1) Is non-conforming material identified, segregated from regular production material, and properly disposition? 2) Are procedures for controlling non-conforming materials, and for ensuing corrective action, in place and followed? 3) Do supplier’s procedures and controls for corrective action prevent reoccurrence of nonconformance? 4) Does the corrective action extend to all applicable causes of non-conformance (e.g. design, workmanship, procedures, equipment, etc.)?