(NTSB) investigators, aided by GE, are analyzing remains from the 1998-built No.2 (right) engine, which the manufacturer describes as containing “very high-cycle discs.” The NTSB, which reported Oct. 29 that at that stage 90% of the disk had been recovered, is focusing on identifying potential faults with the metallurgy, machining and forging of the part, as well as the specific bill of materials of the failed engine.
It's not too soon to already know the answers to above , but the how and why take a lot longer and only then the what to do as a result follows.