Advanced Concept in Aircraft Crash Firefighting Using Carbon Tetrafluoride

The objective of this effort was to establish the feasibility of replacing a potentially lethal aircraft cabin environment with a cool habitable atmosphere which is non-supportive of combustion during passenger evacuation in fire emergencies.

Four large-scale experiments were performed in the completely instrumented cabin of a DC7 aircraft employing both Class A and B combustible materials. Three experiments were performed using the habitable inert atmosphere (27-volume percent CF4) discharging at the rate of 3,300 cubic feet per minute into the aircraft cabin through, a window exit. For comparative purposes, the fourth experiment was performed using neat CF4 discharged from two simulated points of fuselage penetration bya ballistically-powered aircraft skin penetrator nozzle. Both of these prototype fire extinguishing systems were designed to be employed by airport crash-fire-rescue services to extinguish aircraft cabin and compartment fires.

The CF4-air atmosphere was capable of extinguishing nonsurvivab1e Class A and B cabin fires within 125 seconds or less during which time the cabin temperature was rapidly reduced and visual acuity slowly improved by smoke dilution during the
Class A fire tests. Fire extinguishment by means of neat CF4 at the same discharge rate required approximately twice as long, and visibility within the cabin did not improve during the duration of the experiment