The quest for airframe weight reduction results in a careful dimensioning cross section areas of structural airframe components depending on the anticipated loading. In the case of flanges of polymeric laminate spars subjected to tension such a dimensioning can be done by means of appropriate ply dropping along the spar flanges. A method for an effective calculation of the number of plies that can be cut off at the cross-section under consideration without excessive stress concentration resulted has been presented. The method takes advantage of the Linear Fracture Mechanics tools combined with simple finite element calculations. In addition, experimental data needed can be easily obtained with the use of inexpensive specimens that are simple for manufacturing and testing.