A Model of Human Harm from a Falling UAV: Implications for UAV Regulation

Abstract

Aviation regulatory authorities are grappling with the problem of how to balance the benefits that small Unmanned Aerial Systems (sUAS) promise to deliver with the safety of people on board manned aircraft and the safety of people on the ground. However, there is limited published analysis available to support aviation regulators deliberations or decisions.This paper is a contribution towards expanding that body of analysis, proposing a model of the human harm that could arise from an Unmanned Aerial Vehicle (UAV) falling on to people below. Harm is modelled as fatalities and skull fractures of varying degrees of severity. The model determines the maximum allowable height that is consistent with a specified safety goal.It is shown that the maximum allowable height is dependent on the kinetic energy of the UAV, and in this sense is consistent with the recent recommendations of the FAA-chartered Micro UAS Aviation Rulemaking Committee. However, it is also shown that maximum allowable heights for UAVs as small as 250g and below should be set at significantly less than 400ft AGL when flying over people.There should also be restrictions on the density of people over which UAVs are able to fly. Increasing the reliability (reducing Mean Time Between Failure) increases the density of crowds over which a UAV can safely fly, but does not alter the maximum allowable height.