On October 28, 2016 American Airlines flight 383 experienced a right engine uncontained failure and subsequent fire during takeoff ground roll at Chicago O’Hare International Airport. An on-scene NTSB investigation determined that the failure was caused by the second-stage turbine disk, which had ruptured into two pieces. One piece penetrated the inboard section of the right wing, severed the main engine fuel feed line, traveled up and over the fuselage, and landed about 2,935 feet away. The other piece impacted the runway and fractured into several smaller pieces. The NTSB Materials Lab examination of the disk pieces determined that the alloy 718 disk had failed in low-cycle fatigue initiating at an internal anomaly known as a dirty white spot. This presentation will discuss the failure analysis of the anomaly and its cause, inspection procedures for the billet, how the anomaly went undetected, and the prospect of enhanced inspection procedures.