Since critical socio-technical systems include people interacting with equipments in workplaces, their intrinsic reliability problems have been concerned with both these two “actors”. Air Traffic Control (ATC) is going to be such a system in which controllers use a large number of distributed software tools to provide safety ATC services. The reliability of these services relies on the availability of the various tools. Indeed, a partial failure of a tool in use can have tragic consequences. This paper presents a multi-agent approach to this problem. We propose an agent-based decision-aided system that helps controllers in using their multiple software tools in situations where some tools are not available due to technical incidents. We build and test our system in an ATC simulation environment, thus develop an Agent-Based Simulation (ABS). Experimental work has demonstrated the significance of our system to air traffic controllers.