The topic of the thesis is framed within the activities of a project whose purpose is to convert a civil platform into a multi-role aircraft capable of long range maritime patrol mission, as well as anti-submarine and anti-surface warfare missions. Design and modification activities will require to build a mathematical model of both the unmodified and modified aircraft that will be used to execute an analysis of the performances. Within this context the main objective is to build a mathematical model of the aerodynamic characteristics and a mathematical model of the engines in order to be used to execute performance analysis of both the unmodified and modified aircraft Here are the milestones of the work: • CFD: – Management of A/C CAD models and mesh creation.