Honeywell Aerospace recently revealed its latest developments in avionics technologies at its new Advanced Air Mobility Lab in Phoenix, Arizona
Honeywell Aerospace recently revealed its latest developments in avionics technologies at its new Advanced Air Mobility Lab in Phoenix, Arizona. The company’s aerospace engineering team has focused on enabling communications, navigation, and surveillance systems for unmanned aircraft and electric vertical take-off and landing (eVTOL) vehicles. At a preview event in April, in advance of the lab’s formal opening, experts offered attendees insights into Honeywell’s compact fly-by-wire systems, detect-and-avoid radar, SATCOM, and other components that are optimized for use in advanced air mobility (AAM) aircraft.
The compact fly-by-wire flight control system is one example of how Honeywell has scaled down a system used in conventional aircraft. Jia Xu, senior director of strategy for urban air mobility (UAM) and unmanned aircraft systems (UAS), shared the process that has gone into developing a compact, purpose-designed fly-by-wire system. “The fly-by-wire system on a big aircraft is hundreds of pounds.” To scale down the system for UAS, he said, “We have to be smart in thinking about what the system could be and what the essential functions are that it must perform.”
A key feature of the fly-by-wire system, according to Xu, is the built-in flight safety envelope protection. “The aircraft is always kept in the safe zone of operations,” he explained. “Because the flight control and how you interact with the aircraft becomes more software-defined, you can customize it. We can also make the control intuitive and safe.” The pilot’s decisions can be translated simply and accurately into the fly-by-wire logic in the onboard, and to the aircraft’s actuators and motors. Xu continued, “This is the kind of technology that we have demonstrated and that the industry has demonstrated across a large class of commercial aircraft, brought down to the form factor that works with UAM and UAS vehicles.”
Douglas Martens, director of OEM sales and new business development for Honeywell Aerospace, commented that the compact fly-by-wire system is designed with redundancy and triple dissimilarity—each box has a different hardware configuration—which allows for a simplified control system. “The pilot doesn’t have to manage a throttle and thrust traditionally; it’s all been simplified.”
To scale down a system like the fly-by-wire for integrating into smaller aircraft, said Xu, they must leverage advances in computing. It is partly driven by improvements in hardware, and also by intelligently considering how to partition the functions of the fly-by-wire system among avionics, flight control, and actuation systems. The design processes for avionics in conventional aircraft translate easily to drones and eVTOL aircraft. “The functions are similar, but the vehicles are very different,” Xu commented.
For eVTOL aircraft, he said, “weight is still key, even more so than conventional aircraft,” because they must be able to carry the whole weight of the aircraft throughout the vertical lift-off phase. In tailoring avionics to smaller AAM aircraft, they’ve had to think creatively about the design of systems, boundaries, and architectures. “We also need to be leveraging advances in computing and miniaturization to make that happen,” Xu added.
Honeywell’s development of avionics systems for AAM aircraft has gravitated naturally towards making products smaller and lighter, said Andrew Barker, senior director of sales marketing for UAM/UAS. “Our organization, the UAM group, has only officially existed for a little over two years now, but a lot of the technologies that we’re now selling, utilizing, and continuing to develop already existed—whether they were drawing-board or early prototypes—and some were already commercialized.”
Another consideration for AAM aircraft is fuel management. In the next generation of electric-powered aircraft, the display of fuel usage information and communicating that data to the pilot will change, as well as performance estimation. Douglas Martens explained that weight is a key driving factor in the AAM market. An advantage of electric aircraft, he observed, is the constant weight; there is no need to calculate changes in weight as fuel is added or consumed like with conventional aircraft.
“In terms of shifting toward more autonomous operations in the future,” Jia Xu said, “when we think about cargo drone aircraft, and middle-mile cargo transportation, we have to think about the technology needs in terms of facilitating detect-and-avoid, which is why we’re innovating with the RDR-84K solution. We’re using our avoidance algorithms integrated into the loop to move the aircraft out of the way.” The next step, he added, is testing this technology on larger vehicles at full scale and integrating it into OEM vehicles.
The AAM lab featured a space dedicated to its RDR-84K radar system, presented by Lead Systems Engineer Larry Surace and by Andrew Baker, Senior Advanced Systems Engineer for Urban Air Mobility. The radar’s DAA algorithm calculates the speed of moving targets to determine when it needs to change direction in order to avoid collision. “There was no intervention from the pilot, who relinquished control of the drone to the radar,” stated Surace. “We flew it on multiple missions, at various altitudes, and at different angles. That allowed us to characterize how the radar was performing when it was put on a real drone.”
They plan to perform tests with the radar against multiple drones in multiple different scenarios. A more immediate goal for the team is to release the second version of the radar, which they expect to do by the end of June. The second version of the RDR-84K radar will weigh even less than the original version—about 1.5 pounds.
“We’re expecting a 2025 timeframe or sooner to integrate it on vehicles like drones for delivery,” Surace remarked. “We design for certification, and we’re in the process of working with the committees to understand how to get it certified, to show it will perform as designed in a safe manner.”
Andrew Baker emphasized the engineering involved in determining how to fly the radar. “You can’t just google how to put a radar on a drone,” he explained. “Cameras and LIDAR [light detection and ranging] are very common payloads for UAVs, but not radars.”
A radar technician can remotely connect to the RDR-84K radar while it is in flight and quickly change various parameters, meaning that the team doesn’t waste time bringing the vehicle back to the ground, noted Baker.
Honeywell’s solution for satellite communications, the Small UAV SATCOM system, is the lightest and most compact SATCOM solution on the market, Jia Xu said. “The whole package, including the antenna and the computing unit, is 1 kilogram. That’s still a little bit large for the smallest drones, but for a variety of enterprise and larger-scale drones, as well as for middle-mile cargo aircraft and UAM vehicles, it’s a very convenient package to provide connectivity.” Despite the modest bandwidth the product offers due to its very small fixed antenna, “there are certainly options for continuing to develop that small technology, keeping the size the same but increasing the bandwidth capability of the system,” Andrew Barker added.
Pulkit Agrawal, principal certification engineer for Honeywell Aerospace, demonstrated one of the interactive flight simulators in the AAM lab. “This simulator does both vertical take-off and landing automatically; we haven’t developed the system for automated take-off and landing yet,” he explained. With simplified vehicle operations (SVO), the time required for training pilots will be significantly reduced. “Someone who is not a pilot can fly it very easily, and doesn’t have to worry about things like flight control or speed,” Agrawal added.
Systems engineer Jose Anaya guided attendees in operating a second flight simulator at the AAM lab. The main difference with UAM aircraft is the transitional phase, Anaya said. Once commercially available, Honeywell’s SVO will include pre-loaded flight plans for emergency landings or detours. This ensures that even inexperienced pilots will still be able to safely operate the aircraft.
Improvements to SVO make the user interface less complex with each iteration, and this enables remote operations even for some of the larger AAM aircraft. Douglas Martens shared that Honeywell’s Anthem flight deck now has a highly connected architecture that allows for a lot of onboarding and offboarding of data, with ground infrastructure supporting communications. “The large cargo drones like Pipistrel’s will have to have some command and control capabilities from the ground station,” he said. “When the pilot’s on board, it’s more about receiving ATC communications and stuff like that, so there needs to be more connectivity to ground ATM infrastructure to allow seamless electronic transmission of data.”
The Honeywell Anthem solution enables increased computing capability, said Freddy Gonzalez, senior engineering manager for AAM. “On the avionics side, we did go to a quad core processor,” he explained. The AAM aircraft that use Honeywell’s avionics “are going to be piloted, and they’re going to use the same certifications that exist today. But we are driving simplified vehicle operations, and we’re going to work with regulators to reduce what the pilot has to do, such as uploading the flight plan from a ground station.”
