Pull-out test results of co-cured joints were analyzed in different temperatures to understand the failure mode and strength of attaching frames and bulkheads to the fuselage skin. The differential scanning calorimetry analysis have been made for the investigation of materials of skin and rib. These definitions of glass transition temperature allowed make a choice of the testing temperatures of composite specimens. The dependence between temperature and limit load for co-cured stiffened shell under pull-out test has been obtained. Testing of specimens gave the forms of fracture in the zone of joining between rib and skin has been obtained.