OEMs, System Manufacturers Find New Leads To More Enjoyable Cabins

Dassault Aviation's new Falcon 10X features a large kitchen designed for the ultra-long-range aircraft.
Credit: Dassault Aviation

New technologies and continuing progress in system engineering are improving the passenger’s experience in a business aircraft cabin.

These techniques are not just enabling nice-to-have features. They are driving comfort enhancements that help the passenger arrive in a good form, ready for a meeting. After all, the continuity of the customer’s activities is what business aviation is all about.

Some of the advances are visible, such as in the galley area, where the setting is increasingly being designed to make the occupant feel at home.Some are hardly noticeable. The designers of air management, lighting and cabin window systems endeavor to counter travel fatigue. They simultaneously are contributing to greater efficiency in today’s aircraft.

“Customer expectation trends in the cabin are a reflection of many larger trends happening on the ground: a focus on personal wellness, a welcoming feeling to the entire cabin, including crew areas like the galley, and a flexibility to adapt spaces to casual socialization or to privacy as the need arises,” says Nathan Kwok, Safran Cabin’s vice president, marketing.

In line with a trend to have the cabin resembling a luxurious apartment, the galley tends to look like a high-end kitchen. In other words, the galley should no longer be designed as if it was reserved for flight attendants. This is reflected in refined lines and sophisticated, integrated pieces of equipment. Greater aircraft ranges and the resulting longer flights also call for a larger space to prepare meals.

At the same time, passengers request a greater variety of services. To cope with the requirement for a more elegant look, multifunction machines are being offered. “We see demand for an insert that makes various sorts of coffee – from espresso to cappuccino – and tea, as well as a dual conventional microwave oven,” says Julie Imbert, Safran Cabin’s marketing director.

In the future, Safran expects to offer products with a smaller environmental footprint. Imbert is not specifying how they will be made more sustainable but she intends to anticipate customer demand.

To fight the tiredness one experiences when on a long journey, the altitude felt in the cabin has to be lower than the aircraft’s actual altitude. Hence the need for pressurization. And the trend toward lower cabin altitudes tends to accelerate. On the new Falcon 10X, Dassault is promising a cabin altitude of 3,000 ft (down from the Falcon 7X’s 3,950 ft) at 41,000 ft above sea level. Moreover, as the air tends to be dryer as the aircraft’s altitude increases, passengers may experience throat irritation, dry eyes and overall fatigue on long flights. Hence the need for a humidification system.

Passenger comfort is the main design driver. Nevertheless, the system should be designed so that the weight of the water it carries is kept to a minimum, while the cabin and internal fuselage remain free of condensation.

In business aviation, weight is a little less of a constraint than it is in commercial aviation, thanks to the smaller number of passengers, Nicolas Bonleux, Liebherr Aerospace’s managing director and chief commercial officer, explains. Humidification systems are benefitting from improved efficiency and precision, he adds.

Most systems use an electric heating process to vaporize water. Liebherr’s system uses bleed air to bring water to boiling temperature. Bleed air – hot, high-pressure air from inside the engine – is primarily used for cabin pressurization and wing anti-icing. Enough heat remains available for water-boiling purposes. Liebherr thus claims its system is more efficient, as it uses energy that would otherwise be wasted.

“Moreover, we can tune the system according to the number of passengers in the business jet’s cabin,” says Bonleux. Liebherr supplies air management systems (or environmental control systems, ECS) for Bombardier’s Global and Challenger families, as well as Dassault’s Falcons. “We see a general demand in aviation, and even more in high-end business aviation, for greater air quality,” Bonleux emphasizes.

In filtration, the ongoing health crisis has prompted a renewed research effort for a built-in treatment that would stop smaller bacteria. The outcome is several years off. Nevertheless, the way cabin air is renewed already makes an aircraft cabin a particularly pure, particle-free environment, Bonleux notes.

As the ozone content of high-altitude air is greater, certification standards require a chemical conversion process to cap it to ground level. The system is called an ozone converter and comes in addition to other components of the ECS. Liebherr is studying how to combine several functions, such as filtration and ozone conversion, into one system. The idea is to reduce weight and improve efficiency.

At the same time, pneumatic valves are being progressively replaced with electric ones. Regulation can be fine-tuned, thus enabling a reduction in power consumption and the design of a smaller valve. And the move to composite materials, from metallic alloys, is allowing further weight savings.

Moreover, electric valves include redundancies that translate into a cut in the part count.
Business aircraft are sometimes used in a “lounge” mode on the apron. Some airports, however, forbid the use of current auxiliary power units (APU) because of the noise and local air pollution they generate.

Liebherr is working on a hydrogen-powered APU that would solve the problem. The technology readiness level is still relatively low. Even so, Liebherr engineers hope such an APU would, in addition to direct environmental progress, be able to run during the entire flight and not just on the ground. The engines would no longer have to supply electricity, their design thus being focused on propulsion. Overall aircraft efficiency would be enhanced.

Over recent years, LED lighting has opened a field of possibilities for cabin interior designers. Companies like Aveo Engineering, formed in 2006 thanks to the advent of the technology, are active in answering requests for standard lighting replacement. LED lighting offers unlimited choice in color and mood creation. Colors are warmer. As they are smaller than conventional bulbs, LEDs enable a better focus.

LED lights are more expensive to acquire but they are much more durable, reliable and efficient. Ultra-thin LED foils are not suitable for illumination but can be used to color a surface. More generally, accent lighting – such as underlining a contour – and projections – such as the company logo or destination – offers new options for a cabin’s appeal.

“LEDs contribute to improving passenger comfort, especially on long flights,” says Franck Burnet, a consultant in cabin interiors and a veteran in the business aviation industry. “Mood lighting, such as a sunrise atmosphere, helps the body adjust. Feeling relaxed is all the more challenging as the flight is long. And it is all the more important as the passenger may want to attend a meeting shortly after landing.”

Light could help cabin hygiene, too. Aveo is promoting the use of visible violet and ultraviolet (UV) light for disinfection purposes.

“The 405 nanometer light is the disinfecting component of the sunlight. A violet light can run all the time and be masked by normal white light. We use these lights to keep galleys and lavatories clean,” says Georg Hartl, Aveo’s quality and certification administrator.
Then, UV-C light (at 275 nanometers of wavelength) is for intense disinfection but humans need to be protected. It can be used for disinfection between flights.

UV-C lighting can be installed in the cabin, as opposed to carried on a special device by a technician. Cabin installation means an operator could use them even though the aircraft is waiting at a little equipped airport. A limitation is a need, for a surface to be disinfected, to be directly within sight of the light source.

“Both violet and UV-C light are known for being effective against bacteria, viruses and fungi,” says Hartl.

Another way to improve comfort lies at the window level. Dimmable windows, which provide tint-tuning up to an instant almost complete black-out, have been gradually gaining ground. Vision Systems is a specialist in such smart windows and its products can now be found on four business aircraft, notably the Embraer Phenom 300 and the Falcon 6X. The company is working on integrating them onto another four, says Nicolas Laurent, sales director.

“You keep both the shade effect and the vision of the aircraft’s environment,” says Laurent. Acting as a touchscreen, the window itself incorporates the controls. A recent feature has been the ability, for the passenger, to dim the window in separate horizontal bands, from the top to the bottom of the window.

As an integral part of the cabin management system, dimmable windows can work in conjunction with mood lighting.

Vision Systems supplies integrated casings that, depending on the customer’s choice, may include the dimmable window, a conventional shade or both. Conventional shades provide complete blackout, which some passengers prefer for a sleep-conducive atmosphere. They also can be part of a more cocooning ambiance, with the entire interior in the same color tone when the shades are lowered.

Thierry Dubois

Thierry Dubois has specialized in aerospace journalism since 1997. An engineer in fluid dynamics from Toulouse-based Enseeiht, he covers the French commercial aviation, defense and space industries. His expertise extends to all things technology in Europe. Thierry is also the editor-in-chief of Aviation Week’s ShowNews.