Southwest Airlines B737 engine explosion linked to fan blade fatigue
19 April 2018
An engine explosion on a Boeing 737 flying from New York to Dallas on April 17 killed a passenger when shrapnel from the blast penetrated the fuselage. Southwest Airlines Flight 1380, with 149 people on board, was forced to make an emergency landing in Philadelphia.
Southwest B737-700 - Image: Wikimedia Commons
Escaping air from the punctured pressurised cabin sucked the passenger out of the fuselage, although she was held by other passengers and pulled back in. Despite her rescue, the passenger's head injuries were so severe she did not survive.
Investigators said there was a fault with the engine's fan blades which caused the front of one of the aircraft’s two engines to disintegrate. An initial investigation found evidence of metal fatigue where the fan blade had broken off, according to the US National Transportation Safety Board (NTSB).
A similar engine fault in a CFM56-7B engine on a Southwest aircraft was reported in 2016 over Florida, although there were no casualties in that incident.
Fan blades that have undergone a certain number of flights will have to be given ultrasonic tests, the Federal Aviation Administration (FAA) said, adding that an Airworthiness Directive would be issued in the next two weeks requiring inspections of a large number of that type of engine.
The CFM56-7B engine is in use on more than 8,000 Boeing 737 planes worldwide, the manufacturer said.
NTSB chairman Robert Sumwalt told reporters that a fan blade had broken off due to metal fatigue and that a second fracture had been recorded about halfway along its length.
He also said a casing on the engine was meant to contain any parts that came loose but, due to the force of the disintegration, metal was able to penetrate the fuselage.