The Southwest Airlines plane that caused an in-flight nightmare Friday when a five-foot hole opened up in its passenger cabin had showed signs of structural fatigue at least one year ago, federal records show. In a March 2010 inspection, the Boeing 737 showed 10 instances of cracking in its frame and an additional 11 instances of damaged stringer clips, which hold together the plane’s skin. On Sunday, federal investigators examine the tear that brought the plane down Friday and found “evidence of widespread cracking.” In the meantime, Southwest has grounded 79 planes for inspection and canceled as many as 600 flights.
