During the usage phase, a technical product system is in permanent interaction with its environment. This interaction can lead to failures that significantly endanger the safety of the user and negatively affect the quality and reliability of the product. Conventional methods of failure analysis focus on the technical product system. The interaction of the product with its environment in the usage phase is not sufficiently considered, resulting in undetected potential failures of the product that lead to complaints. For this purpose, a methodology for failure identification is developed, which is continuously improved through product usage scenarios. The use cases are modelled according to a systems engineering approach with four views. The linking of the product system, physical effects, events and environmental factors enable the analysis of fault chains. These four parameters are subject to great complexity and must be systematically analysed using databases and expert knowledge. The scenarios are continuously updated by field data and complaints. The new approach can identify potential failures in a more systematic and holistic way. Complaints provide direct input on the scenarios. Unknown, previously unrecognized events can be systematically identified through continuous improvement. The complexity of the relationship between the product system and its environmental factors can thus be adequately taken into account in product development. Keywords: failure analysis, methodology, product development, systems engineering, scenario analysis, scenario improvement, environmental factors, product environment, continuous improvement.