Power systems contingency analysis is an important issue for electric power system operators. This paper performs branch outage simulation based contingency screening using a bounded network approach. Local constrained optimization problem representing the branch outage phenomena is solved by the gravitational search algorithm. The proposed method is applied to IEEE 14, 30, 57, and 118 Bus Test systems and its performance from the point of capturing violations is evaluated. In addition, false alarms and the computational accuracy of the proposed method are also analyzed by using scattering diagrams. Finally, the proposed gravitational search based contingency screening is compared with full AC load flow solutions from the point of computational speed. Copyright (C) 2012 Praise Worthy Prize S.r.l. - All rights reserved.