Modernisation of maintenance in operational condition (MCO) of defence equipment is a ministerial priority. Concerning aeronautical equipment, a major decision was taken at the end of 2006 to bring together, as from 1rst January 2008, in the one organisation, the SIAé (Aeronautical Industrial Service), all industrial support work carried out under the Ministry of Defence. This represents a big contribution to improving the performance and cost-effectiveness of aeronautical MCO.