NASA White Sands Test Facility and The Department of Mechanical Engineering at The University of Queensland have begun a collaborative research program investigating the effects of gravity on the burning characteristics of metallic materials. This work builds upon the earlier short-duration ground-based testing where it was indicated that certain metallic materials that would not sustain combustion at high-oxygen pressure in normal gravity, appeared to support combustion at a relatively lower oxygen pressure in microgravity. These earlier tests, of 2.2 s duration, did not allow slow burning materials, or materials that were difficult to ignite, adequate time to propagate. A specific objective of this research program, therefore, was to perform microgravity tests of substantially longer duration thus allowing these materials, if flammable, adequate time to propagate along the test specimen. The NASA Johnson Space Center's KC-135 Reduced Gravity Test Aircraft, providing a microgravity duration of 24 – 26 seconds per experiment, was selected for these tests. This paper provides a description of the test system designed and fabricated to conduct these tests, the procedure used to conduct flight based tests aboard NASA Johnson Space Center's KC-135, and an overview of the actual flights and the experimental results. System modifications made in preparation for the second series of flight tests, as a result of experiences during the first series of tests, are also described. Nine metallic materials were tested in this program including iron, nickel, copper, cobalt, aluminum, aluminum/10% silicon-carbide, titanium, Monel K-500, and 316 stainless steel. The results of these microgravity tests, consistent with the results from the earlier short-duration tests, are described and comparisons made for these materials with results obtained in similar normal gravity tests.