Louise C. Speitel

The development of a survival model for post-crash aircraft cabin fire is described in this paper. Its development is based on an extensive review of the literature on the toxicity of combustion gases and on thermal hazards. This model is to be used as a predictive tool to gauge human survivability in full scale aircraft cabin fire tests. The extensive literature search was conducted for carbon monoxide (CO), carbon dioxide (CO2), hydrogen cyanide (HCN), low oxygen, hydrogen fluoride (HF), hydrogen chloride (HCI), hydrogen bromide (HBr), nitrogen dioxide (NO2), sulfur dioxide (SO2), acrolein (CH2-CHCHO), and heat exposures. Those studies by various investigators of exposures to single and mixed gases on humans, primates rats and mice at different physical activity levels were compared. Regression equations were derived from those studies to give the best fit to gas exposure concentration and duration data. The equation judges to best model the human escaping from an aircraft cabin was selected for each gas. The survival model uses incapacitation data to obtain a fractional effective dose (FED) for incapacitation (FED1) and lethality data, inclusive of post exposure deaths, to obtain a FED for lethality (FED1). The exposure time required for either FED1 or FEDL to reach unity, using a projected set of gas concentrations, represent the exposure time available to escape from the specified fire environment or to survive post exposure, respectively. The effect of CO2 in increasing the uptake of other gases was factored into the concentration term in the FED equation for all gases with the exception of CO2 and oxygen. Higher respiratory minute volumes due to CO2 exposure were found to be important factor in predicting the time available to escape. This FED-based model can be applied to the evaluation of the toxicity of smoke in computer modeling of aircraft fire situations.

R. Tapscott, J.A. Brown, L.E. Dvorak, A. Gupta, J.W. Mossel, E. Jacobson, J. Gibson, K. Metchis, T. Simpson, L. Speitel, R.A. Tetla

This report contains summary of available fire suppression agents, their properties and applicability in the various aircraft applications. Classes of agents, with presently available agents listed, are recommended for use in the development of test protocols. The test protocol developed for a class of agents can be used, with minor modifications, to test all agents belonging to that class.

Vanessa J. Breechling, Floyd Spencer

This report details the validation analysis of PRI's Magneto-Optic/Eddy-Current Imager (MOl). The analysis includes both a reliability analysis of the system and an economic analysis of the potential benefits and costs related to its use.

The reliability analysis consisted of blind inspections of well characterized panels simulating a fuselage lap splice. The panels contained cracks of known sizes emanating from under rivet heads on the upper row of rivets. The MOl inspection times were less, on average, than were inspection times using a sliding probe. Twenty percent reduction in inspection times is consistent with the data obtained and is used as a baseline for the economic analysis.

The economic analysis considers the effects of individual factors that contribute to the cost effectiveness of the MOL The possible returns on the investment for a representative maintenance facility lare calculated using the net present value methodology. Specific characteristics are defined for the representative facility; and then they are varied to account for the differences in the. maintenance community.

For a facility which can take full advantage of the potential time and labor savings associated with implementation of the MOl, the investment in MOl would generate a positive return in less than one year. In this fully competitive scenario the cumulative net present value at the end of the tenth year would be over $160,000. Under a semi-competitive scenario, the not present value is negative throughout the life cycle of the investment.

F.A.A. Technical Center, Transport Canada Aviation and Joint Aviation Authorities

Cabin safety presents challenges common to all aviation authorities. Related issues and needed research must be accomplished through a totally integrated program.

To enhance their respective research capabilities, the U.S. Federal Aviation Administration (FAA) and the Transport Canada Aviation (TCA), the aviation authorities of North America, and the Joint Aviation Authorities (JAA), the aviation authority of Europe, have been doing in rulemaking, agreed to cooperate in research the transport category airplane cabin safety. The FAA/JAA/TCA Cabin Safety Research Program is the formalization of this agreement.

Specically, the goal of the Cabin Research Program is to provide a mechanism for the coordination of pertinent activities and, as appropriate, the conduct of cooperative joint, and complementry programs to the benefit of the three authorities.

For the purpose of this program, cabin safety is intended to address acute eventss/condition which can be dealt with by changes within (or closely associated with) the cabin. Although in-flight issues form an integral part of cabin safety, the primary focus is postcrash survivability the principal elements of which are structural crashworthiness, fire safety, evacuation and overwater survival.

The foremost decision-making tool to identify and access the potential of needed research (and of past improvements) are a probailistic risk analysis model and a cabin safety accident/incident information data bank/base.

William T. Westfield

A review of regulatory actions taken by the Federal Aviation Administration (FAA) over approximately the past thirty years was made to identify which of these actions were preceded by, or triggered by research and development (R&D) programs. The focus of this analysis was limited to those actions and R&D that pertained to aircraft safety. Research was frequently requested to be performed by the industry elements themselves, namely the engine and aircraft manufacturers, independent research organizations, or by academia. As the FAA experience with the operational fleets grew, some research was accomplished by the internal FAA and governmental organizations, such as the Civil Aeromedical Institute or the Technical Center, and the National Aeronautics and Space Administration.

The review revealed that the rulemaking actions were supported quite frequently by research. While it is true that major accidents brought the attention to technology unknowns, and the subsequent rulemaking to prevent the problem appeared to be moving too slowly to provide solutions to the need, the review showed many risks have been reduced, (cabin fires, inadvertent collision with terrain, faster evacuation, to name a few) through the performance of research.