Enhanced Emergency Smoke Venting

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Enhanced Emergency Smoke Venting

E. L. Maylor

This study evaluated two concepts modifying the air conditioning systems of large commercial airplanes to enhance the venting of smoke that may be continuously injected into the passenger cabin during inflight fire emergencies. Data from past fire accidents and airplane tests provided a basis for creating four fire/smoke scenarios and deriving five sets of equations to predict the smoke venting effectiveness of current airplanes and the proposed concepts. Concept A would modify the air conditioning packs by adding high flow modes with dual outflow valves and Concept B would add ram air ventilation with an added dump valve. The estimated costs to incorporate Concept A or B in the U.S. fleet were about 381 or 587 million dollars, respectively. The effectiveness equations predicted that both concepts would provide only slightly significant smoke venting enhancement. Furthermore, the study showed that both concepts would have been negated by reported crew actions and/or fire damage in past fires. It was concluded that current U.S. fleet airplanes will keep a majority of the passenger cabin free of smoke during inflight fires while the air conditioning systems are kept operating.