Airlines flying older jets are facing tougher, more time-consuming U.S. inspections after the fuselage of a Southwest Airlines jet ruptured last week, leaving a 5-foot hole and questions about how companies and regulators will manage aircraft fatigue.
Addressing metal fatigue has become more of an issue for the industry as the life of commercial planes is extended by structural and cabin refurbishing, new engines and cockpit technology. Boeing has faced this on its older 737, or “classic” fleet. The ruptured Southwest jet was a Boeing 737-300.
“There have been issues with this in the past,” said Boeing spokesman Marc Birtel, noting that the design of the 737-300 series was changed in 1993 due to fatigue issues. He said Boeing had not seen this kind of incident since those changes were made.
The modifications were aimed at preventing large tears in the fuselage skin, like the one that occurred last Friday on the Southwest jet while it was en route from Phoenix, Arizona, to Sacramento, California, carrying 118 passengers. The plane made an emergency landing at the Yuma Marine Corps Air Station in Arizona.
Boeing engineer Paul Richter said Boeing did not expect the type of fatigue suspected in the Southwest plane to occur until much later in the jet’s life. It is 15.
A review of FAA records showed that since 2002 the agency has issued six directives regarding inspections for fuselage-related cracking involving older model 737s, including the 300, 400, and 500 series. Those models were targeted in an FAA order on Tuesday for urgent electromagnetic inspections on heavily used models made between 1994 and 2003.
A 2009 inspection order was in response to another incident involving a Southwest jet with a smaller hole in its fuselage. And Southwest paid a $7.5 million FAA fine for operating 737s without required fuselage inspections in 2006-07.
WHY SUCH A TEAR?
“We don’t expect aircraft in service today to rapidly decompress and have a situation where the airplane fuselage is ripping open,” National Transportation Safety Board (NTSB) Chairman Deborah Hersman said on Tuesday.
“We’ve seen events in the past where there was a failure. We understood the failure mechanism there. This is not the same. This is something different,” Hersman said.
“We want to understand why we saw the extent of tearing on an aircraft this size,” Hersman said.
She said the FAA was reviewing records regarding the Boeing 737-300 incident and fatigue cracks in general.
The latest FAA order requires more aggressive inspections for the 70 or so affected jets flown by Southwest, the leading U.S. carrier by passenger volume. Nearly 600 planes worldwide would be affected by the directive that was stricter than a Boeing service bulletin also issued on Tuesday.
The FAA has not indicated if it will seek more design changes. But the agency’s administrator, Randy Babbitt, told Congress on Wednesday that whatever is learned from the Southwest incident will be incorporated into any design, inspection or maintenance requirements.
Babbitt said he would ask his staff to review the FAA’s program for safety on aging aircraft to “ensure we are asking the right questions and taking full advantage of all available data.”
Near term, the new order for more inspections on heavily used older jets should not harm Southwest or other airlines.
“That doesn’t materially affect the 737s operating economics,” Teal Group analyst Richard Aboulafia said.
(Reporting by John Crawley and Karen Jacobs)
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