Southwest engine fan blade broke off mid-flight last month

A fan blade on a jet engine snapped off a Southwest plane last month in a violent failure that sent debris slamming into the plane, according to a preliminary investigative report released Monday.<br/>Investigators with the US NTSB found evidence of a crack “consistent” with metal fatigue in the titanium-alloy blade, it said in a statement released on the agency’s website. The Boeing 737-700 was forced to make an emergency landing in Pensacola, Florida, Aug. 27 after parts of the left engine broke apart, damaging the fuselage, wing and tail. The plane lost cabin pressure and passengers Tweeted pictures of themselves with oxygen masks on. While no one was hurt on the flight from New Orleans to Orlando, Florida, some of the 99 passengers aboard reported on social media that the diversion was harrowing as they looked outside and saw the air intake known as a cowling had been ripped loose, exposing the front of the engine. The five crew members also weren’t hurt. The CFM56 engine was built by CFM International Inc., a joint venture between General Electric Co. and Safran SA. The NTSB has not determined the cause of the failure. An unidentified shard put a 5-by-16-inch (13-by-41-centimeter) gash in the side of the plane above the wing, according to investigators. The cabin leaked air and lost pressure after the failure, though the NTSB said no metal from the engine pierced the cabin and no debris was found within the plane. NTSB investigators view so-called “uncontained” failures seriously because they can fling heavy metal parts into fuel lines, electronics and the passenger compartment. And under requirements in the US and other nations, it’s never supposed to happen.<br/>