Unlock the Editor’s Digest for free
Roula Khalaf, Editor of the FT, selects her favourite stories in this weekly newsletter.
The wreckage of the Japan Airlines plane at Tokyo’s Haneda airport is testimony to the fierceness of the blaze that consumed it on Monday evening after it collided with a smaller plane.
For investigators and aviation experts, the episode — and how all 379 people onboard the JAL flight managed to escape — is likely to yield important insights into the modern materials used to build many aircraft and the best ways of safely evacuating passengers in emergencies.
The crash was the first loss of an Airbus A350, a model that entered service in 2015, and first complete destruction by fire of an airliner made largely from carbon fibre, a material increasingly used in aerospace.
“The JAL A350 is the first hull loss of a composite airliner and the first by fire,” noted Scott Hamilton, head of consultancy and news site Leeham News. “Investigators will learn all kinds of lessons from the A350 accident.”
Five of the six people onboard a smaller De Havilland Dash-8 Japan Coast Guard aircraft that collided with the JAL plane died.
While the cause of the accident and the exact sequence of events remains under investigation by the Japan Transport Safety Board, police and other official agencies, experts said the evacuation of the 367 passengers and 12 crew from the JAL plane was remarkable.
Early indications suggest the intercom system between the flight deck and the cabin had broken down following the collision while only three of the eight exit doors were available for evacuation given the fire on the outside of the aircraft.
“It was a good outcome but the evacuation scenario was high risk,” said Ed Galea, a professor at the University of Greenwich in London, who specialises in fire safety. He noted that the nose was also angled downwards, making it harder to use the inflatable slides.
“In these circumstances, every second counts.”
Modern aircraft are required to prove to regulators that they can evacuate all passengers and crew within 90 seconds using half the number of the available exits. Aircraft cabins are designed to prevent flames from spreading for as long as possible.
“The most important part, whether the plane is aluminium or carbon fibre, is that you have protection for many, many minutes from external heat,” said Bjorn Fehrm, an aeronautical engineer and an analyst at Leeham News. “In this case, the carbon fibre is giving that heat-shield protection.”
Airbus said that composite materials made up 53 per cent of the model in question, the A350-900. The plane maker said tests had shown that composite structures offered a similar level of fire resistance as aluminium, typically used in older aircraft.
While composite materials are not new to the aerospace industry, their use has increased significantly in recent years as both Airbus and Boeing have focused on reducing weight and increasing fuel efficiency.
Leeham’s Hamilton pointed out that fires have previously occurred on two Boeing 787s with similar amounts of composite materials.
In January 2013, a battery overheated and started a fire in a JAL aircraft parked at Boston airport after a flight from Tokyo. In July of the same year, an Ethiopian 787 parked in London suffered fire damage caused by a short circuit at the emergency locator transmitter. Both planes were heavily damaged but repaired.
Aviation experts said the images of the burning JAL A350 showed that the composite structure appeared to withstand the heat for a long time.
Aluminium melts at about 600 degrees Celsius and, although composites would burn at a lower temperature, they reacted differently to fire, said Emile Greenhalgh, professor of composite materials at Imperial College in London.
“As the material burns, all the flammable material forms a char layer . . .[so] you end up with a barrier against the progression of fire.”
The accounts from both crew and passengers on how they pulled off the evacuation in such demanding circumstances should also provide lessons on best practice and safety at airports, experts said.
Although everyone on the JAL plane survived, Galea at the University of Greenwich questioned the efficacy of the 90-second evacuation tests because they often bore little resemblance to real-life accidents. “I call it a benchmark as it says nothing of the performance of the aircraft in the event of an accident.”
Read the full article here
