Predicting crack locations in metals (IMAGE) Johns Hopkins University Caption This is a NTSB photograph of a cracked metal disk from an airline engine caused by the type of metal fatigue that the new method would be able to predict long before a crack ever appears. Credit NTSB Usage Restrictions Credit: NTSB License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.