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Analysis by-product is becoming less and less relevant to characterizing the productive organization of industrial clusters. Transverse relationships between activity branches depend on the circulation of complementary skills and impel cognitive strategies between firms in various sectors. In Toulouse, the activities of on-board systems grew initially according to a sectoral logic before being the object of skills transversality and expertise shared between several industrial sectors (aeronautics, the space sector, terrestrial transportation electronics, etc.). This productive system was then consolidated by positive externalities such as computing services subcontracting and sharing, collaboration between industries and local research institutes on critical computing systems, and staff movement within the regional labor market. To that was added strong institutional action represented by the addition of an on-board systems sector to the aeronautical and space competitive cluster common to the Midi-Pyrénées and Aquitaine regions of France. In the case of Toulouse, the activities of on-board systems and their multisector dimension define an organizational principle based on local skills system.