The article examines methods for facilitating the operation of socio-technical systems. Operational failure is due to diversion from procedures and situations defining normal activity. Sources of operational failure include triggers, exceptions, and uncoordinated activity. The article presents a model comprising three layers of the visibility of operational failure: incidents, errors, and accidents. The principles and methods discussed here focus on the need to maintain coordinated activity, and to mitigate the risks of exceptions. The protection from failure should be based on generic rules describing normal situations and activity. A model of HSI proposed here consists of interaction cycles, each comprising a supervisor, controllers, and service processes. Human decisions should rely on forecast of the system behavior in response to optional decisions. The preview information may be obtained by behavioral twins.