NTSB seeks redo of Boeing 737 NG part
Plane maker says it is fixing the engine problem that led to Southwest passenger’s death in April 2018.
The U.S. National Transportation Safety Board recommended Tuesday that the Boeing Co. 737 NG be redesigned to prevent a repeat of a fatal incident last year in which an engine part broke off in flight, something the plane maker says it is doing.
More than 7,000 so-called 737 Next Generation planes could be affected by the recommendation that the inlet to the engines be redesigned to contain parts that come loose in a failure.
The safety board issued the recommendation after a hearing Tuesday on the April 17, 2018, incident in which a woman on a Southwest
Airlines flight was partially sucked out of the plane and died.
A fan blade on an engine made by CFM International Inc. broke off, triggering the damage, the NTSB concluded.
The NTSB called on the Federal Aviation Administration to require the repair be made on new 737 NG aircraft and that it be retrofitted onto the thousands of planes in service.
“These recommendations show the way toward greater safety even when a fan-blade-out event occurs,” NTSB Chairman Robert Sumwalt said at the conclusion of the meeting.
Boeing said in an emailed statement that it is introducing enhancements to the part of the engine that failed to improve its ability to withstand a broken fan blade.
“Boeing is committed to working closely with the FAA, engine manufacturers and industry stakeholders to implement enhancements that address the NTSB’s safety recommendations,” the company said in the statement.
Southwest said in a statement that it looks forward “to reviewing the recommendations of the NTSB and continuing our work with the manufacturers to prevent this type of event from ever happening again.”
The FAA said it will “carefully review and respond to the NTSB recommendations.” Safety is the agency’s first priority, it said in the emailed statement.
Boeing shares slid as much as 2.1% after the NTSB’s comments, but recovered most of that loss. It ended the day down 0.7%.
The NTSB did not ask for changes on other aircraft and engine combinations, but it asked for improvement on how the structure at the front of the engine — a curved surface that provides a smooth flow of air into the power plants — is designed in the future.
The NTSB also urged the European Aviation Safety Agency to adopt the suggested improvements. Although the FAA has no legal authority outside the United States, other nations typically follow its lead.
The NG model is a predecessor to Boeing’s 737 Max, which has been grounded since March after a pair of deadly crashes.
At least part of the reason the April 2018 engine failure caused so much damage is the unusual shape of the structure outside the 737 NG engine. Instead of being circular, as is the case on most models, the NG is flattened on the bottom so the engine can fit on its relatively low wings. It was on that f lat section that a hunk of metal broke loose and was flung into the side of the plane, where it struck a window, the NTSB said.
CFM, a joint venture between General Electric Co. and France’s Safran, said it developed the engine’s design in close collaboration with Boeing. “We will continue to strictly comply with regulatory requirements, including any changes that might be adopted as a result of NTSB’s recommendations,” the company said in an emailed statement.
Engines are required to be encased in an armored sleeve to prevent debris in a failure from striking the plane, but the structure that hit the window on the Southwest plane was designed by Boeing and was in front of the protected area. Such failures weren’t anticipated during certification and testing, the NTSB said.
The fractured fan blade started a chain reaction that led a hunk of metal to fly off the jet engine, shatter a window on the plane and trigger an explosive decompression.
The air rushing out of the 737-700 at about 32,500 feet partially sucked 43-year-old Jennifer Riordan through the window, killing her despite other passengers’ attempts to pull her back.