The Japan Airlines plane that caught fire used carbon-fiber composite materials that are less heat-resistant

• The Airbus A350 that caught fire in Tokyo used carbon-fiber composites that are less heat-resistant than metal.
• The accident on Tuesday is likely to be seen as a test case for the lightweight materials' use in aviation.

The fuselage and wings of the crashed Japan Airlines Airbus A350 were made using a carbon-composite material that's likely to receive renewed attention in the aftermath of Tuesday's fiery accident.

Experts have remarked on the material of the plane's construction in discussing the spread of the fire — but have not so far suggested it worsened the disaster.

In the accident, the landing Japan Airlines plane hit a Japanese Coast Guard aircraft that was on the same runway at Tokyo's Haneda Airport.

Video showed a massive fire burning as it headed down the runway and came to a stop.

Remarkably, all 379 people on board the A350 survived despite flames engulfing the aircraft. Five of the six people on the smaller Coast Guard aircraft were killed. The exact circumstances of the accident are still unknown.

In a statement on Tuesday, Airbus said it was sending a team of specialists to help Japanese authorities to help investigate the accident. The A350's use of carbon-fiber materials may well be one of the factors discussed in the probe.

Passenger airliners have conventionally been built primarily from metals like aluminum, steel and titanium.

But engineers have increased the proportion of more lightweight — and thus more fuel-efficient — carbon composite materials, Dr Sonya Brown, a senior lecturer in aerospace design at the University of New South Wales told The Guardian.

Those used in the Airbus A350's wing and fuselage are known as carbon fiber reinforced polymers, or CFRPs, per The Guardian.

Industry new site Simple Flying last year called the material's light weight a "game changer" for the Airbus A350. It's also used in the Boeing 787.

Airbus says that the A350's airframe uses composites, alongside titanium and aluminum alloys, "to create a lighter and more cost-efficient aircraft, while increasing resistance to corrosion and reducing maintenance."

The company also says that the carbon-fiber skin "is more 'burn through' resistant than a metallic equivalent."

In Tuesday's accident, the material quickly caught attention from expert onlookers, with former CNN Aviation Editor Jon Ostrower remarking on X: "This is really something."

Safety consultant Jon Cox told the Associated Press that "this is the most catastrophic composite-airplane fire that I can think of."

He added: "On the other hand, that fuselage protected [passengers] from a really horrific fire — it did not burn through for some period of time and let everybody get out."

Brown, speaking to The Guardian, agreed that the materials used would impact the fire performance of the craft. "While we don't know the specifics of the resins used in the plane in this incident, they will lose their structural capability, their sense of thickness, at a lower temperature than aluminum," she said.

But she said that while the carbon-fiber composites "will change the performance of the fire," they "weren't going to change the overall outcome of this."

"Carbon fiber composites might start to lose some of their stiffness at about 200 degrees, while aluminum will melt at about 700 degrees," she said.

"But the fire we saw on that fuselage will have had temperatures above 1000 degrees Celsius," Brown continued — making the difference relatively insignificant.

She said the plane's wing construction likely contained firewalls — sections of material that are less easily combustible — that will have slowed the blaze's progress.

The aircraft will also have used much of its fuel before it landed, reducing the risk of an explosion, she said.

Graham Braithwaite, an expert on flight safety at Cranfield University in the UK, told Business Insider's Tom Porter that strong crew training and other aspects of the aircraft's design likely helped the passengers evacuate safely, even as the fuselage burned.

"This is an example of a plane evacuation gone well," he said.

He also pointed to the design of the A350 cabin, which has well-marked exits and uses fire-resistant materials where possible. The resulting evacuation "also speaks to the durability of modern aircraft, and how well designed they are," he said.