APPRAISAL OF THE HAZARDS OF FRICTION-SPARK IGNITION OF AIRCRAFT CRASH FIRES

摘要

A study was made to determine if common aircraft metals produce friction sparks capable of igniting combustibles that might be spilled in an airplane crash. Samples of aluminum, titanium, magnesium, chrome-molybdenum steel, and stainless steel were dragged over both concrete and asphalt runways while a combustible mixture of gasoline, JP-4 fuel, kero?sene, or preheated oil was sprayed around the sample.nNo ignitions occurred from sliding aluminum at bearing pressures up to 1455 pounds per square inch and slide speeds up to 40 miles per hour. From a study of these results and of related literature, it is believed that aluminum would not be an ignition source even at higher bearing pressures and slide speeds. Titanium, magnesium, chrome-molybdenum steel, and stainless steel produced friction sparks that ignited the com?bustibles at sliding speeds and bearing pressures well below those that could be expected in a crash.