Digital remote tower technologies rely on a video presentation for providing safety-relevant information to the tower controller. The quality of the video presentation might affect visual capabilities of the tower controller to perceive all information needed for decision making when changing from conventional to remote tower control. For investigating possible implications on safety-critical activities, we created a first baseline from a conventional tower using a verbal coding method and eye tracking data for classifying periods of visual activities by the related control task. This allows us to identify characteristics in the visual scan patterns using the out-the-window view. The presented proof-of-concept study comprises 12 approach situation samples and three tower controllers in a field study. We found group-specific and individual-specific visual scan patterns that are characteristic activities for undertaking certain control tasks. During visual search for establishing visual contact, all controllers exhibit visual scan patterns forming a triangle consisting of runway, airspace and radar. Individual characteristics were found in the timing and frequency of fixating the areas of the triangle. Also, the times fixating instruments and the out-the-window view are found to be individual characteristic. The findings provide insights into characteristics of the tower controllers that are appropriate for a later comparison with a subsequent analysis of the digital remote tower.