Damage tolerance assumes the existence of initial flaws in the structure and the structure is designed to retain adequate residual strength until damage is detected and repaired during planned maintenance periods. BEASY's crack growth simulation tools can be used to support damage tolerant design by supplying the SIF data for initial flaw sizes to determine if these cracks would grow (K < Kth). BEASY is also used to determine the rate of crack growth and can be used to show that initial damage will grow at a stable rate and cracks will not reach critical sizes (K > Kc) before scheduled inspections.