Joseph M. Kuchta

Many fatalities that have occurred in aircraft crashes during take-off or landing have been attributed to the fire and smoke produced following ignition of fue1 dispersed from ruptured fuel tanks. In an effort to reduce the crash fire hazard, the Federal Aviation Agency sponsored a research program in 1964 to determine the feasibility of using thickened fuels in aircraft. Results of this program indicated that the potential fire or flammability hazard is greatly reduced for aircraft fuels containing 1.5 weight percent of CHBA or FAA 1069-1 gelling agent (N-"coco"- hydroxybutyramide) .Although these results were obtained under small-sale simulated crash conditions, similar results were found by the Federal Aviation Agency under full-scale simulated conditions. Other work, particularly that sponsored by the Army, has led to the development of fuel emulsions that also appear promising as "controlled flammability fuels" for aircraft. In the present work the Bureau of Mines was requested by the FAA to develop a method of rating the potential crash fire hazard of gelled and emulsified fuels. The rating system described in this report is applicable primarily to hydrocarbon-type aircraft fuels. Test methods for determining the fuel properties used in the rating system are described in the appendix.

John F. Marcy, Richard Johnson

A study was made of the burning characteristics of some 140 different material for the purpose of obtaining technical data and criteria needed to support current efforts to improve existing Federal Air Regulations governing the use of cabin interior materials in aviation.

Comparative tests were conducted on two groups of materials; one consisting of materials now in use in air transport, and the second materials proposed for future use with superior fire resistance. Measurements were made of ignition time, burn and char lengths, flame-out time, burn rate, heat of combustion, flame-spread index, etc. Two standard laboratory test methods were employed; namely, (1) Federal Standard CCC-T-19Ib, Test Method 5902, Results of the tests were analyzed to indicate major flammability trends for different material classifications. Practical allowable flammability limits based on available materials technology were recommended for increasing the present fire protection requirements of interior materials.

Captain Donald A. Heine

In Phase I of the Cleveland Fire Tests, June 30 and July 1, 1966, a control burn of an aircraft was done to determine the free burn characteristics of an average aircraft cabin interior. Full instrumentation and gas analysis was accomplished to give baseline data for comparison with future tests.

Also, in Phase I, a second aircraft was accomplished to determine whether high expansion foam could be used successfully to extend survival time in an aircraft cabin beyond previously known limits. This test was not successful since it was determined that ingestion of air contaminated with products of combustion/pyrolysis into foam generator prevented formation of the foam. This has been further documented by research done by Williams and reported in Fire Journal (September 1968).

R. Byron Fisher, Paul M. Rich

An acoustic locator beacon was developed and tested in an underwater environment simulating the conditions that might exist when an aircraft crashes into water. The beacons were self-contained, battery-powered, and produced a 10- to 20-millisecond pulse of 35 to 40 kHz at a rate Of I to 4 pulses per second. The locator beacons were designed to be attached to airborne flight data recorders to assist in the recovery of the recorded records for use in aircraft accident investigations following a crash.

The crash environmental tests were conducted using a section of an aircraft fuselage that 8till contained the cabin pressure-bulkhead. The beacons tested were placed in two different representative locations; (1) inside the cabin pressure area, and (2) aft of the pressure bulkhead in the unpressurized area. . The fuselage section was lowered into seawater at depths of 50, 100, and 200 feet off the coast of the Florida Keys. Search run8 were made using a motor powered craft equipped with an acoustic locator receiver. The results indicate that the signals of a fuselage encapsulated locator beacon can be detected at reasonable surface distances (up to 3000 yards) and at depths as low a8 200 feet.

Federal Aviation Administration, Department of Transportation

Advance copy pending issuance of changes to FAR parts 25 and 121