Augmented reality (AR) technologies start to be mature enough to be used in industrial work settings. However, human factors and ergonomics (HFE) and safety issues have not been considered thoroughly yet. The purpose of this study was to identify what kind of postures users adopt when using a tablet based AR system during a maintenance task. In addition, safety, user experience and user acceptance were studied. Results indicate that the participants adopted varying kind of working postures with the AR system, but none of the postures were severe for the well-being. User experience was positive and user acceptance on a good level. The participants saw some safety concerns related to using the AR system but were mainly concerned if the tablet could be used in the harsh maintenance environments. The findings of this study can be used to improve HFE and safety of AR systems in industrial settings.