  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.
