Is it Combustible Carbon Fiber? Understanding the A350's Unstoppable Consummation in JAL 516 Incident

The Accident?

On January 2nd, 2024, at Tokyo Haneda Airport, a Japan Airlines Airbus A350-900 (registration JA13XJ) operating as flight JL-516 from Sapporo, carrying 367 passengers and 12 crew members, collided with a Japanese Coast Guard Dash 8-300 (registration JA722A) shortly after landing on runway 34R at 17:47 local time. The collision led to a fire engulfing both aircraft. The A350 came to a stop off the right-hand edge of the runway after traveling about 1680 meters (5510 feet) and was successfully evacuated, with all occupants safely leaving the aircraft. However, the Coast Guard aircraft, carrying 6 people, resulted in 5 confirmed fatalities and one individual receiving serious injuries.

During the landing, passengers initially perceived a normal touchdown, but soon after, a collision occurred, illuminating the surroundings in orange light. Although there was no explicit instruction to evacuate, when some passengers stood up, others followed suit, enabling their escape.

The airline confirmed all occupants were evacuated without anomalies reported before the flight. Initial investigations by the Japan Transport Safety Board (JTSB) indicated that the A350 had received landing clearance. However, details surrounding the collision, such as the clearance of the Coast Guard aircraft and the sequence of events leading to the incident, remain under investigation by both the JTSB and other international investigative bodies, including the French Bureau of Enquiry and Analysis for Civil Aviation Safety (BEA) and the Air Accidents Investigation Branch - UK (AAIB) .

Additionally, there have been reports suggesting a discrepancy in radio frequencies used by the aircraft and the tower. Tokyo's Metropolitan Police and the Ministry of Transport are looking into the ATC communication and the awareness of the tower controller regarding the presence of the Coast Guard aircraft on the runway.

As investigations continue, Haneda Airport partially resumed operations after several hours, redirecting incoming flights to Narita Airport. However, the exact timeline for full airport operation remains uncertain.

The Ministry of Transport revealed that the Coast Guard DH8C may have misunderstood instructions, leading to its positioning on the runway, while the A350 pilots were not aware of its presence. The JTSB recovered one of the DH8C's black boxes and is in the process of retrieving the A350's flight data recorders.

Amidst ongoing inquiries, the details surrounding the cause and sequence of events leading to the collision and subsequent fire continue to unfold. The Ministry of Transport, law enforcement, and aviation authorities are diligently investigating the incident to determine accountability and prevent future occurrences.

Understanding the Airbus A350 and Carbon Fiber

Airbus A350 XWB Construction

The aircraft's structure comprises a blend of materials, featuring 45% lightweight, high-strength composite construction, including carbon fabric laminates supplied by TenCate Cetex selected by Airbus in November 2010, and 55% comprised of low-density aluminum-lithium alloy, steel, aluminum, and titanium components. Magellan Aerospace Limited received a contract from Airbus in February 2011 to deliver intricate machined aluminum lithium detail components.

Its wings, with a wingspan of 64.8 meters and a sweep of 35°, are constructed using a metal-ribbed, three-spar design made of carbon-fiber-reinforced plastic (CFRP). Atkins was commissioned in June 2009 to supply composite wing flaps, aiming to reduce overall weight and carbon emissions.

The A350 XWB employs a fly-by-wire system akin to other aircraft families like the A320, A340, and A380. This system ensures handling and flight deck commonality, facilitating cross-crew qualification and mixed-fleet flying. Primary flight control actuators from Moog and a Rockwell Collins horizontal stabilizer activator are installed in the aircraft.

Various subcontractors, including Hexcel Corporation for carbon-fibre composites, Spirit AeroSystems for the upper fuselage, GKN Aerospace for the fixed trailing edge, and Latecoeure, contribute to different sections of the aircraft.

Airbus contracted CAE in September 2010 to design and develop full flight simulators (FFS) for both the Airbus A350 XWB and Boeing 777 aircraft. CAE created two CAE 7000 series FFS for the A350 XWB and six CAE Simfinity A350 XWB Airbus process trainers, with the initial FFS delivered to Airbus in 2012.

Notable manufacturing milestones included the delivery of the first Airbus XWB center wing box and keel beam to Airbus' St Nazaire facility in August 2011, signifying a pivotal step in the aircraft's final assembly. Additionally, in September 2011, Airbus received the first A350 XWB wing lower cover at their manufacturing site in Broughton, UK. This wing cover, integrated with the A350 XWB wing, was transported to France for the conclusive phase of assembly.

Advantages and Properties of Carbon Fiber in Aviation

High Strength-to-Weight Ratio

Carbon fiber is exceptionally strong while remaining lightweight. This characteristic is vital in aviation as it allows for the construction of sturdy, durable components without adding excessive weight, contributing to fuel efficiency and increased payload capacity.

Stiffness and Rigidity

Carbon fiber is known for its stiffness and rigidity, providing excellent structural integrity to aircraft components. This property helps in maintaining the structural shape and integrity even under high-stress conditions such as during turbulence or maneuvers.

Fatigue Resistance

It exhibits remarkable fatigue resistance, meaning it can withstand repetitive stress and load cycles without weakening. This attribute is crucial for aircraft components subjected to constant pressure and vibrations during flight.

Corrosion Resistance

Unlike metals, carbon fiber is highly resistant to corrosion and degradation caused by environmental factors like moisture, chemicals, or temperature changes. This makes it a durable and long-lasting material choice for aircraft parts.

Customizability and Design Flexibility

Carbon fiber's versatility allows for complex and customized designs, enabling engineers to tailor components to specific shapes and sizes while maintaining strength and reducing overall part counts.

Reduced Maintenance

Due to its durability and resistance to corrosion, carbon fiber components often require less maintenance compared to traditional materials, leading to cost savings and increased operational efficiency for airlines.

Improved Fuel Efficiency

Using carbon fiber in aircraft construction contributes to reduced fuel consumption due to the material's lightweight nature, leading to lower operational costs and a smaller environmental footprint.

Noise Reduction

Carbon fiber components can contribute to reducing noise levels inside the aircraft, enhancing passenger comfort during flight.

Role of Composite Material in Damaging Aircraft

In the context of the JAL accident and the subsequent fire outbreak, the utilization of Carbon Fiber Reinforced Polymer (CFRP) in the aircraft's construction could have significantly influenced the swift propagation and challenging extinguishment of the fire.

The characteristic properties of CFRP, designed to enhance the structural integrity and reduce the weight of the aircraft, play a pivotal role in the fire's rapid spread and resistance to extinguishers:

Char Formation

CFRP tends to undergo charring rather than rapid combustion when exposed to fire. This charring forms a protective layer, acting as insulation against further damage. While this insulation can prevent immediate destruction, it also creates a barrier that hinders the penetration of extinguishing agents, making it harder to fully suppress the fire.

Low Thermal Conductivity

One of CFRP's properties is its low thermal conductivity, meaning it doesn't efficiently transfer heat. While this can impede the fire from spreading to adjacent areas, it also poses challenges in cooling down the affected regions. Traditional extinguishing agents might struggle to effectively reduce the temperature within the material due to this low thermal conductivity.

Penetration Challenges

The intricate composition of CFRP, involving multiple layers of carbon fibers embedded within a resin matrix, presents a challenge for conventional extinguishing agents like water or foam. These agents may struggle to penetrate the layers and reach the core of the fire, limiting their effectiveness in suppressing the flames.

Chemical Resistance

Some variations of CFRP materials may exhibit chemical resistance, reducing their susceptibility to certain types of extinguishing agents commonly used in firefighting.

Considering these factors, the use of CFRP in the aircraft's structure could have contributed to the challenges faced by firefighting teams in swiftly containing and extinguishing the fire following the JAL accident. The unique nature of CFRP materials presents hurdles that demand specialized firefighting approaches and techniques to effectively manage and extinguish fires involving such composite structures in aviation incidents.

Further Potential Reasons

Fuel Types and Quantities Onboard

The amount and type of fuel carried by the aircraft could significantly impact the severity and duration of the fire following the collision. Leakage or spillage of aviation fuel due to structural damage during the impact might have exacerbated the fire, posing challenges for firefighters in containing and extinguishing it. The ignition of fuel vapors could have intensified the fire, affecting the overall severity of the situation.

Electrical Systems and Potential Malfunctions

Malfunctions or damage to the electrical systems of the aircraft during the collision could have led to short circuits or sparking, serving as additional ignition sources for the fire. Electrical failures in critical systems might have further complicated the response efforts and firefighting procedures.

Structural Vulnerabilities Beyond Carbon Fiber

While carbon fiber (CFRP) is a significant structural component, other materials used in the construction of the aircraft, such as aluminum, titanium, and steel, could also exhibit vulnerabilities upon impact. Structural damage beyond the CFRP areas might have compromised the integrity of the fuselage or other critical components, contributing to the fire's rapid spread or hindering evacuation efforts.

Proximity and Severity of Impact During the Collision

The nature and severity of the impact between the Japan Airlines Airbus A350 and the Japanese Coast Guard Dash 8-300 could have played a crucial role. The location of the collision on the runway, the speed, angle, and force of impact might have caused substantial structural damage, rupturing fuel lines, damaging electrical systems, and initiating the fire.

Challenges in Fire Suppression and Extinction

The complete destruction of an airliner primarily constructed from carbon fiber marked a groundbreaking event in modern aviation.

It's notable that previous incidents involving Boeing 787s, which contained comparable amounts of composite materials, encountered fires. In January 2013, a JAL aircraft parked at Boston's airport experienced a fire due to a battery overheating after a flight from Tokyo. Similarly, in July of that year, an Ethiopian 787 parked in London suffered fire damage caused by a short circuit at the emergency locator transmitter. Despite heavy damage, both planes underwent repairs.

Aviation experts examining the burning JAL A350 highlighted the composite structure's apparent resilience to heat. Professor Emile Greenhalgh from Imperial College, London, emphasized that while aluminum melts at approximately 600 degrees Celsius, composites burn differently, forming a protective char layer that acts as a barrier against the fire's progression.

According to a 2012 U.S. Air Force Research Laboratory study, composite-skinned airframes burn differently than their aluminum counterparts. The insulating properties of aircraft composite materials resist external heat sources but pose challenges in cooling down once heated, complicating firefighting efforts, especially in areas hidden from firefighters.

Boeing's informal guidance on fighting composite aircraft fires, issued post the 787 introduction, suggests no major protocol changes. The document emphasizes that composite structures, while enhancing strength, act as fire and heat barriers. They don't contribute to fire spreading and, in fire tests, present no greater toxicity hazard than aluminum fuselage aircraft. Additionally, the burn-through time on composite structures is notably longer, potentially offering enhanced safety for responders and passengers in certain scenarios.

Specific safety features, such as firewalls around engines, nitrogen pumps in fuel tanks, and fire-resistant materials on seats and flooring, likely contributed to containing the fire. Dr. Sonya A. Brown from the University of New South Wales highlighted that fire-resistant elements might slow initial fire progression, aiding in safely evacuating passengers.

Regarding firefighting challenges specific to aircraft fires, the six-hour duration of the blaze on the JAL A350 despite evacuating all 367 passengers and 12 crew members highlights the complexity of extinguishing composite-based aircraft fires.

Factors impacting fire suppression efforts could include the inherent resistance and burn characteristics of composite materials, difficulties in accessing hidden fire areas, and the insulation properties that challenge cooling. Despite safety features and enhanced resistance, the prolonged duration of the fire underscores the difficulties in extinguishing fires involving composite structures in aviation incidents.

Losses in Accident and Ongoing Investigations

The incident involving the collision and subsequent fire between a Japan Airlines (JAL) aircraft and a Coast Guard plane at Tokyo's Haneda Airport holds significant implications for aviation safety and ongoing regulatory considerations.

The malfunctioning of the warning lights, essential indicators for pilots regarding runway clearance, on the night of the incident has surfaced in official aviation data. A NOTAM message issued days before the event highlighted the system's outage, raising questions about the impact, if any, of the malfunctioning warning lights on the unfolding incident. However, the conclusive role of the non-functional warning lights in the sequence of events remains part of the ongoing investigation.

The losses incurred from the incident, both in terms of human lives and financial aspects, have been substantial. Japan Airlines anticipates losses exceeding $100 million due to the destruction of the Airbus A350 widebody jet. All 379 individuals on board managed to evacuate before the aircraft was engulfed in flames, which persisted for more than six hours before being extinguished. Tragically, five crew members from the Coast Guard plane lost their lives, while the surviving pilot sustained severe injuries.

The financial impact for JAL, estimated at around 15 billion yen ($105 million), is expected to be covered by insurance. Discussions regarding compensation for affected passengers, including those who lost pets in the incident, are underway. The insurer for the destroyed two-year-old plane is reportedly U.S. insurer AIG, holding a $130 million "all-risks" policy. This incident marks the first-ever hull loss globally for the A350 model since its introduction in 2015, posing financial ramifications for JAL and influencing market sentiments, as evidenced by the fluctuations in JAL's stock prices.

Furthermore, the aftermath of the collision led to a significant disruption in flight operations at Haneda Airport, with numerous cancellations and delays impacting frustrated passengers, while debris from the incident scattered across the runway and ongoing investigations continued.

The incident's ramifications on aviation safety protocols and the comprehensive investigations underway to determine the primary cause(s) will be crucial in reassessing safety measures and regulations to prevent similar occurrences in the future. The collaborative efforts of regulatory bodies, aviation experts, and airlines are pivotal in enhancing safety standards and mitigating potential risks in aviation operations.