Before revision: Widespread fatigue damage (WFD) in a structure is characterised by the simultaneous presence of cracks at multiple points, that are of sufficient size and density such that, the structure will no longer meet its damage tolerance requirement and could failAmos W Hoggard and Stephen R Johnson,"Boeing WFD Rule" aero_2012q4_article2" .
After revision: Widespread fatigue damage (WFD) in a structure is characterised by the simultaneous presence of cracks at multiple points, that are of sufficient size and density such that, the structure will no longer meet its damage tolerance requirement and could fail.Amos W Hoggard and Stephen R Johnson,"Boeing WFD Rule" aero_2012q4_article2"