Don W. Conley

Information was obtained on the effectiveness of helicopter downwash and ground foam equipment in extending the escape time for aircraft occupants in a post-crash fire environment by burning five C-97 aircraft under similar conditions. Additional tests, not involving C-97 aircraft, were conducted relative to rescue path studies.

Test data indicated that helicopter downwash extended the escape time when fire existed solely on the upwind side of a C-97 fuselage, but the escape time when fire was on both sides or solely on the downwind side of the fuselage. It was also found that helicopter downwash provided a considerable reduction in the radiant heat and air temperature in a simulated rescue path.

For the standard fire condition used and the equipment employed, the ability of ground crews to extend the escape time was found to be dependent upon the preburn time and the fuselage integrity with respect to emergency doors open or closed. An escape time of 50 seconds was computed for C-97 with emergency doors open as compared to 138 seconds or a C-97 with emergency doors closed. Test results amplify the need for a quick arrival of extinguishing equipment and a capability for a quick “knockdown” and control of the fire.

E.K. Litchfield

Severe explosion hazards could result from a massive spill of non-hypergolic fuel and oxidizer of a missile propulsion system; this problem would be especially severe with the high-energy systems where one or both of the propellant components are cryogens. The sensitivity of two such systems, liquid hydrogen + solid oxygen + diluents and liquid oxygen + solid \hydrocarbon + diluents, has been investigated employing a projectile impact \to determine the shock required to detonate these mixtures. With no diluents, each explosive system is initiated by a shock stimulus of 1.0 to 2.5 kbar. The explosive yields are such that 1-lb cryogenic mixture is equivalent to 0.6 to 2.0 lb TNT. Sodium chloride, nitrogen, and methyl chloride had inert desensitizing effects upon the liquid hydrogen mixtures but did not reduce the explosive yield. Sodium chloride and nitrogen desensitized the liquid oxygen system; sodium chloride or water ,reduced the explosive yield. of this system.

"Large volumes of detonable, gaseous hydrogen-oxygen mixtures would result from a massive spill of liquid hydrogen-liquid oxygen. Inhibition of detonation initiation by dry powder particle additives was investigated. The powder additives produced insignificant inhibition in comparison to that produced by gaseous diluents.

Flammability limit determinations of four additional halogenated hydrocarbons are included in a discussion of the characteristics of 10 such compounds. Most of the compounds were flammable in oxygen atmospheres at temperatures below 2000 F; their combustion products included toxic halogens or halogen halides.

John Marcy, E. Nichols, J. DeMaree

A study of the combustion characteristics of interior cabin materials was made to establish the relative fire hazards inherent in the use of such materials in passenger air transport.

Stanley Mohler

More than one hundred years ago Lord Tennyson prophesied “Saw the heavens filled with commerce, argosies of magic sails, pilots in the purple twilight dropping with costly Bales. He possibly did not foresee certain complications associated with such aerial commerce, particularly the “dropping down” with more than the usual drop force.

The “costly bales” which comprise the topic of this paper, are the soft protoplasmic masses encased within aircraft. The aim of emergency evacuation is to get these soft protoplasmic masses from the interior of a distressed aircraft to the exterior, without irreversible damage.

This paper will focus on what we term the human factor in emergency evacuation. Anything, which unduly impedes the processes of emergency evacuation, is deleterious and must be avoided. The word unduly is used because certain impediments, or “constraints”, are essential to an orderly evacuation. In the absence of constraints, utter chaos is generated, and, as was indicated in a recent survivable crash landing of a transport-type aircraft, tragedy may result. The evidence indicates that the loss of 77 lives in the conflagration which followed the survivable crash landing, resulted from the inability of the occupants to open the main door, possibly greatly aggravated by the pell-mell collection of the occupants against the door.

T.G. Lee

A method is described for the rapid in situ determination of the “thermal inertia for surface heating” (kpc product) of materials using a sensitive infrared detector. Experimental measurements are given of the effect of moisture content on the thermal inertia and on the surface flammability of selected cellulose materials conditioned to equilibrium at relative humidity's ranging from 0 – 99 percent. It is shown that (1) the thermal inertia of uncoated hardboard and fiberboard material can be represented s a linear function of its moisture content, (2) that if the appropriate thermal properties are used, the flame-spread factor is inversely proportional to thermal inertia, and (3) the unbroken surface film of coated materials results in a lower ignition sensitivity than that predicted on the basis of thermal inertia.