Louise C. Speitel

This document describes the methodology for identifying unknown pump motor housing materials suspected of being involved in the propagation of a ramp fire aboard a DC-9 aircraft. The DC-9 was gutted from a fire believed to have originated in the vicinity of this lavatory pump motor. The ramp fire started after power up in Barranquilla, Columbia. The National Transportation Safety Board requested the FAA to identify the pump motor housing components to assist the investigation of the incident.

The flammability of the identified pump motor housing components was reviewed. The acetal copolymer, the principal component, is known to sustain continued combustion in the presence of a small ignition source and may have contributed to the spread of the fire. Acetal polymers may not be an appropriate fire-safe material for this application.

Ken Posey, Jr., Dr. Richard Schleicher

Several additives for gelling turbine fuel were studied and tested to predict (1) their ability to reduce or prevent fuel fire in aircraft crashes and (2) their ability to maintain the turbine engine quality of the fuel. An additive known as N-coco- Y -hydroxybutyramide (CHBA) was found to give a strong, solid gel when mixed in the ratio of 1.5 percent to the weight of the fuel. Laboratory scale impact tests in the presence of an open flame were made of several types of gels. The CHBA gave the best results and reduced the amount of flame generated by 85.2 percent as compared to ungelled fuel. Flame propagation rate on the surface of the gel was less by 96.7 percent. This gel is easily liquefied by heating it to 130° F.

Chemical and physie-al tests of the CHBA liquefied gel indicate that it meets turbine engine fuel requirements in all respects except freezing point, which is necessarily high because of the solid nature of the gel. Five gallons of liquefield CHBA gel were burned in a 0.75 gallon per hour standard commercial oil burner having a nozzle with a 60 degree cone orifice. Ignition was instantane QUS and the material was visually observed to burn with a smooth, steady flame without leaving deposits or causing corrosion. In a separate test, the solid gel itself was pumped to the nozzle with a gear pump. It burned in the same manner as the liquefied gel.

Timothy Marker

This report summarizes the findings of Subgroup 4 of the International Materials Fire Test Working Group, which deals with issues involving fire test approval following renovation and repair to interior material systems. The main problem associated with material system renovation is the difficulty in conducting certification tests due to lack of the appropriate base substrate. The subgroup investigated this problem and made suggestions of alternate testing methods which ranged from the use of a singular common substrate to the use of multiple substrates, or surrogates, to run the ce:rtification tests on. The use of surrogate materials, although complex, was the only testing method discussed which could insure that a renovated system would remain in compliance without actually testing the final, in-service material system.

Fire test approval following repair of interior systems was another problem area. Most repairs involve the use of plastic-based fillers which are used to fix cracks and dents in panels and also to smooth surfaces prior to finishing with paints or laminates. Currently, there is no test method for certifying the use of fillers, which have the potential to increase the heat release rate and smoke production of interior panels.' The subgroup participants discussed possible testing methods for certifying fillers including the system format and the spatula filler only format, but remained divided. on the issue. In order to establish the pass/fail criteria for the filler-only method, several different types of spatula fillers were tested, and the results indicate that a majority of the fillers could only pass the 100/100 criteria in the OSU apparatus. Fire test approval following repair of cargo compartment liners was another issue investigated by the subgroup. In contrast to interior panel repair, there is currently a test procedure for certifying repairs made on cargo liners, which generally consist of adhesive patches placed over damaged areas. The current certification procedure encompasses two tests: one for patch material burnthrough resistance, the second for patch adhesion. In addition to this procedure, the subgroup made several recommendations to insure that repairs which meet the certification test will not catastrophiGally fail during actual fire conditions.

Richard E. Lyon

The goal of the Federal Aviation Administration's Fire Research Program is to eliminate fire as a cause of death in aircraft accidents. The Fire Research Program is a long-range research effort which includes advanced materials in a systems approach to improved aircraft cabin fire safety along with fire prevention, detection, and control. The objective of the Advanced Fire-Safe Materials portion of the program is to discover the fundamental relationships between the composition and structure of materials and their behavior in fires to enable the design of a totally fire-resistant cabin for future commercial aircraft. Research will be basic in nature and will focus on synthesis, characterization, modeling, and processing of new materials and materials combinations to improve the fire performance, increase the functionality, and reduce the cost of next-generation cabin materials.

Richard Lyon

The fire response of a potassium aluminosilicate matrix (geopolymer) carbon fiber composite was measured and the results compared to organic matrix composites being used for infrastructure and transportation applications. At irradiance levels of 50 kW/m2, typical of the heat flux in a well developed fire, glass- or carbon-reinforced polyester, vinylester, epoxy, bismaleimde, cyanate ester, polyimide, phenolic, and engineering thermoplastic laminates ignited readily and released appreciable heat and smoke, while carbon-fiber reinforced geopolymer composites did not ignite, burn, or release any smoke even after extended heat flux exposure. The geopolymer matrix carbon fiber composite retains sixty-three percent of its original 245 MFa flexural strength after a simulated large fire exposure.