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Aerospace structures need excellent structural efficiency and damagetolerant behavior to avoid critical failure in presence of small defect and repeated smallloads typical of contingent loads. In order to verify the damage tolerant performance ofa rear helicopter frame, a series of tests have been performed on panel specimensrepresentative of the structure. In particular the central part of the specimens isrepresentative of the real frame structure, while the extremity (in particular theconstraint and the load application zones) are reinforced to avoid failures due tofatigue. A dedicated test equipment has been designed and built in order to apply theeffective service load. An artificial damage has been created in each panel to start acrack, and a variable load with a fixed load ratio has been applied. During the tests thepropagation of the crack has been acquired, from the starting of the crack at the twoapexes of the artificial damage, until the progressive failure of the panel involve one ormore stringers (failure of the specimen). In particular it has been monitored the passingthrough and the breaking of stringers. Moreover each specimen has been instrumentedwith several strain gauges to acquire a strain map along the specimen and during thecrack propagation. The values have been compared with a detailed FEM model withgood agreement. In particular for this work, a FEM submodel of the bolted joint,stringer and skin in the crack propagation path has been realized to obtain the crackparameter of a panel specimen.