For the period FY95-FY03, each Unmanned Aerial Vehicle (UAV) accident was reviewed and classified by a series of characteristics using two approaches. The first was a variant on a methodology referred to as the Human Factors Analysis and Classification System (HFACS). The HFACS captures data for four levels of human-related failure: Unsafe acts, preconditions for unsafe acts, unsafe supervision, and organizational influences. The second analysis approach was based on the accident methodology defined in Department of the Army Pamphlet 385-40, Army accident investigation and reporting. Human causal factors are identified during this analysis and broken down into five types of failure: Individual failure, leader failure, training failure, support failure, and standards failure. Where the assignment of cause included human error, the accident data including narrative and findings were analyzed to identify specific human causal factors (e.g., high/low workload, fatigue, poor crew coordination, etc.). No single human causal factor was responsible for all accidents. However, both methods of analysis identified individual unsafe acts or failures as the most common human-related causal factor category (present in approximately 61 percent of the 18 human error related accidents).