In this paper we argue that the predominant modelsof Situation Awareness (SA) are inadequate for thestudy of systems operated by teams. The reason forthis is that these models are based on mentalisticassumptions focusing almost exclusively onindividuals. We suggest that, to study the control ofdynamic systems, it is necessary to shift the unit ofanalysis from the individual to the whole cognitivesystem comprising a team of people as well as theartefacts which they use. Thus, our vantage point isthe theoretical framework of distributed cognition.Through two field studies we try to demonstrate howteam situation awareness is actively constructed viathe communicative practices which the team uses inits work.