colors and are embossed in a wide selection of textures and gloss levels. These films are designed to meet rigid airline and manufacturing demands involving color, gloss, and texture. Although these characteristics are largely subjective and therefore difficult to specify and measure, they must nonetheless be consistently matched. Typical panel constructions are shown schematically in Figure 2-3.
Fire-resistant textiles have presented some especially difficult problems. Aesthetics demand that upholsteries, draperies, carpets, and tapestries be available in a wide variety of colors and have tight tolerances for look, feel, and durability. New-generation synthetic fibers with improved fire resistance have had a natural dark color that has essentially precluded their being pigmented in light colors, so the lack of availability of a wide variety of colors has greatly limited their acceptance for aircraft application (Hasselbrack, 1995).
The major material that is used for upholstery and drapery has been fire-retarded wool, with some use also made of a fire-retarded polyester, both of which meet the fire-resistance requirements and can also be dyed in an unlimited range of colors. Tapestries are held to more stringent flammability requirements than upholstery and drapery. It has been difficult to formulate a fire-retardant scheme for wool that allows it to meet the more-stringent requirements. Therefore, tapestries currently have to be fabricated of the new synthetic materials, with a fairly limited color palette or of wool/synthetic hybrid fabrics. This restriction has, to some extent, discouraged the use of tapestries. Other decorative schemes of less aesthetic appeal are being used in place of tapestries.
There are numerous other material types used in various applications. Examples are summarized in Table 2-1.
The air transport industry and its regulators have achieved an outstanding safety record (as described in Appendix B) by placing an intense, vigorous, and unrelenting priority on the safety of the air transportation system. To maintain and even improve this excellent aviation safety record, the people responsible for the operation and maintenance of aircraft—flight crews, airplane mechanics, and air traffic controllers—are selected and trained according to rigorous safety criteria.
Aircraft are designed to operate routinely under extreme conditions, that is, both at altitudes where human life cannot be sustained outside the aircraft and on the ground while taking off and landing at high speeds. The amount of fuel necessary to move such large and highly engineered machines over several thousand miles while at an altitude of seven or eight miles is tremendous. For example, the heat energy contained in the fuel carried by a 747 (more than 50,000 gallons of jet fuel) is more than 20 times as much as would be needed to heat up and melt the entire airframe.
Minimum safety standards for aircraft design, manufacture, and operation are established by FAA regulations. In addition to the regulatory mandates, aircraft manufacturers use supplemental design criteria that go beyond the regulatory requirements (for example, see Boeing Commercial Airplane Group, 1977; Airbus Industries, 1979).
The criteria for interior safety requirements were developed for normal operation (which includes all non-crash-related incidents) and for several survivable crash-related scenarios (crashworthiness). Although there are many types of criteria, the major ones are:
structural strength and stiffness,
fire resistance (includes control of smoke generation),
interior configuration and emergency evacuation, and
emergency oxygen systems.
of these, fire resistance structural strength and stiffness have the most impact on research for improved fire- and smoke-resistant materials.
Although there are regulations concerning physical and mechanical properties as well as configuration and layout requirements, the FAA regulatory requirements for interior furnishings are based, in large part, on flammability. The flammability mandates for transport aircraft are listed in FAR 25.853, FAR 25.855, and FAR 25.869. For most furnishings (except cabin liners, seats, and cargo liners) these comprise Bunsen burner tests to characterize resistance to ignition and ability to sustain a flame. In addition to ignitability requirements, cabin liners are subject to additional requirements that