Southwest engine fan blade showed signs consistent with metal fatigue: NTSB

Federal investigators Thursday said the engine fan blade that broke apart during a Southwest Airlines flight last month showed signs consistent with metal fatigue, as inspectors probe the first passenger fatality on a US airline in nearly a decade. The accident touched off a scramble to inspect similar equipment. US regulators this week broadened a directive to check the fan blades in hundreds of engines similar to the one that blew apart. The identification of metal fatigue, the degradation of a metal's structural integrity over repeated use, could necessitate more frequent and more comprehensive inspections of these parts. The NTSB's investigation is ongoing to determine how long it takes for fan blades begin to show signs of fatigue and whether current inspection measures can effectively detect cracks. <br/>