Advances in 3D design, simulation and validation tools are spurring aerospace efforts to improve the safety and reduce the time, costs, complexity, and staffing demands of certification projects. That work should help bring new and upgraded aircraft, improved systems, and components to market.
Several other factors are adding to the impetus of those efforts, according to industry leaders.
Digital transformation — including the broader adoption of digital engineering, model-based design, and virtual copies (or digital twins) of new products and operations — has become a priority for nearly every major aerospace and defense firm. While the pace of adoption varies, firms are lured by the prospect of such advanced capabilities helping add billions to annual earnings through greater enterprise efficiencies and increased sales.
“Companies can’t afford to have a big design change in the middle of their flight test program. It might add six, eight months of delay to their program and a lot of cost,” said Dale Tutt, Siemens Digital Industries Software’s vice president of industry strategy. His 30 years of engineering and program management experience at The Spaceship Company, Cessna, Bombardier and General Dynamics showed that “using simulations, using the digital twin to really prove out your systems before you get into flight test, has tremendous benefits,” he said.
Uncertain economic and geopolitical conditions, combined with persistent supply chain problems, have companies seeking ways to streamline critical hardware and software pipelines while heading off problems before they disrupt operations.
Dassault Systèmes, a world leader in 3D modeling, social collaboration, simulation, and information intelligence technologies and services, provides customers “a virtual experience platform.” Its customers’ business environment remains volatile,” deputy CEO and chief operating officer Pascal Daloz, said. “To increase agility and profitability,” clients are turning to the company “to enable real-time analysis of raw material and part substitutions, as well as the reshaping of value networks.”
Like most industries across the globe, aerospace and defense firms feel compelled to reduce their environmental impact. They are adopting “greener” means of conducting their own activities and customers’ operations of their products. These sustainability efforts are “driving a reimagining of portfolios throughout manufacturing industries,” Daloz noted. “There is a race to innovate across all subsectors.”
One example is Rolls-Royce, which has committed to achieve net-zero carbon emissions from its own operations by 2030. It also aims to create propulsion and energy breakthroughs that help customers reach net-zero carbon emissions by 2050. The company’s net-zero path is built on three pillars, according to its Engineering Group head of systems and software, Jonathan Cooper.
Those are the electrification of aviation, the development of small, modular nuclear reactors, and the construction of electrical microgrids. The latter are focused on generating and transmitting the power needed to charge electric aircraft.
“The electrification of aviation is what really is driving Rolls-Royce,” Cooper said. He added that those pillars will depend on precise, safety-critical control systems that Rolls-Royce is designing with the mathematical computing software tool set of MathWorks, a leading developer of such advanced capabilities.
A key consideration in modeling and simulation, particularly advanced capabilities, is the credibility of tools and processes and their data products. The test, explained Aeroelasticity Professor Guiseppe Quaranta at Milan, Italy’s Polytechnic Institute, is whether a project manager or regulator can say, “I am comfortable making the needed decision with this data.”
That was one lesson of two parallel efforts over the last several years. Both sought to lay the foundation for persuading U.S., European, and other airworthiness authorities that 3D design, modeling, and simulation capabilities have become reliable enough to replace many flight tests used to certify new and upgraded aircraft, systems and components. They were inspired by dramatic improvements since the late 1990s in the ability of numerical analysis methods — computational fluid dynamics (CFD), computational structural dynamics (CSD), computational fluid mechanics (CFM), and flight simulation — to capture the physics of aircraft in flight. Those improvements were enabled in part by increases in computation power and speed, more efficient coding, and the expanded foundation of flight and wind tunnel test data against which to assess analytical results.
Proponents argued that these tools were used every day “to analyze, optimize and design every external surface of an aircraft” and their growing accuracy warranted broader use.
The first effort began in mid-2017. Representatives from Boeing, Airbus, the Federal Aviation Administration (FAA), the European Union Aviation Safety Agency (EASA), the German Aerospace Center (abbreviated DLR), and NASA began work to develop a “recommended practices” document to support use of advanced analyses as an acceptable means of complying with a new or modified aircraft’s flight-safety requirements.
They met monthly for about a year. A larger “community of interest” group, which included representatives of Embraer and several universities with aeronautical engineering departments — working under the American Institute of Aeronautics and Astronautics (AIAA) — then took up completing the Certification by Analysis (CbA) document. The group identified six recommended practices for an applicant to accomplish when flight modelling is being developed, proposed, and used to reduce flight testing relative to established aircraft certification practices.
At about the same time in Europe, a group was formed to address the application of advanced analyses to the certification of helicopters and tiltrotors. Led by the Italian aerospace, defense, and security manufacturer Leonardo, this Rotorcraft Certification by Simulation (RoCS) project included EASA, Germany’s DLR, the Netherlands Aerospace Center (abbreviated NLR in Dutch), the U.K.’s Cranfield University and University of Liverpool, and Milan’s Polytechnic Institute (Politecnico di Milano in Italian). That institute served as coordinator of the project, which was funded by the European Union’s Clean Sky 2 program to speed the integration of technologies to reduce aircraft pollutant and noise emissions.
The efforts were driven by several factors, according to participants and their documents.
– Certifications of new aircraft and of derivative models, for example, have relied almost exclusively on flight tests (particularly in demonstrating handling-qualities compliance). Certification by simulation was limited to some failure modes.
– Certifications were becoming more expensive and taking longer as the complexity of aircraft and their systems increased.
– Flight tests involve inherent safety risks, particularly when they address operations at the edges of the flight envelope or more severe failure scenarios.
– Flight tests by their nature involve the most knowledgeable and skilled pilots, maintainers, and operations personnel. They therefore are not representative of how aircraft may perform when operated by more varied groups of personnel.
Proponents argued that greater use of certification by analysis or simulation would result in safer, less costly product development and approval and bring innovative products to market faster, with designs more suited to the actual population that would put them in service.
Based on the CbA group’s work, the AIAA published a recommended practice (AIAA R-154-2021) for using flight modelling “to reduce flight testing supporting aircraft certification.” It outlines six tasks to accomplish when developing, proposing, and using numerical analysis as an alternative to “established aircraft certification practices.” The document focuses on certification requirements for aircraft performance and handling qualities, static loads and aeroelastic stability. It can be applied to other requirements, AIAA says.
The rotorcraft project in March published the third update of its preliminary CbS guidance. It presents a structured process, starting with the pertinent EASA rotorcraft certification specifications, that outlines the steps in building a certification plan using a flight simulation model, flight simulator, and flight test measurement system (which feeds the flight model and simulator development “with real-world test data to support validation and fidelity assessment.”) Quaranta was scheduled to brief the rotorcraft industry on the project’s latest work in mid-May at the Vertical Flight Society’s annual forum in West Palm Beach, Florida.
Other recent 3D, simulation and validation news includes Siemens Digital Industries Software’s expansion of its long-term partnership with IBM. The partners plan to jointly develop a solution that integrates their respective systems engineering, service lifecycle management and asset management offerings. The SysML v1 standards-based suite of integrated engineering software is aimed at supporting traceability and sustainable product development. Siemens said it will use a digital thread linking mechanical, electronics, electrical engineering and software design and implementation. The objective is to span the product lifecycle, from early design and manufacturing to operations, maintenance, updates, and end-of-life management. Initially, the companies are working to connect IBM Engineering System Design Rhapsody for systems engineering with Siemens’ Xcelerator portfolio of software and services, including Teamcenter software for product lifecycle management and Capital software for electrical/electronic systems development and software implementation.
The pairings are intended to help customers address increasing competitive pressures, tight labor markets, and growing environmental compliance objectives, Siemens said, by allowing them to adopt a more holistic management approach.
On the sustainability front, Siemens in 2022 acquired aeroelastic simulation solutions specialist ZONA Technology. The company said adding ZONA technology to its Xcelerator portfolio will help customers make their digital threads more comprehensive and efficient, enabling them to speed innovation as well as ensure on-time and on-budget delivery of products supporting the global drive toward climate-neutral aviation.
Dassault Systémes’ latest efforts go well beyond the atmosphere. Under a new pact with the European Space Agency (ESA), it will bring its advanced tool suites to European companies aspiring to a place in the “New Space” economy of commercialized space operations.
The pact aims to build on a collaboration agreement signed in January 2022 with ESA Business Incubation Centers (BICs) in Bavaria and Northern Germany. The earlier deal made Dassault Systémes a technical industry partner; it offers companies working through those centers its licensed software applications as well as networking and communication opportunities through its 3DEXPERIENCE Lab, an open innovation laboratory and accelerator program.
The new deal calls for Dassault Systémes and ESA to work together in nurturing and accelerating new space startups within the BIC network in Europe.
MathWorks, in addition to helping Rolls-Royce develop safety-critical control systems supporting broader electrification, has aided impressive work in the cosmos. Last year, it helped space engineers steer a spacecraft to the first-ever planned collision with an asteroid, part of a fledgling Earth-defense effort.
On Sept. 26, NASA’s Double Asteroid Redirection Test (or DART) spacecraft crashed into a 492-foot-wide asteroid called Dimorphus. DART was a test to see if the space agency might one day deflect a space rock from colliding with Earth (an event believed to have killed off the dinosaurs 66 million years ago.)
The nearly 1,300-pound DART’s collision at 14,000 mph changed Dimorphus’ orbit only slightly. But the mission was considered a success because DART flew just over 10 months and looped 297.5 million miles through space before it hit its target 11 million from Earth. Its autonomous guidance system, the Small-body Maneuvering Autonomous Real Time Navigation (SMART Nav), steered DART into the asteroid, with no human intervention for the last four hours of its flight. SMART Nav was developed in MathWorks’ MATLAB and C++.
Independent software vendor Parasoft has specialized in automated software testing and application security for over 30 years. The numerous industries it serves include civil aviation, particularly compliance testing to the DO-178C standard (for commercial software-based aerospace systems) and the DO-278 standard (for communication, navigation, surveillance, and air traffic management software-based systems).
One of Parasoft’s objectives is to help customers reduce complexity by providing them with unified kits that integrate various software tools to save them time and money. Its C/C++test is the fully integrated software testing solution for embedded safety-critical industries, the company says.
Parasoft’s customers have included Alaska Airlines, Boeing, Lockheed Martin, Northrop Grumman, NASA, and Wyle Laboratories. Parasoft worked with Lufthansa Cargo AG to streamline its shipment database for company-owned and chartered freighter flight operations. The German operator wanted a software application that would provide a stable, central control capability for managing cargo service performance without adversely affecting the systems that front-line staff use in feeding and extracting packages and data throughout the cargo network.
Parasoft used its testing expertise to develop an application programming interface (API) to enable various cargo systems to work with the new shipment database without degradation. Working with the Lufthansa Cargo team, Parasoft testers and their tools reduced the regression testing required to field the new system by at least 20 percent compared to manual regression testing, the company said. Regression testing is the process of assuring that new software code can be implemented without causing a loss of functionality (or regression) in existing systems.
Enhanced 3D design, simulation, and validation capabilities continue to change aerospace product development. Leonardo’s helicopter division, for instance, has used CbS to meet specific certification requirements of its AW169 and AW189 models. Now, the division has opened a Virtual Development Environment, based at its Cascina Costa, Italy headquarters and Yeovil, U.K. manufacturing and engineering facility. Embedded in a Digital Simulation Laboratory, that environment leverages advanced simulators that use the avionics and software of actual aircraft to test new capabilities before they are flown. Its ongoing efforts to field the AW609 tiltrotor and develop Clean Sky 2’s Next Generation Civil Tilt Rotor (NGCTR) are benefitting from certification by simulation techniques.
“The benefits it brings are huge: reducing cost and time, increasing safety, optimizing synergies across departments and geographies,” said the helicopter division’s managing director, Gian Piero Cutillo. “I’m really pushing very hard on this.”