International audienceThe iterative approach in the development of Human Machine Interfaces involves the validation of design choices on both aspects of design and means of interaction. In the case of complex interfaces, conduct evaluations of such choices can be very difficult and expensive. In the field of air traffic control, especially for the design of the controllers' radar display, a simulation tool for high-fidelity usage scenarios LABY has been developed to enable ergonomists and engineers to evaluate HMI solutions in a simplified and controllable environment. In this paper we present the use of LABY in three experiments realized in order to design an innovative interface for air traffic controllers