Approved for public release, distribution is unlimited / 235 Class A Navy and Marine (Naval) aviation mishaps involving aircrew error between FY 90 and FY 98 are analyzed for the possibility of being weather related. In addition to determining the overall role of weather, weather related mishaps are compared to aircraft category, mishap characteristic, the Naval Safety Center human factors (HFACS) taxonomy, and flight phase. In addition, weather related mishap trends have been analyzed. Results show 19% of mishaps involving aircrew error are weather related with helicopter category and controlled flight into terrain (CFIT) mishap characteristic having the largest percent of weather related mishaps for their respective groupings. Visibility related weather elements account for over half of all weather related mishaps, and nearly two-thirds of all weather related mishaps were judged to be preventable with a perfect weather forecast believed by aircrew. These and other findings are presented to develop intervention strategies for reducing the number of weather related flight mishaps (FMs) per year. / Lieutenant Commander, United States Navy