A vortex-lattice numerical scheme that uses a novel decambering technique to predict post-stall aerodynamic characteristics is used to study the aerodynamics of tandem Cessna 172 aircrafts flying in echelon formation. Results like CL- α from the current method are compared with experiment. Additional results like section Cldistributions over wing spans, CM- α and CLW- αtw(i.e. CLof the leading aircraft for different angles of attack of the trailing aircraft) and analysis for (-) ve y-offset, which are available only from the current numerical method are reported that supplement the experimental results. Detailed post-stall numerical analysis and the effect of chord-wise, span-wise and vertical offsets on the aerodynamics of the formation are also reported. © 2014, American Institute of Aeronautics and Astronautics Inc. All rights reserved.