We present a large-scale molecular dynamic simulations of a wave propagation in a bcc iron based on a N-body potential model which gives a good description of an anisotropic elasticity. A crack is embedded in a bcc iron crystal having a basic cubic orientation. We consider a central pre-existing Griffith (through) crack. The crystal is loaded on its front face and the response is detected on its opposite face. The acquired results are very important for the new NDT nano scale methods