Page:CAB Aircraft Accident Report, United Airlines Flight 227.pdf/21



Mr. George S. Moore

Director

Flight Standards Service

Federal Aviation Agency

Washington, D. C. 20553

Dear Mr. Moore:

This is a further recommendation based on our investigation of the United Air Lines Boeing 727, N7030U accident at Salt Lake City, Utah, on November 11, 1965. As you know, 43 of the 91 occupants died as a result of this accident. Our preliminary findings indicate that none of these fatalities were due to traumatic injuries but all died from suffocation during the resultant fire. This is evidenced by the elevated carboxyhemoglobin concentrations in the victims and lack of trauma.

We are conducting an extensive study in the human factors area to determine how the survivors evacuated the airplane, the difficulties they experienced and the time it took them to evacuate. It is hoped that we will be able to determine the fire progression in the occupiable area of the cabin. Preliminary information indicates that the interior furnishings contributed greatly to the spread of fire and the emission of heavy black smoke, both of which contributed to the fatalities.

We understand that the Aircraft Development Service of FAA has just completed a study of air transport passenger cabin fires and materials and that their report will be published shortly after the first of the year. We have been advised that the aforementioned fire tests have disclosed a number of deficiencies in the materials presently being installed in aircraft interiors and that materials are available which would be far superior to those being used today.

We do not have complete information regarding the testing methods used during the aforementioned study by the Aircraft Development Service. We believe that the toxicity of the resultant gases produced by the combustion of various combinations of materials used in aircraft interiors might be worse than those produced by the materials individually. If the tests did not include such determinations it is recommended that they be expanded to test various combinations. Additionally these combinations should be tested with fuels carried in aircraft.