Julius J. Gassmann

The degree to which fire in large cargo compartments may be suppressed by shutoff of ventilation was investigated. Results of the tests indicated that this action alone would not protect the fuselage of large cargo aircraft from severe fie damage.

Peak air temperature occurring during fire increased significantly with compartment size from 1,000 to 2,000 cubic feet and were similar with further increase in size from 5,000 cubic feet. Temperatures in the order of 1,800°F were reached in these larger compartments.

An increase in percent loading resulted in a more severe fire condition for compartment volumes of all the sizes used in this program.

A single cargo fire test indicated the use of bromotrifluoromethane at the time of detection and ventilation shutoff may be an effective means of greatly reducing peak temperatures and pressures and providing a longer control time.

Martin A. Uman

Laboratory sparks a few meters in length can be used to simulate lightning current rates-of-rise and peak values and to simulate some of the temporal characteristics of the lightning channel temperature. Long spark generators are inadequate for producing a simulation of the continuing current phase of lightning. Long sparks cannot be used to produce a simulation of the shock wave 'due to lightning except. in that the spark data can be scaled by theory to predict the characteristics of the ligbtning shock wave. A short discussion is given of the several types of lightning which might be encountered by an aircraft. The validity of long-spark testing in determining the likely points of strike of a lightning discharge to an aircraft or other structure is. briefly considered.

Merritt M. Yancey, Richard T. Headrick

Subject: Use of available rubber, plastic and other materials to reduce probability of fire in fuel tanks during and after survivable crashes.

Techniques investigated apply to integral tanks and bladder cells as well. General contributions include prevention of original penetration, containment of penetration, maintenance of fuel integrity even with failure of above systems, change in characteristics of fuel expulsion from major wound to non-vapor, low flow liquid leak; flame and explosion suppression and surge attenuation. Proper selection of “building blocks” to optimize desired performance characteristics indicates a major contribution is available with slight, almost unmeasureable displacement of usable fuel and addition of weight. Structures so protected my be inspected.

H.D. Whallon, A.T. Peacock, L.D. Christensen

A previous study described in FAA Final Report No. DS-70-l examined the technical aspects of using gelled or emulidifed fuel in a DC-8-62 commercial jet transport and identified associated problems. This study examined the economics of jet fleet conversion to the use of 2 percent gelled fuel. Based on the technical findings, a DC-8-62 modification program was outline, costed, and analyzed. Based on the DC-8-62 analysis, it was estimated that conversion and operation for the ten years 1972-81 of all U.S. air carrier jet passenger airplanes would add about four billion dollars to their operating costs for the decade. This is approximately a 4.5 percent increase in total operating costs.

The following changes to Federal Test Method Std. No 191 dated December 31, 1968 have been approved by the Commissioner, Federal Supply Service, General Services Administration for the use of all Federal agencies.