The paper aims at highlighting the links between simulator training and direct training in the case of initial training for military helicopter pilots. The issue is considered from the perspective of the instructor’s activity. Pilot students are severely selected and their training is strongly framed, both through the civil aviation norms and by the high expectations vis-à-vis military pilots. It includes simulation sessions and real flights, in order that students master the maneuvers which are the core of using helicopter as an instrument, a means among others for military missions. Instructors intervene in both types of training. Their task is itself strictly framed: organization of training tasks, precise guidelines for exercises and sessions management, including evaluation. Professional Didactics (Pastré, Mayen, & Vergnaud, 2006) provides a theoretical framework for studying the role of instructors in coordinating students’ training. The notion of scaffolding – transposed from Bruner’s notion of tutoring (Wood, Bruner, & Ross, 1976) – offers an entry on their didactical mediation. Professional documents and research productions in the aviation or driving domains are used for identifying actual knowledge and open questions about training. Their analyses orient the study developed in the last part of the paper about the role played by instructors in relating students’ competences acquired in the simulator and on the field. The personal expertise of the second author - as a pilot, a trainer and a monitors’ trainer - is deeply involved for tackling this issue. The conclusion discusses the relevance domain for such an analysis of trainers’ activity, when work implies sensori-motor competences, involves intrinsic complexity of the interactions between commands, where tasks are highly proceduralised but situations openness calls for developing anticipation competences.