The (numerical) solution of a rectangular crack in a perfectly conducting surface is appropriate for non-destructive testing (NDT) applications to model faults. The paper presents a direct modeling technique for determining the H and E-polarized backscattering signatures of a two-dimensional crack in a metallic surface that is suitable for inverse scattering problem. The governing field integral equations (FIE) with logarithmic and hyper singular kernels is first discretized and solved by a collocation method based on Chebyshev polynomials. By using ad hoc quadrature rules, the integral equation is then reduced to a linear system of algebraic equations. This approach does not have the size or frequency limitations of the regular techniques such as modal expansion and quasi-static manners. The results are in good agreement with the entirely numerical and non-reversible solution of a finite element method.