National Transportation safety Board

This publication presents the record of aviation accidents involving revenue operations of U.S. Air Carriers including Commuter Air Carriers and on Demand Air Taxis fro calendar year 1990.

The report is divided into three major sections according to the federal regulations under which the flight was conducted - 14 CFR 121, 125, 127 scheduled 14 CFR 135, or Nonscheduled 14 CFR 135. In each section of the report tables are presented to describe the losses and characteristics of 1990 accidents to enable comparison with prior years.

Patricia Cahill

Full-Scale fire testing was conducted in a furnished aircraft cabin to compare a currently used thermoplastic material with low heat and smoke release characteristics used in forming seat components. This testing was conducted due to questions concerning the exemption of seat components from the heat release and smoke requirements mandated for certain large surface area components in the aircraft fuselage. Results of the full-scale testing showed no significant difference in temperature, smoke levels, or oxygen depletion between the two materials. While carbon monoxide and carbon dioxide emissions were slightly higher with the currently used material, it cannot be concluded that this material was the cause. Based on the overall data, it appears that the small amount of seat component material is not significantly contributing to increased fire hazards.

Bishan Azad, Paul Poston

'This report presents a data base and a methodology for analyzing the feasibility of using antimisting fuel in the commercial aviation fleet and ,includes: a classification scheme developed to analyze major portions of the aircraft fleet; review of the available information on antimisting fuel; analysis of data collected on aircraft operations; and use of' life-cycle costing techniques to analyze the potential impacts of introducing antimisting fuel on a fleet-wide basis and segmentally. Aircraft were classified by number of engines and type of service. For each aircraft group, data were collected on the physical, operational, and economic factors that could facilitate or impede the introduction of antimisting fuel into specific portions of the fleet. These data were analyzed to determine if there are significant advantages to segmental introduction of antimisting fuel and, if so, which portions of the fleet are the most likely candidates for early introduction of antimisting fuel.

Analytical findings indicate that fleetwide introduction of antimisting fuel would maximize the benefit in terms of increased safety. However, segmental introduction may be preferable in terms of lower costs tand potential capacity constraints. Furthermore, the importance of two-engined, regular-bodied turbofan aircraft in the, feet, combined with the relatively low anticipated cost impacts in this segment, suggest that these aircraft may be the best candidates for early introduction of antimisting fuel.

Louise Speitel

A method of collection and analysis was developed to determine the concentration of water vapor in full-scale aircraft cabin fire tests as a function of time. Specialized collection tubes were developed which selectively trap water vapor. Particulates are filtered out of the sample stream and light fixed gases such as CO, CO2, O2, methane, propane and butane pass through the tube. The gas collection sections of the tubes are surrounded by ice-water to maximize collection efficiency of the desiccant packing material. The percentage of water in the test atmosphere is calculated based on the weight gain of the tube and the volume of sample drawn. The flow is controlled by a calibrated needle valve, downstream of the sampling assembly, held at a constant temperature. The method was validated by analyzing selected components of a sample tube from a full-scale fire test by Thermo gravimetric Analysis.

Margaret Harkleroad, James Quintiere, William Walton

The purpose of this study is to develop a fire-testing method that relates material ignitability and flame spread in the creeping mode. The analytical,approach involves parameters and solutions arising from transient heat condition to a semi-infinite solid. Experimental data are generated on an apparatus employing a radiant panel to provide a varying heat flux to test specimens. Flame spread rates and ignitioft events are measured against incident radiation and exposure time. The flame-spread data for given materials are correlated for varying exposure conditions by plotting the inverse square root of the flame-spread velocity against a product of the heat flux and a time function. The test and analysis results are shown for six diverse materials representative of aircraft (interior panels, carpeting, arid seat cushions) and buildings (plywood, polymethyl methacrylate, and rigid 1oam).