It is not the fuel lines, per se, in which cracks have been detected, but seperate "flow liners" (relatively thin cylindirical liners manufactured from Inco 718 or 321 SS sheet material) used inside the fuel lines to smooth what would otherwise be overly turbulent flow in convoluted wall "bellows" sections of those lines. The concern is that if these crack were to propogate, that these liners might be ingested...
Does anyone have information regarding the "Unprecedented welding" mentioned in the article? I assume it means the flow liners were weld repaired.