Designers are often tempted to assume that the operators are always available in case of an exceptional event, and that they can handle the situation. Indeed, this is typically the case.
However, it might happen that just at the time of the incidence the operator is away, disrupted by an annoying phone call, troubleshooting an unrelated problem, or busy doing something else, and therefore fails to notice the event, or its significance.
The operator's mental activities involved in the operation under hazard is described in the model of problem solving .... The corresponding operator's tasks are described here:
Often, the response to the event is not adequate in emergency (see " ;irony of automation").
Updated on 26 May 2016.