This paper presents the preliminary work done for a ight validation process for several existing and under-development metrics-driven adaptive flight control methods. This is key element in the larger NASA Intelligent Resilient Aircraft (IRAC) program, which seeks to increase overall aircraft safety through improvements in stability, maneuverability, and probability of safe landing under adverse conditions - including aircraft damage. This paper focuses on development of the simulation environment, which is necessary to test and develop the control architectures before flight testing. It proposes a fully nonlinear six degree of freedom dynamic model of the vehicle that captures qualitatively severe damage. Example damage cases are partial loss of wing surface, loss of control effectivenes, engine failures etc. This affects the dynamic model on three apsects: shift of center of gravity, change of aerodynamic coefficients and reduced controllability of the vehicle. We propose a model which structure combines the different aerodynamic contributions of the surfaces to capture modifications of the dynamics due to damage.