This study is based on 1036 accidents (of which 672 were survivable) that occurred between 1968 and 2007 involving large transport category turbojet and turboprop western-built aircraft operating in a passenger or passenger/cargo role.

Over the study period, there was a marked reduction in the total accident rate both for the world fleet and the combined U.S. and Canadian fleets. This reduction is apparent when the accident rate is measured on a per flight, per passenger, or per revenue passenger mile basis.

The survivability of accidents has also shown a marked improvement over the study period with a greater proportion of accidents being survivable and a marked increase in the proportion of occupants surviving an accident. These improvements are apparent in both the world fleet and the combined U.S. and Canadian fleets.

It would seem that fatalities attributable to impact represent a larger proportion of the total number of fatalities in survivable accidents than those that are caused by fire.

Micro fuel cells are an alternative to batteries as a portable source of electricity. Unlike a battery, which stores electricity, a fuel cell chemically reacts a base fuel with oxygen from the air to generate electricity. A fuel cell is recharged by simply replacing the fuel. The potential flammability of the base fuels is a concern when carried onboard an aircraft.

A series of tests were performed to evaluate the flammability hazard associated with fuel cell fuel cartridges. Tests were conducted with various fuel chemistries including methanol, formic acid, butane, hydrogen gas, and borohydrides. The response of each fuel cartridge to an external alcohol fire was evaluated.

Most of the fuels tested were flammable. The cartridge containing formic acid did not ignite under the test conditions. Butane produced the most vigorous fire. Heating hydrogen gas stored in a metal matrix caused breaching of the enclosure allowing the gas to escape and ignite. Borohydrides were difficult to ignite but gave off a flammable fume when heated and were capable of deep-seated exothermic reaction. It was found that the cartridge material can have a significant effect on flammability. Metal cartridges protected the fuel from an external fire better than plastic cartridges. Halon 1211 was effective against all but the deep-seated borohydride exothermic reaction.

The Federal Aviation Administration (FAA), as part of its hidden in-flight fire mitigation program, developed an improved flammability test method for aircraft electrical wiring insulation materials (including jackets and other wire protective materials). A comprehensive fire test research and development (R&D) project was conducted on aircraft electrical wiring insulation materials in an effort to continue mitigating the threat of in-flight fires. Previous work at the FAA and the National Fire Protection Association have indicated that the current FAA-required 60-degree Bunsen burner test for electric wire was inadequate to qualify wire when bundled and subjected to a severe ignition source. A literature search and in-house fire tests were conducted during this effort. The results of the literature search indicated that there was no small-scale flammability test standard available that considered radiant heat and wire bundling in its specifications or acceptance criteria that included burn length and after-flame extinguishing time; therefore, an improved flammability test standard for aircraft wiring was required. In-house fire tests were conducted to develop an improved flammability test and provide support data; tests included the current FAA-required 60-degree Bunsen burner test, the microscale combustion calorimetry test (ASTM D 7309-07), the thermogravimetric analysis (ASTM E 2550-07), the intermediate-scale fire test, and the radiant heat panel test. From this R&D effort, an alternative radiant heat panel test method was developed. This method was effective in evaluating the in-flight fire resistance qualities of aircraft electrical wiring insulation.

Thermoplastics and composites made from hydrocarbon polymers can improve the affordability, strength-to-weight ratio, and durability of manufactured products. Unfortunately, the use of these materials in aircraft and other vehicles is limited because of their inherent flammability. An alternative, lower-cost strategy is to develop environmentally benign additives that significantly reduce the flammability of commodity polymers. In this study, polymers blended with graphite oxide (GO) and its functionalized analogs were evaluated as cost-effective, fire-resistant materials for aircraft and other forms of mass transportation. GO polymer nanocomposites were prepared by dispersing 1, 2.5, 5, and 10 weight % GO in polycarbonate (PC), acrylonitrile butadiene styrene (ABS), and high-impact polystyrene (HIPS) for the purpose of evaluating the flammability and materials properties of the resulting systems. The overall morphology and dispersion of the GO within the polymer nanocomposites were studied by scanning electron microscopy and optical microscopy; the GO was found to be well-dispersed throughout the matrix without formation of large aggregates. Mechanical tests were performed using dynamic mechanical analysis to measure the storage modulus, which increased with GO loading for all polymer systems. Microscale oxygen consumption calorimetry revealed that GO could reduce the total heat release and heat release capacity of HIPS and ABS. Nanocomposites of GO with PC demonstrated very fast self-extinguishing times in vertical open flame tests. Heat release rate of the 2.5 weight percent GO nanocomposites measured in a cone calorimeter in flaming combustion was reduced 25% and a surface energy balance was used to explain the results in terms of enhanced radiant energy losses by the GO.

The processes that take place in the condensed phase of a burning polymer play an important role in the overall combustion. Quantitative understanding of these processes is critical for prediction of ignition and growth of fires. During the past decade, a significant effort has been made to develop mathematical models of polymer pyrolysis. In the current study, a model of burning of two widely used charring polymers, bisphenol A polycarbonate and poly(vinyl chloride), was developed and validated. The modeling was performed using a flexible computational framework called ThermaKin, which was developed in the Federal Aviation Administration laboratory. ThermaKin solves time-resolved energy and mass conservation equations describing a one-dimensional material object subjected to external heat. Most of the model parameters were obtained from the results of direct property measurements, which is a key distinguishing aspect of this work. The model was employed to simulate cone calorimetry experiments performed under a broad range of conditions. Possible sources of error in the model parameterization were analyzed. The results of this study demonstrate that a one-dimensional numerical pyrolysis model can be used to predict the outcome of cone calorimetry experiments performed on a charring and intumescing polymer. A simple submodel based on the properties of graphite and a single adjustable heat transfer parameter provides a reasonable approximation to the carbonaceous char description.