time-domain surface integral equation approach based on the electric field formulation is utilized to calculate the transient scattering from real complex structures composed of both conducting and dielectric bodies. The solution method is based on the method of moments and involves the modeling of an arbitrary shaped structure in conjunction with the triangular patch basis functions. An implicit method is described to solve the coupled integral equations derived utilizing the equivalence principle directly in the time domain, and the usual late time instabilities associated with the time domain integral equations are avoided by using this implicit scheme. The structure used in this paper is an aircraft that has many different shaped triangular patches to make close enough to the real aircraft. Mathematical and numerical steps are presented along with representative numerical results.