude and heading reference system (AHRS) with a micro-electromechanical system (MEMS) design to enable navigation in urban canyons and other GPS-denied environments.
The list goes on. Honeywell is developing robust electromechanical actuators for this new generation of fly-by-wire aircraft, in which traditional hydraulic actuators would carry an unacceptable weight penalty. The company is adapting its HTS900 gas turbine engine for hybrid-electric applications and has partnered with the automotive supplier Denso on electric propulsion systems. It’s also experimenting with new types of avionics and flight control interfaces for simplified vehicle operations (SVO) to enable urban air taxis to be flown at scale with reduced pilot training requirements.
Clearly, when it comes to the “Electric VTOL Revolution” — as VFS describes it — Honeywell is “all in.”
“When you look at the traditional Honeywell business, there are many, many aircraft that have Honeywell equipment on them. But when we look as a company, we need to be creating new innovations, going into new market spaces,” explained Honeywell VP of cockpit systems Mike Ingram.
Honeywell has been particularly encouraged by the fact that the UAM market is attracting both new players — including Honeywell customers Vertical Aerospace and Jaunt Air Mobility — and traditional manufacturers, such as Bell and Airbus. Rather than get left behind, Ingram said, Honeywell wants to show that it’s a “market leader” bringing “market-leading technology” to this exciting new space.
Bringing Its Legacy into the Future
Honeywell’s sprawling complex at the Deer Valley Airport in north Phoenix, Arizona, is more than just a corporate campus — it’s a living chronicle of the recent history of avionics. Hidden within its warren of offices are laboratories for each of the Honeywell cockpits still flying, allowing the company to support its products throughout their life cycles.
“We’ve been certifying software and complex hardware devices for many years, since software has been created,” Ingram pointed out. That rich legacy of aerospace product development and certification is what Honeywell believes will differentiate it in the eVTOL space. Many new players in the market are working upward from the types of hardware and software used on small drones, but these could prove impossible to certify for passenger-carrying applications.
“Safety is just absolutely paramount,” emphasized senior engineering program manager Dereck Clark. “It’s always paramount, but for this market space too, with the potential for many vehicles out there flying around heavily congested urban areas, safety will be absolutely needed.”
For that reason, Honeywell is designing its UAM products to the same levels of safety and reliability demanded for transport-category applications. The trick is to squeeze this robustness and redundancy into a package small enough for one- to five-passenger eVTOL aircraft, where every ounce counts. This is where Honeywell’s engineering innovation comes in.
Honeywell has a few factors working in its favor, including Moore’s Law. Given the traditionally slow pace of aerospace certification, many of Honeywell’s newer avionics were initially designed around a decade ago. By starting from scratch with its UAM products, Chava said, “we’ve taken advantage of the latest technology that’s available, all the modern processors and modern components.”
Meanwhile, Honeywell is able to leverage its enormous resources as an aerospace-industry giant to rapidly iterate new products. For example, to flight test its new RDR-84K radar system, Honeywell used the Airbus AS350 helicopter in its hangar full of dedicated flight-testing aircraft, across the street from its Deer Valley office complex. Those types of synergies simply aren’t available to scrappy startups.
However, Honeywell realizes that there are also some disadvantages to being a large legacy company, so it has been working hard to adapt to a new, nimbler way of doing business. According to Chava, the urban air mobility customers that Honeywell is working with are “challenging the status quo every single day. They want speed, and they want innovation, and I think we’re rising up to that challenge.”
Chava said that Honeywell has made far-reaching changes to its internal processes — “from how we develop our products to how we write our contracts” — to better function in this fast-paced environment. “We cannot do business the way we have been doing traditionally and make this industry move faster,” she said.
Rethinking the Vehicle-Pilot Interface
For urban air mobility to truly take off, eVTOL aircraft will need to be more than clean and quiet. They’ll also need to incorporate unprecedented levels of autonomy and interact with the humans inside them in fundamentally new ways.
The Urban Air Mobility: Economics and Global Markets study released in August 2019 by NEXA Advisors — jointly sponsored by VFS and other partners (see “NEXA Completes Landmark Urban Air Mobility Study, Focuses on Infrastructure,” Vertiflite, Nov/Dec 2019) — describes a UAM “inflection point” when higher levels of automation in vehicle operation and air traffic control will unleash the full potential of this nascent industry. At that point, nominally in the 2030-2040 time frame, “the cost structure of the entire industry will be dramatically reduced in synchronization with the expansion of vehicle and airspace capacity,” pushing the sector to full profitability, according to the report.
Getting to that inflection point is not simply a technological challenge: it’s also a social one. Before passengers feel comfortable stepping into a fully autonomous aircraft, there will likely be a transition period when UAM aircraft have human pilots. But it simply doesn’t make sense to design these fly-by-wire aircraft with conventional pilot interfaces — not when new technologies enable simpler, more efficient forms of aircraft control. Simpler controls could also permit safe operations with much less pilot training, reducing costs and greatly expanding the potential hiring pool.
At its Deer Valley campus, Honeywell is experimenting with these new approaches to flight controls in its Tool for Rapid Aircraft Control Simulation (TRACS) lab. Here, researchers are using both a traditional (non-motion) flight simulator and a virtual reality sim to explore how pilots might control eVTOLs in the future.
In a conventional aircraft, pilot control inputs translate directly to specific movements of flight surfaces. But in the TRACS lab, Honeywell has developed a system in which pilot controls are used instead to provide more general commands — such as moving a cursor on a screen to say “fly here” — which the flight control computer then determines how to execute.
“You still get a response and a similar flight path to flying direct,” said chief scientist John Suddreth, during a simulator demonstration of a generic eVTOL on an approach to landing. One difference: “I don’t overshoot because I’m not controlling the aircraft [directly].”
In such a system, the displays and symbology presented to the pilot take on additional importance. As it moves into this new world of aircraft control, Honeywell is heavily leveraging its experience with integrated flight decks for conventional aircraft, including the Primus Epic cockpit on the Leonardo AW139 helicopter. In particular, Honeywell’s work on synthetic vision and an intuitive symbology may inform its development of avionics for eVTOLs.
According to Jason Bialek, product-line director for the Epic 2.0 and 2.0+ integrated flight deck, Honeywell cockpits have flown over two million hours on the AW139. “All of that experience and expertise is very important in providing something easy to use,” he noted. Honeywell believes that here, too, it can provide a valuable service for eVTOL startups, since for them to replicate these capabilities, “there’s a lot of learning and development that would happen for that small team.”
Honeywell’s UAM Radar
Honeywell recently completed another round of flight testing on its IntuVue RDR-84K, a compact radar system that is being targeted to the urban air mobility market.
Mounted on an Airbus AS350 helicopter, the radar system was flown out of Honeywell facilities in Phoenix, Arizona, over a three-week period in October and November. According to flight test personnel, the test program took the aircraft over roads, power lines and towers, and over and around mountains and canyons, to evaluate the RDR-84K’s ability to detect obstacles and terrain. The helicopter also performed multiple flights with designated “intruder aircraft” to test the system’s ability to detect other air traffic.
This was Honeywell’s second flight test campaign for the RDR-84K, following an initial round of testing about a year-and-a-half ago. Those tests laid the groundwork for NASA’s own flight-test program using the radar, which launched this summer. NASA has mounted the system — which it is calling Digital Active Phased Array, or DAPA-Lite — on a fixed-wing TigerShark drone, with the goal of informing minimum operational performance standards for detect-and-avoid systems on unmanned aircraft.
As Honeywell project manager Bindu Chava explained, the radar system is “a key enabler for us as we move more towards autonomy, because at that time you won’t have a pilot navigating.” However, Honeywell also expects the radar system to be used on piloted aircraft before then, including early eVTOL models, as well as more conventional aircraft types. The system could also have applications on military ground vehicles.
The RDR-84K has a phased array design in which radio waves are steered electronically, eliminating the need for moving parts. It uses multiple beams that scan simultaneously, allowing it to detect different inputs, such as other aircraft, terrain and landing zones at the same time. According to Honeywell, the system is software adaptable so that users can customize its operation and performance parameters — adjusting the radar’s range, for example, or instructing it to focus on certain types of objects.
Honeywell announced in June of this year that it had signed an agreement with an unnamed air taxi developer to supply multiple RDR-84K units for the developer’s prototype aircraft. Chava declined to specify that developer, but confirmed that the radar system is also being flight tested on customer aircraft.
Partnering for Success
In November, the Swiss startup Daedalean announced that Honeywell had entered into a financial and technological partnership with the company to further develop its software for autonomous flight control and vision-based navigation. Daedalean is basing its flight-control software on artificial intelligence (AI), opening up a new world of both capabilities and certification challenges.
“It’s going to challenge the authorities,” Honeywell’s Mike Ingram acknowledged of AI. Unlike conventional avionics software — in which a given input reliably produces a specific output — AI doesn’t exhibit the same determinism. “Autonomy is really about the computer being able to make decisions on its own and being able to do things that you haven’t always programmed it to do, but it can do those in a safe way,” Ingram continued. “When we go into autonomy and the way that we code… it’s going to take a whole new training and a whole new learning for the industry as well as the FAA [Federal Aviation Administration].”
The partnership with Daedalean exemplifies the collaborative approach that Honeywell is taking to the UAM market — one that may well be critical to the success of the industry as a whole. Just as Honeywell wants to help eVTOL developers shorten their paths to market by providing them with safe, certifiable components, the company is eager to speed its own development processes by leveraging outside expertise. Meeting the industry’s aggressive timelines will require nothing less.
“Even though Honeywell is a big company with a lot of products, we know we can’t do it all,” Ingram said. “And the more collaboration partnerships we get, the more successful we can be, as well as everyone in the industry can be.”
About the Author
Elan Head is a freelance writer and serves as the special projects editor for Vertical Magazine, having previously served as its editor-in-chief. She is also the managing editor for Vertical’s eVTOL.com website and a frequent contributor to Vertiflite. Head is a commercial helicopter pilot and flight instructor who has flown in the US, Canada and Australia.
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