This paper deals with the conceptual design of a decision aid function for restoration (DAFFOR) of transmission networks after major black-outs, and in particular with real time considerations. Some important characteristics of the proposed DAFFOR are: (a) capability of taking into account the dynamic evolution of the network state, due to either a control action or an unforeseen event; (b) interactive mode, which permits users to request a validation of their own suggestion; (c) coupling with an internal dynamic simulator which is solicited to validate any suggestion. At present, the DAFFOR is coupled with the French National Utility Operator Training Simulator (EDF OTS). After intensive testing within the OTS environment, the operational version of the DAFFOR will be developed