Recaro's titanium-aluminum-carbon fiber reinforced plastic seats (Photo courtesy of Recaro)

The airline industry continues to look hard at plastic composites and other new materials as it faces increasing pressure to reduce fuel consumption and cut the environmental impact from flying, according to several aviation industry executives interviewed at the Asian Aerospace International Expo and Congress, held Sept. 8-10 in Hong Kong.

But, they said, plastics must improve performance to meet stringent tests that require things like withstanding crash forces of 16 times gravity.

“There is a huge potential, even in the structural components, for new materials from metallics … and reinforced carbon fiber plastic materials,” said Axel Kahsnitz, CEO of Recaro Aircraft Seating in Schwaebisch Hall, Germany. “There are a number of new materials which give us the opportunity to reduce the weight and keep the comfort in the seat.”

Recaro, one of the world’s leading seat makers, earlier this year unveiled a super-lightweight seat made with titanium and carbon fiber reinforced plastics. But Kahsnitz said the company has learned there are limits with today’s technology in using carbon-fiber plastics in structural components, and said manufacturing processes need to be improved.

“Boeing learned the same lesson in their 787,” he said, referring to the company’s well-publicized problems with plastic composites. The 787 Dreamliner will be the first plane built with body and wings made substantially from composite plastics.

Other aircraft makers, like Canada’s Bombardier Inc., are significantly boosting use of metal and plastic composites in structural parts of new planes.

Recaro, though, has since turned back to metallics on structural components in seats. After it unveiled its “Stingray” lightweight prototype seat made from titanium, aluminum and carbon fiber reinforced plastic at an air show in Hamburg, Germany, it found that airlines are not interested in paying the higher costs for that seat, he said.

Nonetheless, he said the company continues to do research with universities on other applications for plastic composites, and he said composites could provide opportunities for low-wage countries like China because they are labor-intensive to manufacture.

He told a forum at the Asian Aerospace show that the airline industry needs to work with regulators like the Federal Aviation Administration in the United States to get these new materials qualified for use.

An executive with the European aerospace conglomerate Airbus said the industry is under constant pressure to reduce weight, and he suggested it may be reaching the limits of weight reduction for some traditional metals in passenger cabins.

That creates opportunities for plastics and composites, said Jonathan Norris, vice president of cabin design with Airbus’s office in Hamburg, Germany.

But he said the aviation industry is also somewhat skeptical of composites in structural applications in seating because the manufacturing process is not as standard and predictable as it should be, leading to problems with safety performance.

Those tests “are very, very difficult for a seat component that is made of non-metallics,” Norris said.

More work is needed on potential replacement materials, he said.

“We need to be looking at other materials to say how do we keep the weight out and keep the costs on a par or marginally increase it,” Norris said. “We’re not hitting that point at the moment. … This is the real challenge. This is why I think there is more that needs to be done with plastics and composites.”

A typical airline seat weighs between 12-25 kilograms but he said Airbus has a challenge out to its supply chain to get that weight under 10 kilograms.

Some, like Recaro, have tried to answer that. Its Stingray seat unveiled in March weighs about six kilograms, but Norris said it’s too expensive.

“No airline is going to pay for a titanium seat,” he said. “How do we move things on in the mix so we get the weight out at a sensible cost?”

Problems with seat weight don’t rest entirely with materials, though.

Like a recalcitrant dieter, the airline industry has actually added weight, even as it has tried to shed pounds.

Speakers at the Asian Aerospace forum said airlines have made seats up to 10 kilograms heavier since the mid-1980s, as they’ve added video screens and other features to increase passenger comfort and generate sales.

But rising fuel costs and environmental pressures are causing a rethink, according to Vernon Alg, a consultant on aviation industry cabin design and 40-plus year engineering veteran of American carrier Continental Airlines.

“There were a large number of projects that didn’t get off the ground until fuel costs rose above $60 a barrel,” he said in an interview at the Aerospace show. “Weight today is critical…You have a lot of opportunities for plastic to replace metal.”

While there are certification issues, plastic should be used more in non-structural applications like galleys panels, armrests and footrests, he said. Small reductions per seat can get enough savings over the whole plane to add another passenger, half a dozen bags or more fuel, he said.

“Every ounce is important — it wasn’t when fuel was $20 a barrel,” he said.