Richard Hill

Full-scale tests simulating engine combustion section thermal failures (burn-through) were conducted using a J57 engine (cowled and uncowled) to determine the feasibility of detecting a burn-through prior to its occurrence by monitoring engine skin temperature. Results of the yesys indicated that as few as four thermocouples, located 90 degrees apart around the diffuseer case and/or burner can case, could detect a burn-through prior to engine case rupture.

Ralph J. Cato, George H. Martindill, Joseph M. Kuchta

The effectiveness of Halons 1301 (CF3Br), 1202 (CF2Br2), and 1211 (CF2C1Br) as possible explosion suppressants for aircraft fuel tanks was investigated in ignitions with small charges of an IM-11 incendiary powder (Ba(NO3)2Mg-A1) and 30-caliber incendiary ammunition. Ignitions with the incendiary powder in a 74-gallon fuel tank indicated that over 8 volume percent Halon 1301 is required to completely quench flame propagations of near-stoichimetric n-pentane mixtures and limit the pressure rises to less than 5 psi; these high Halon concentrations were also required under gun firing conditions using the 30-caliber ammunition. The critical Halon requirements for quenching the incendiary ignitions of n-pentane-air mixtures did not differ greatly for the three Halons investigated in this work.

Other experiments were conducted in a 216 ft chamber to evaluate the effectiveness and toxicity hazard of Halon 3800 (C3F8) in extinguishing Class A fires by the total flooding mode. This agent was less effective and produced a greater toxicity hazard than Halon 1301 (CF3Br) in extinguishing cotton sheeting or paper sheeting fires. Approximately 10 to 12 volume percent Halon 3800 was required for extinguishing cotton sheeting fires, although incandescent burning was possible after extinguishment in some cases. Product HF concentrations were as high as 2500 ppm, depending upon the extinguishing conditions. Some comparison data are also given from total flooding experiments with liquid nitrogen, which was much less effective than Halon 3800 in extinguishing cotton sheeting fires.

S.L. Imbrogno

Small-scale fire tests were conducted on sections of an aircraft loading walkway to determine its ability to provide protection to deplaning passengers in the event of a fuel-spill type fire adjacent to the walkway.

John F. Marcy

The intention of this effort was to (1) study the smoke emission characteristics of a selected number of aircraft electrical wiring with different types of plastic insulation coverings and (2) develop minimum performance standards from an analysis of the test results and other technical data that may be useful to Flight Standards Service in preparing a Notice for Proposed Rule Making (NPRM) limiting the maximum allowable smoke emission from interior materials within safe and/or reasonable levels.

Stephen L. Kaplan

Smoke and toxic gas generated match direct fire damage as hazards when plastics burn. Attempts to hinder burning by incorporating flame-retardant additives usually cause increased smoke and gas evolution from flammable synthetic materials. This is where the thermostable polymers can help.