The uncontained left engine failure on an August 27 Southwest Airlines flight from New Orleans to Orlando was likely initiated by a fan blade that broke off because of metal fatigue, according to a September 12 investigative update by the US National Transportation Safety Board (NTSB).
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The jet is now under fix but no date has been given for when it will re-enter service. The crew landed the plane safely in Singapore.
The NTSB said initial laboratory findings indicated that an area of the titanium-alloy blade stub about one inch long and one-fifth of an inch deep showed signs “consistent with fatigue crack growth”.
Investigators did not say why they suspect the fan blade broke loose.
Investigators with the National Transportation Safety Board said they found a hole five inches by 16 inches in the left fuselage. A manufacturing defect in the engine, made by United Technologies’ Pratt & Whitney, should have been detected by airline maintenance workers performing routine inspections, the NTSB investigation concluded. The engine was made by West Chester-based CFM International, the joint venture of Evendale-based GE Aviation and Safran of France. Jet engines are designed so that a failure is “contained” and parts can’t be flung into the passenger compartment or any control surfaces or equipment of a plane.
“Given the experience we have had with this aircraft and this engine, the odds of a systemic problem are basically nil”, Aboulafia said.
The damage caused cabin depressurisation and the flight diverted to Pensacola. No one was injured.
NTSB said the initial investigation found that the left engine inlet separated from the engine during the flight.
The agency also said that during the accident engine debris impacted the plane’s side to create the hole above the left wing.
“GE and Safran continue to assist the NTSB in its investigation”, GE spokesman Rick Kennedy told Bloomberg News.
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John Cox, a former pilot and now an aviation-safety consultant, said the NTSB will probably focus on how long the fan blade that broke off had been cracked and why Southwest didn’t discover metal fatigue during maintenance checks. AP material published by LongIsland.com, is done so with explicit permission. This includes the preparation of derivative works of, or the incorporation of such content into other works. Please see our terms of service for more information.
