Application of DNA Profiling in Resolving Aviation Forensic Toxicology Issues

Biological samples from the victims of aviation accidents are submitted to the Civil Aerospace Medical Institute (CAMI) for toxicological evaluation. Body components of aviation accident fatalities are often scattered, disintegrated, commingled, contaminated, and/or putrefied at accident scenes. These situations may impose difficulties in victim identification and tissue matching, thereby in the toxicological analysis of authentic samples and the interpretation of the associated analytical results. The use of DNA typing has been exemplified in the literature to resolve the sample misidentification issue. However, the prevalence of this type of issue in relation to aviation accident forensic toxicology has not been well-established. Therefore, the CAMI toxicology database was searched for the period of 1998−2008 for those accidents/cases wherein DNA profiling was performed. During this period, samples from 3523 accidents were received by CAMI. Of these, there were 3366 aviation accidents wherein at least one fatality had occurred. Biological samples from a total of 3319 pilots were received. Of these, 3275 were fatally injured. The 3319 pilots translated into the equivalent number of aviation accidents. Of the 3319 accidents, there were only 15 (≈ 0.5%) accidents wherein DNA profiling was performed on the biological samples. Six occupants (four fatalities and two injured victims) were involved in one accident and five (two fatalities and three injured victims) in another. Three fatalities occurred in three accidents each, two fatalities in eight accidents each, and one fatality in one accident. In one accident, there were two occupants with non-fatal injuries. DNA profiling was conducted upon the requests of families in two accidents, of accident investigators in three, and of pathologists in four. In six accidents, contradictory toxicological findings—such as selective presence of analytes in samples—led the CAMI laboratory to initiate DNA profiling. The requests made by families and investigators were primarily triggered by the inconsistency between the toxicological results and the history of the use of the drugs by the victims, while by the pathologists because of the commingling of samples. In three (20%) of the 15 accidents, at least one submitted sample was misidentified or mislabeled. The low number of the accident cases requiring DNA profiling suggests that the sample-submitting agencies take extensive precautionary measures to ensure that the origin of the submitted biological samples are correctly identified. Furthermore, the present study confirms that DNA typing can be used as a tool for establishing the authenticity of the aviation biosamples, thereby their associated toxicological conclusions.