International audienceBeyond some application related to military and civilian operations [1], the major part of the financial market is related to the use of unmanned aircraft systems (UASs) by casual customers without specific training. This requires to solve a technological and legislative challenge to ensure the safety of the population regarding the use of an aeronautical system potentially near buildings and apt to fall over people on ground. For almost 10 years and even more recently, regulatory institutions at the global scale have performed a significant work to classify UAS regarding their lethal potential in a case of an impact with people on the ground [2, 3, 4, 5]. Nevertheless, the establishment of a consensus remains a challenging task given the lack of specific and exploitable experimental data on the problematic. Hence, the purpose of the study is twofold. It first aims at providing qualitative findings on the legal and scientific framework regarding the assessment of lethal injury thresholds related to UAS impacts on human-beings. Based on this framework, the study then relies on an experimental investigation. A dedicated protocol is developed in order to minimize the sources of discrepancy previously identified and in order to conduct representative impact test cases using commercially-availables UAS. The range of drones masses considered in this study is about 900 grams with respect to the open category defined by EASA