In this paper, the previously developed ASI-Gauss technique is applied to an aircraft impact analysis of New York World Trade Center Tower 2 (WTC2), to evaluate the structural vulnerability and behavior of the aircraft, at the horrifying scene that occurred in 2001. The ASI-Gauss technique is a modified version of the formerly developed Adaptively Shifted Integration (ASI) technique for the linear Timoshenko beam element, which computes highly accurate elasto-plastic solutions even with the minimum number of elements per member. The ASI-Gauss technique gains still higher accuracy especially in elastic range, by placing the numerical integration points of the two consecutive elements forming an elastically deformed member in such a way that stresses and strains are evaluated at the Gaussian integration points of the two-element member. From the numerical results, propagation of the shock waves resulted from the impact and high-level stresses in the structural members were observed. We could also see how the main wings of the aircraft cut through the perimeter columns and spandrels, how the debris moved through the building and to where it caused damages. Moreover, the velocity reduction of the right engine and the location from where it moved out of the building were in good agreement with the observed data.