Analysis: Japan crash marks test of how new carbon jets cope in a disaster

ASIANA AIRLINES

04/01/2024 14:08

By Valerie Insinna and Joanna Plucinska
       WASHINGTON/LONDON, Jan 4 (Reuters) - Tuesday's runway
collision in Japan marks the first time a modern lightweight
airliner has burnt down and is being seen as a test case for how
well a new generation of carbon-composite airplanes copes with a
catastrophic fire. 
    The Japan Airlines (JAL) Airbus A350 crashed into a De
Havilland Dash-8 coast guard turboprop plane shortly after
landing at Haneda airport in Tokyo, bursting in to flames. All
379 people aboard the A350 were evacuated from the burning
aircraft, but five of the six coast guard crew were killed. 
    Photographs of the wreckage showed the A350 fuselage in
cinders. While investigators seek the cause of the collision,
the aviation industry is keen to confirm the survivability of
high-tech composite airliners which have transformed the
economics of long-haul flight and airlines in the past decade.
    The crash "is really the first case study that we have, not
only from a fire perspective, but also just from a crash
survivability perspective," said Anthony Brickhouse, an air
safety expert at Embry-Riddle Aeronautical University.
    Both Boeing  BA.N , with the 787 Dreamliner, and Airbus
 AIR.PA , with the A350, made big bets in the early 2000s that
lightweight carbon composites would produce major fuel savings
and be less susceptible to fatigue, reducing maintenance. 
    Shortly after being put into service, the Dreamliner
contended with battery problems that led to fires, resulting in
its brief grounding in early 2013. A later fire on an Ethiopian
Airlines 787 in July 2013 was caused by a short circuit in the
jet's emergency locator transmitter and led to fuselage repairs.
    None of these incidents resulted in hull losses, however.
    The A350 contains 53% composite materials by weight, with
composites making up most of its external structure, including
its fuselage, major portions of its tail and wings, and part of
the nose section.
    Experts said the fact that all passengers and crew evacuated
safely while the structure was intact will renew confidence in
the materials which were certified with special conditions.
    But they cautioned it is too early to draw full conclusions
about how the A350's composite hull held up against fire or what
technological lessons may be learned.
    Comparing the A350 crash to a 2013 crash involving a Boeing
777 operated by Asiana Airlines - which caught fire after it
struck a sea wall, killing three passengers - could provide
engineers with valuable insights into the differences between
composite and aluminum planes during a fire, Brickhouse said.
    The JAL  9201.T  A350 is the first commercial airliner built
mainly of composites to be destroyed by fire but not the first
transport aircraft, though it is unclear what lessons about
composite fires will be available to Japanese investigators.
    In 2015, an Airbus A400M military airlifter - which also
relies heavily on composites - plowed into a field outside
Seville, Spain, after wrongly installed software jammed its
engines. But an investigation into the crash by Spanish military
investigators was kept confidential.
    The accident, which resulted in a high-speed impact and
fire, killed all four flight test crew and left hardly any
visible trace of the plane in the blackened earth.
        
    HOW COMPOSITES WORK
    Composite airframes have several advantages over aluminum
planes, said Bjorn Fehrm, a composites expert at trade
publication Leeham News. 
    While aluminum has a melting point of about 600 degrees
Celsius (1,100 degrees Fahrenheit) and conducts heat, carbon
fiber can withstand temperatures about six times that, with the
structure smoldering and burning away instead of melting, he
said.
    Airbus, in a 2019 guide for firefighters, said the A350
demonstrated "an equivalent level of safety" compared to
traditional aluminum planes, with tests showing an "increased
resistance" to fire penetration. 
    But when exposed to intense heat for long periods of time,
Airbus noted that composite airframes can lose their structural
integrity even if the composite skin appears to be intact.
    In particular, the resin will burn off first and flames will
propagate more slowly while the fire is ongoing, according to a
United States Federal Aviation Administration document. 
    The JAL A350 burned for more than six hours before
firefighters were able to completely extinguish the flames,
broadcaster TBS reported, citing the fire department. 
    That raises a question about whether firefighters need
additional training for handling fires involving composite jets.
    Photos of the accident showed firefighters wearing surgical
masks and helmets but no other protective clothing. 
    "The fire brigades of the airports actually have to look at
why couldn't they stop the fire," Fehrm said.
    Airbus noted earlier tests have shown composites offer
similar fire-resistance to aluminum, with a spokesperson adding
that it had carried out a full evacuation test of the an Airbus
A350-1000 in 2018 with authorities present. 
    Various factors can impact how flammable composites are,
including the structure, fiber materials and layers of
fire-blockers used, said Nabil Al Kabir, a sales manager at
German fire safety solutions firm svt Products GmbH.
    "One point can be taken for sure, if the heat generated from
burning kerosene is that intense, aluminum would also fail."

 (Additional reporting by Lisa Barrington in Seoul, Allison
Lampert in Montreal, Tim Hepher in Paris
Editing by Mark Potter)
 ((Valerie.Insinna@thomsonreuters.com;))