The drive to decarbonize aviation has taken a bold step forward as Lufthansa, Air France, and Singapore Airlines prepare to collaborate on real-world trials of CFM International’s revolutionary open fan engines under the RISE (Revolutionary Innovation for Sustainable Engines) program. Backed by Airbus and regulators in Europe and Asia, the initiative signals that the industry’s most radical engine architecture in decades is moving from the wind tunnel and test stand into the operational realm of airports and airline fleets. For travelers, it points toward a future of quieter cabins, lower emissions, and potentially transformative changes in how next generation aircraft look, sound, and fly.
From Concept to Cockpit: How Open Fan Engines Reached Takeoff Speed
Open fan propulsion, sometimes called an unducted fan or open rotor, is not a completely new idea. The concept was explored in the 1980s, when fuel prices and environmental concerns first pushed engine makers to experiment with exposed, propeller-like fan stages that promised big efficiency gains. At the time, however, noise, vibration, and certification complexities kept the technology from entering mainstream commercial service. The industry returned to more conservative turbofan designs, focusing on incremental improvements rather than radical rethinks.
The difference today is the urgency and scale of the climate challenge. Airlines and manufacturers have committed to net zero carbon emissions by 2050, which requires cutting fuel burn dramatically on the single aisle jets that form the backbone of global fleets. CFM’s RISE program, launched in 2021, is the centerpiece of this new push. The open fan demonstrator aims to reduce fuel consumption and carbon dioxide emissions by more than 20 percent compared with today’s most efficient narrowbody engines. Those gains come from a larger, slower-turning fan with advanced composite blades that move more air at lower energy cost.
In parallel, Airbus has spent the past several years evaluating how such an engine would integrate with future aircraft. High and low speed wind tunnel campaigns in France and the Netherlands have tested scale models of the open fan on wing, measuring aerodynamic behavior and acoustic performance across takeoff, cruise, and landing conditions. Safran, CFM’s French parent, has run intensive ingestion, endurance, and blade integrity trials, putting advanced composite fan designs through hundreds of hours of punishment to prove their durability and safety in an unducted configuration.
These ground and lab efforts laid the foundation for the next milestone: flight tests on a dedicated Airbus A380 flying test bed late this decade. Mounted at the rear of the superjumbo, the open fan demonstrator will allow engineers to correlate wind tunnel predictions with real-world aerodynamics, vibrations, and noise. The new airline partnership around Lufthansa, Air France, and Singapore Airlines does not replace that program. Instead, it extends the test envelope into the operational environment of busy international hubs and frontline airline engineering teams.
The Lufthansa, Air France, and Singapore Airlines Role in the Test Campaign
While CFM, Airbus, and regulators shape the technical and certification roadmap, airlines are crucial in turning a promising technology into a commercially viable product. Lufthansa, Air France, and Singapore Airlines are expected to participate by providing operational data, engineering expertise, and eventually aircraft platforms capable of hosting pre-production engines once they move beyond the A380 demonstrator phase. For these carriers, the appeal is both environmental and strategic, combining sustainability leadership with the opportunity to influence the specifications of a powerplant that could eventually replace large parts of their single aisle fleets.
Each of the three airlines brings a distinct perspective. Lufthansa has positioned itself as a test partner on advanced efficiency technologies, from biofuels to aerodynamics and cabin retrofits. Air France, as part of a major European group with hubs tightly regulated on noise and emissions, has strong incentives to back solutions that reduce the environmental footprint of short and medium haul operations. Singapore Airlines, through its home hub at Changi, sits at the center of Asia-Pacific connectivity and has been active in sustainable aviation fuel initiatives and operational efficiencies that make long range flying more sustainable.
The anticipated collaboration with CFM would see engineers from these airlines involved in defining maintenance concepts, ground handling practices, and fleet integration scenarios for open fan powered aircraft. Their feedback will help determine how the engines are monitored in service, how quickly they can be turned around at the gate, and how airport infrastructure might need to adapt to accommodate their unique geometry and acoustic profile. From a traveler’s perspective, the airlines will also be instrumental in shaping how the cabin experience evolves, from noise levels to seating layouts and boarding procedures on next generation aircraft.
Although final test schedules and specific aircraft allocations will be shaped over the coming years, the strategic intent is clear. By committing early to CFM’s open fan roadmap, Lufthansa, Air France, and Singapore Airlines are positioning themselves at the front of the queue for technology that could redefine the economics and sustainability metrics of medium haul travel in the 2030s and beyond.
Singapore’s New Role as a Global Testbed for Future Propulsion
Singapore’s emergence as a central stage for open fan trials adds a new dimension to the story. In early February 2026, the Civil Aviation Authority of Singapore signed a memorandum of understanding with Airbus and CFM International to establish the world’s first airport-based testbed focused on RISE technologies, with a particular emphasis on open fan engines. Rather than simply hosting flight demonstrations, the project will examine how these novel powerplants interact with every part of an airport ecosystem, from pushback and taxi procedures to safety zones and maintenance hangar workflows.
The testbed will involve operational trials at Changi Airport or nearby Seletar Airport once ground and flight test campaigns reach the appropriate level of maturity. These trials are designed to stress test the readiness framework that regulators and manufacturers are jointly developing. Questions such as how to tow an aircraft with a much larger unshrouded fan, how to position ground vehicles safely around the engine disk, and what kind of noise footprint to expect at different taxi speeds will be investigated using real hardware in a live airport environment.
For Singapore Airlines, whose operations are deeply entwined with Changi, participation in this testbed is a natural extension of its technology and sustainability strategy. As a home carrier, it will have a direct stake in ensuring that open fan operations can be conducted efficiently without compromising the airport’s reputation for smooth passenger flows and punctuality. The airline will also gain firsthand insight into how new engine architectures might alter gate allocation, turnaround buffers, and even route planning if performance advantages open up new nonstop city pairs or more efficient flight levels.
More broadly, the Singapore initiative illustrates how future propulsion will not be evaluated purely on the basis of fuel burn. For open fan technology to succeed commercially, it must integrate seamlessly into the choreography of a major international hub, from deicing stands to baggage loading zones. By providing a neutral test ground that can be used by airlines and manufacturers around the world, Changi is poised to become a reference point for how advanced engines are certified, operated, and standardized globally.
What Makes CFM’s Open Fan Engines Different
To understand why so many stakeholders are investing heavily in the RISE program, it is worth unpacking what makes the open fan design so distinctive. A conventional turbofan hides its blades inside a circular nacelle. Air is drawn into the inlet, compressed, mixed with fuel in a core, and then expanded through turbines and a fan to generate thrust. Over the past several decades, improving efficiency has primarily meant increasing the size of that fan and the proportion of thrust it produces, known as the bypass ratio. As fan diameters have grown, however, the weight and drag of the surrounding nacelle have become significant constraints.
The open fan concept tackles this by removing the nacelle entirely, allowing for larger diameter composite blades that sweep through the air largely unconstrained. CFM’s current demonstrator configuration uses a single rotating stage of variable pitch carbon fiber blades followed by fixed guide vanes. The result is a propulsive system that combines the speed and cruising altitude of a jet with the propulsive efficiency more commonly associated with modern turboprops. By optimizing blade shape, pitch control, and rotational speed, the engine can move a larger mass of air at lower velocity, which is fundamentally more efficient.
Beyond pure aerodynamics, RISE has been designed as a fuel flexible platform from the outset. The engine architecture is being developed to run on 100 percent sustainable aviation fuel and to be compatible with future hydrogen based systems, either as direct combustion or, over the longer term, as part of hybrid electric configurations. This makes the open fan more than a stopgap solution. It is a bridge technology intended to remain relevant as the fuel mix of commercial aviation shifts over the coming decades.
Safety and noise, once the Achilles’ heels of unducted concepts, are being addressed through extensive testing and modern computing power. Advanced simulations and hundreds of hours of wind tunnel runs have helped engineers fine tune blade spacing and tip speeds to reduce tonal noise. Parallel campaigns on bird strike and debris ingestion have pushed composite blade designs to failure in controlled conditions to validate containment and structural margins. For Lufthansa, Air France, and Singapore Airlines, the emerging data package from these efforts will be crucial. Their regulators and passengers will demand robust proof that an unshrouded fan can operate as safely and quietly as the nacelle wrapped engines that dominate skies today.
Implications for Travelers, Routes, and the In Flight Experience
From a passenger’s perspective, the shift to open fan powered aircraft will be most visible in the silhouette of the plane at the gate. Instead of the familiar large round nacelles under the wings, travelers may see slimmer pylons supporting what look like large sculpted propellers. Seating configurations inside the cabin may also evolve if airframers explore new fuselage cross sections or wing positions to integrate the engine optimally. For example, open fan concepts could pair well with rear mounted configurations or high wing layouts designed to maximize aerodynamic efficiency.
One of the key questions is cabin noise. Early open rotor experiments suffered from pronounced tonal noise that was difficult to insulate against. Today’s designs benefit from more sophisticated blade aerodynamics and acoustic optimization, promising a quieter experience than their predecessors. If engineering targets are met, cabins could actually become more pleasant than on current generation aircraft, especially when combined with the latest advances in vibration isolation and soundproofing. Lufthansa, Air France, and Singapore Airlines, all known for investing in premium cabins, will likely push for configurations that ensure the new technology enhances comfort rather than compromising it.
The performance gains of the RISE engines could also reshape route networks. With a 20 percent improvement in fuel burn on single aisle platforms, airlines gain additional flexibility in how they deploy aircraft on thinner long haul routes or high frequency regional corridors. A medium sized open fan powered jet could make nonstop city pairs profitable that currently require either a very large aircraft or a refueling stop. For global carriers with extensive alliance networks, such as those centered around Frankfurt, Paris Charles de Gaulle, and Singapore Changi, this opens new possibilities for tailoring capacity to demand while shrinking their carbon footprint.
Travelers may not see an immediate reduction in airfares solely because of open fan efficiency, particularly given the significant investment required to develop and certify the technology. However, over the lifecycle of a fleet renewal program, lower fuel consumption translates into more stable operating costs and greater resilience to fuel price spikes. Combined with regulatory pressure to cut emissions and potential incentives for low carbon operations, these savings may help keep air travel accessible even as sustainability requirements tighten.
Airport Operations and Safety in an Open Fan Era
Bringing open fan engines into daily operation is as much an airport challenge as it is an engineering one. Larger exposed blades demand carefully defined safety clearances during taxi, towing, and parking. Ground handling crews must be trained to operate around the new engine disk, and equipment such as belt loaders, catering trucks, and passenger boarding bridges may require modified procedures or even hardware adjustments. The Singapore airport testbed is explicitly intended to map out these practicalities, creating a playbook that can be adopted by hubs in Europe and North America where Lufthansa and Air France operate their largest networks.
Runway and taxiway design will come under scrutiny as well. The aerodynamic behavior of an open fan at low speeds could influence jet blast patterns and crosswind handling characteristics. Airport planners will need to validate that existing pavement strengths, separation distances, and obstacle clearances are sufficient for aircraft equipped with the new engines, or whether enhancements are required. For major hubs already engaged in multi decade expansion programs, aligning future taxiway and stand layouts with the needs of open fan powered jets could avoid costly retrofits later.
From a safety standpoint, regulators are working with manufacturers to ensure that certification frameworks capture the unique features of open fan propulsion. That includes reviewing existing assumptions about fan blade containment, bird strike scenarios, and uncontained failure risks now that the fan operates without a full nacelle. The extensive test work by Safran and GE, including ingestion testing and dedicated blade integrity programs, is aimed at proving that modern materials and design can achieve or exceed the safety record of current engines.
The involvement of Lufthansa, Air France, and Singapore Airlines in these discussions will ensure that the resulting rules are not only technically robust but also operationally practical. As frontline operators, they will be among the first to translate theoretical safety margins into day to day checklists, training manuals, and emergency procedures that protect crews and passengers while enabling efficient use of the new technology.
Positioning for a Net Zero Future
For aviation to meet its net zero commitments by mid century, no single technology will be sufficient. Sustainable aviation fuels, improved air traffic management, lighter airframes, and eventually hydrogen and electric propulsion all have roles to play. Open fan engines sit at the heart of this mosaic as a near to medium term lever for cutting emissions on the high volume routes that define global connectivity. By independent estimates, combining RISE class efficiency gains with high blends of sustainable aviation fuel could reduce lifecycle emissions from a flight by up to 80 percent compared with today’s baseline.
Lufthansa, Air France, and Singapore Airlines have each published their own decarbonization roadmaps, which rely heavily on fleet renewal and fuel switching. The decision to align closely with CFM’s open fan strategy signals that they view advanced propulsion not just as an engineering curiosity but as a core enabler of their environmental pledges. Early engagement gives them better visibility into when and how next generation aircraft might enter their fleets, allowing them to synchronize retirement schedules, training programs, and fuel procurement strategies accordingly.
There is also a competitive angle. Airlines that can offer demonstrably lower carbon flights on key trunk routes may benefit from corporate travel contracts increasingly tied to emissions metrics, as well as from travelers who factor sustainability into their booking decisions. An aircraft powered by a visibly different, cutting edge engine sends a strong message at the gate. For brands that emphasize innovation and environmental responsibility, being among the first to operate open fan equipped jets could become a powerful differentiator.
Crucially, however, the partnership with CFM and Airbus is not exclusive. The airlines are likely to keep an open dialogue with other engine makers and airframers exploring ultra high bypass turbofans, hybrid electric concepts, and hydrogen propulsion. The open fan engines emerging from the RISE program will enter a competitive landscape. Their success will depend on how well they balance performance, cost, and compatibility with whatever energy mix ultimately powers aviation’s net zero future.
What Comes Next for Open Fan Technology and Global Travelers
In the near term, travelers will see the story play out mostly in news from air shows, regulatory summits, and airport announcements rather than on their boarding passes. Wind tunnel campaigns will give way to flight tests on the Airbus A380 flying laboratory toward the end of the decade, while the Singapore airport testbed ramps up to map out operational realities. Lufthansa, Air France, and Singapore Airlines will refine their own internal plans, aligning fleet strategies, training needs, and sustainability reporting with the milestones of the RISE program.
As those technical and operational pieces fall into place, attention will shift to commercial launch decisions. Airframers will need to determine whether to base their next generation single aisle families around open fan propulsion, ultra high bypass turbofans, or a mix of both. Airlines will weigh the benefits of early adoption against the financial and technical risks that accompany any first of type technology. Regulators will finalize the certification frameworks that translate laboratory performance into real world confidence for crews and passengers.
For global travelers looking ahead to the 2030s, the convergence of these efforts suggests a future in which flying medium haul routes could involve boarding aircraft that look and sound noticeably different but deliver a significantly reduced climate impact. Cabins may be quieter, fuel burn lower, and route maps more finely tuned to demand thanks to improved efficiency. The partnership of Lufthansa, Air France, and Singapore Airlines with CFM on open fan engines is one of the clearest signs yet that this future is not just theoretical. It is actively being designed, tested, and refined today.
As the RISE program matures and airports like Changi become proving grounds for new propulsion systems, the once radical idea of exposed composite blades driving large jets may become an everyday sight on ramps from Europe to Asia. For an industry under intense pressure to transform without sacrificing mobility, the arrival of open fan technology marks a pivotal moment. The future of aviation is taking shape in test cells, wind tunnels, and now on the operational front lines, and travelers will be among the ultimate beneficiaries of this far reaching collaboration.