by: Adam Dodson

aviation fire investigationThis past summer I had the good fortune of being able to intern at Boeing Commercial Aircraft in Seattle, Washington. In addition to falling in love with the Pacific Northwest and landing a full time job as a MP&P Flammability Engineer after graduation, I was able to learn much about past aviation fire incidents. More specifically, I learned about how these accidents shaped the current state of aviation fire safety.

On July 17th 1996, a Boeing 747-131 Trans World Airlines flight 800 crashed into the Atlantic Ocean off the coast of New York. All 230 people on board were killed in the crash. There was an explosion in the plane’s center wing fuel tank, which caused an in-flight break up of the plane. The energy that caused the ignition of the fuel was determined to most likely have come from a short circuit in the wiring in the fuel quantity indication system. The center wing fuel tank was expected to have flammable liquid inside, but it was also expected to have no ignition sources. As a result of this accident, the FAA imposed additional regulations on fuel tanks. This included a requirement for inert gas systems in fuel tanks to reduce the flammability of possible fuel vapor/oxygen mixtures. Injecting inert gases such as Argon into fuel tanks was shown to reduce the flammability of the vapor mixtures.

On June 2nd 1983, a McDonnell Douglas DC-9-32 Air Canada flight 797 experienced a lavatory fire while on its way from Dallas to Toronto. The lavatory circuit breakers had tripped, but were reset by the pilot, who thought nothing of it because this happened from time to time and was not considered an emergency. This resulted in an electrical fire breaking out near the lavatory. The flight crew attempted to flood the lavatory with a carbon dioxide extinguisher and thought the fire may have even been put out due to the lack of flames. The fire, however, was not extinguished and continued to grow and breach into the cabin. The plane made an emergency landing, but reached flashover conditions less than 90 seconds after the start of the evacuation. It is likely that incoming oxygen from opening the doors for escape helped the fire grow exponentially. 23 of the 41 passengers died from smoke inhalation and burns from the fire. Notable recommendations to the National Transportation Safety Board after the incident included expediting actions to require smoke detectors in lavatories, using advanced suppression agents such as Halon, emergency track lighting to the exits, and changing crew procedures to more aggressively pursue potential fires.

On August 19th 1980, a Lockheed L-1011-200 Tristar experienced a cargo fire shortly after takeoff from an unidentified source. It took the passengers who smelled smoke four minutes to warn the crew and pilot who then turned the plane around for an emergency landing. Emergency personnel did not board the aircraft for 23 minutes after the engines had been shut down because they had a difficult time getting the doors open. When emergency services did open the doors, they found that everyone on board had died of toxic smoke inhalation. It was assumed that most passengers were incapacitated on landing as all the main cabin doors were still shut and the aircraft was still pressurized. As a way to increase the time between flame ignition and evacuation of the airplane, new flammability tests were required as a result of this accident. The Oil Burner test, which tests flame and heat penetration through the cargo liner walls, is one such flammability test.

Finally, On May 11th 1996, a ValuJet Airlines DC-9-32 crashed into the everglades after departing from Miami airport. There was a fire that originated from an improperly contained chemical oxygen generator. This was stored in a class D cargo compartment that was not required to have fire detection or suppression. Rather, it relied on flame resistant materials and being airtight to minimize risk. Unfortunately, the chemical reaction in the oxygen generators was exothermic, meaning it produced oxygen and heat, which was enough to cause a fire that could burn through into other compartments. The fire grew and disabled the control cables in the back of the aircraft, giving the pilots no control. All 210 people on board died in the ensuing crash. Swampy conditions made it difficult for rescuers and the clean up crew to enter the area because of the water and threats like crocodiles and disease. This accident led to increased FAA regulations that required all class D cargo compartments to be upgraded to class C, meaning they were required to have fire detection and suppression systems installed, ventilation control, and a means to exclude smoke, flames, and extinguishing agent from crew areas.

As tragic as these events are, they allowed aircraft manufactures the opportunity to learn how to make aircraft more fire safe. Significant progress has been made in making aircraft more adequately protected from fire, which continues to this day. I am excited to be working toward continuing this trend when I graduate and get the opportunity to use my fire protection engineering degree to make aircraft even more fire safe.

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Comments
  1. Glad you enjoyed Boeing. I worked there as a fire protection engineer between 1979 and 1987, mainly supporting facilities organizations. During those days, they did not consider using the expertise of fire protection engineers for their products, but left it up to the FAA to dictate requirements. Glad to hear that someone in a fire protection engineering capacity is getting involved with the aviation portion of the business.

    Like

  2. It is excellent to see young individuals take an interest in failure analysis. It’s these new individuals who are aware of past destruction what will come up with new ideas to improve our safety. A a failure analysis expert and college instructor, I am looking forward to this new and upcoming talent. Good luck with your endeavors.

    Like

  3. Brian Jeeff says:

    Hi,
    This post is really so informative & containing the dates on which plane crash has occurred on fire. A plane or fire is really so dangerous & very horrible. I had recently heard from somewhere that one of the agency from the US working for Aircraft fire protection & purchasing damaged fire extinguisher from the public. I think they are doing good.

    Like

  4. Brian Jeeff says:

    Hi,
    This post is really so informative & containing the dates on which plane crash has occurred on fire. A plane or fire is really so dangerous & very horrible. I had recently heard from somewhere that one of the agency named Halon.Us from the USA working for Aircraft fire protection & purchasing damaged fire extinguisher from the public. I think they are doing good.

    Like

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