Flight simulators have been part of aviation history since its beginning. With the development of modern aeronautics industry, flight simulators have gained an important place and the industry devoted to their manufacture has become significant. In the case of transportation aircraft, accurate mathematical models based on extensive experimental data have been developed by their manufacturers to optimise their aerodynamic and propulsive characteristics and to design efficient flight control systems. However, in the case of small general aviation aircraft this kind of knowledge is not commonly available and the design of accurate flight simulators can result in a tedious try and modify process until the simulator presents a qualitative behaviour close to the one of the real aircraft. This communication proposes through the use of neural networks a method to perform a direct estimation of the aerodynamic forces acting on aircraft. Artificial Neural networks appear to be an appropriate numerical technique to achieve the mapping of these continuous relationships and detailed aerodynamics and thrust models should become no more mandatory to produce accurate flight simulation software. © 2005 IEEE. 168172Jategaonkar, R., Flight vehicule system identification in time domain (2003) DINCON03, , Courses notes, São José dos CamposRaisinghani, S.C., Gosh, A.K., Parameter estimation of an aeroelastic aircraft using neural networks (2000) Sadhanã, 25 (2 PART), pp. 181-191. , AprilSteven, B.L., Lewis, F.L., (1992) Aircraft Control and Simulation, , John Wiley & Sons, IncHaykin, S., (1994) Neural Networks: A Comprehensive Foundation, , McMillan, New YorkCybenko, G., Approximation by superpositions of a sigmoïd function (1989) Mathematics of Control, Signals and Systems, 2, pp. 303-314Shazad, M., Slama, J.G., Mora-Camino, F., A new approach for the automation of relative guidance of aircraft (1999) 13 th International Conference on Systems Engineering, , Las Vegas, USAHagan, M.T., Menhaj, M.B., Training feedforward networks with marquardt algorithm (1994) IEEE Transactions on Neural Networks, 5 (6)Freeman, J.A., Skapura, D.M., (1997) Neural Networks Algorithms, Applications and Programming Techniques, , Addison-Wesley, New-York