Volume 42, Issue 3 (May 1997)
Soil Science Contribution to an Airplane Crash Investigation, Ruidoso, New Mexico
Investigation of a plane crash near Ruidoso, New Mexico revealed foreign biological material and soil in the fuel system of the engine. In-flight accumulation of the soil was claimed by the plaintiffs as one cause for the crash. EDX X-ray maps and spectra were taken by the plaintiff's experts and showed patterns consistent with silicates. The defense hypothesis was that the soil accumulated after the crash while the debris was in a storage yard and exposed to the elements for several months. Many of the parts were covered in muddy water (mud puddles) before the plaintiffs investigated the parts for soil accumulation. The soil composition on the parts was found to be similar to that in the storage yard. Further, the plane was exposed to an intense fire after the crash, and if the soil had been subjected to such temperatures it would have oxidized to a red color. Soil from the storage yard, the crash site, and from an area in Montana where the plane landed on an unpaved runway was exposed to heat up to 1,000°C in the laboratory and the soil turned red. Soil from the fuel component was not red, although a small piece adhering to the outside of the wreckage was red suggesting exposure to the post-crash fire. It was concluded that the engine parts were contaminated with soil after the crash, and that pre-crash accumulation of soil, as a supplement or alternative to biological contamination, was not a viable explanation.