Modeling Operational Risk to Improve Reliability of Unmanned Aerial Vehicles

As Uncrewed Aerial Vehicle systems (UAVs) become more common and useful in public airspaces, this technology and its operation must be highly reliable to reduce risk to the general public. The objective of the present work is to improve the chances of mission success by analyzing and controlling the risk of UAV missions during different operational phases. Given the lack of reliability models for UAVs, we employ a systems reliability modeling methodology based on task decomposition and conditional risk analysis of each activity during a mission. The various risks involved in a specific mission activity are identified using Hazop techniques and Failure Modes and Effects Analysis (FMEA), along with the stopping conditions necessary to limit risks to an acceptable level. Different parts of a mission have different risk priorities, and the internal and external causes of failures of each activity are identified, described, and ranked according to their impact and uncertainties. This work constitutes the first phase of a broader research project. The risks of the UAV mission are modeled, after which it is verified by subject matter experts prior to implementing controls in an industrial case study.