The disc wasn’t totally GE’s fault. The subcontractor that made the raw material was to melt the material 3 times before pouring a blank. After the machining process they either X-ray the part or check it with ultrasound. Either way a serious crack would have been detected. Actually any crack would have been detected. Since the part was only melted twice it allowed for microscopic particles to exist. And after 16 years of almost constant running the normal vibration caused a very fine particle to become a catastrophic crack. After the thousands of CFM-6’s built. The crack appeared on 3 engines. Unfortunately the first was found the wrong way. The contractor had to pay a healthy portion of the costs, which unfortunately doesn’t heal the dead and injured. I worked for GE and handled many of the found parts during our investigations.