This white paper addresses the issue of cost and productivity improvement in the development of safety critical software for avionics systems. Such developments follow guidelines defined by the ED-12/DO-178B document. This paper first reviews the activities traditionally performed in such developments. It then describes how individual tools can increase productivity in such context. A global optimization of the development process with the SCADE Solution is the presented, which allows much larger savings than isolated tools. Industry examples demonstrate the efficiency of this approach, and business benefits are analysed.