Overloading and other service abuses. Design shortcomings. Material imperfections due to faulty processing or fabrication. Environment-material interactions. To determine the cause of the failures, the following method was used: Appearance – an illustration and brief description of a component that has failed due to a specific cause. Damaging Action – what actually damaged the component under the conditions which were present? Possible Causes – a listing of those factors capable of creating the particular damaging action. Corrective Action – the action that should be taken to correct the cause of failure.