A new NTSB report recommends the FAA require Boeing to redesign the structure that holds the plane's engine, as well as install it on all new 737 NG planes.

By Alison Fox
November 20, 2019
Boarding1Now/Getty Images

Boeing will likely have to redesign the engine covers on its 737 next-generation planes and airlines will have to retrofit their planes to match following the Southwest accident last year according to a new report from the National Transportation Safety Board.

According to the NTSB, probable cause for the April 2018 accident — that killed one woman after an engine malfunctioned midflight and a piece of shrapnel broke a window. — on Southwest Flight 1380 was a fan blade that fractured due to “a fatigue crack,” causing it to break off and destroy the fan cowl, or the structure that holds the plane’s engine.

The NTSB’s report on the accident recommended the FAA require Boeing to redesign the fan cowl structure as well as install it on all new 737 NG planes. The board also recommended the FAA require operators of the planes to retrofit their aircraft with the redesigned fan cowl structure.

“This accident demonstrates that a fan blade can fail and release differently than that observed during engine certification testing and accounted for in airframe structural analyses,” NTSB Chairman Robert Sumwalt said in a statement. “It is important to go beyond routine examination of fan blades; the structural integrity of the engine nacelle components for various airframe and engine combinations needs to be ensured.”

“This accident demonstrates that a fan blade can fail and release differently than that observed during engine certification testing and accounted for in airframe structural analyses,” NTSB Chairman Robert Sumwalt said. “It is important to go beyond routine examination of fan blades; the structural integrity of the engine nacelle components for various airframe and engine combinations needs to be ensured.”

In a statement from Boeing, the company said that “all 737 NGs are safe to continue operating normally as the issue is completely mitigated by the fan blade inspections” but added that “Boeing is working on the design enhancements to fully address the safety recommendation from the NTSB."

Those changes will be implemented on existing 737 NG’s “over the longer term.”

There are several thousand Boeing 737 NG’s currently in service, and Southwest has more than 700, according to USA TODAY. Following the accident last year, Southwest was forced to cancel up to 40 flights per day to complete emergency engine inspections.

This is the latest blow to Boeing, whose 737 MAX planes have been grounded since March all over the world following two fatal accidents that killed 346 people.

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