Federal safety investigators opened two days of hearings Tuesday to examine why the engine flew off a UPS cargo plane last year, causing a crash that killed 15 people, and why Boeing didn’t address an underlying flaw sooner.
The engine separated from the MD-11's wing as it accelerated down the runway at Louisville’s Muhammad Ali International Airport in November. The crash killed three pilots on the plane and 12 people on the ground. More were injured.
“Please know: Your loved ones are the reason we’re here. We want to find out what happened,” Jennifer Homendy, chair of the National Transportation Safety Board, said as she addressed families during her opening remarks.
Separately, more details emerged as the NTSB released more than 2,000 pages of documents related to the disaster. The ill-fated plane was pressed into service after a fuel leak sidelined the original plane, investigators said, and the flight crew shared good-natured banter with the maintenance team during the second pre-flight inspection about “meeting again” so soon.
The hearings at the NTSB headquarters in Washington involve rounds of questions and answers among board members, investigators, and representatives of Boeing, UPS, the mechanics' union and other parties. The NTSB's final report likely won’t be ready until more than a year after the crash because it will look at every potential factor.
Here's what you should know:
The crash
The UPS plane, which was headed for Hawaii loaded with packages and fuel, had barely left the ground and cleared the airport fence when it crashed into several nearby Louisville businesses and created a massive fireball.
Dramatic photos the NTSB released after the crash showed the engine detaching and flying up and over the wing as flames erupted on the wing. The final images show the plane ablaze as it briefly gets airborne, leaving behind trails of smoke.
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All MD-11s and DC-10s, a predecessor aircraft, were grounded after the crash. NTSB investigators said Tuesday that similar part flaws were found in three other UPS planes and a DC-10.
The Louisville disaster was reminiscent of a 1979 crash in Chicago involving a DC-10. The left engine also fell off in that crash, which killed 273 people and led to the worldwide grounding of 274 DC-10s.
The airliner returned to the skies because the NTSB determined that maintenance workers had damaged the plane that crashed while improperly using a forklift to reattach the engine. That meant the crash wasn’t caused by a fatal design flaw even though there had already been a number of accidents involving DC-10s.
But even at that point, the plane's manufacturer, McDonnell Douglas, raised concerns about the spherical bearing that helps hold the engines to the wings. McDonnell Douglas later merged with Boeing.
Past problems with these planes
The NTSB said shortly after the Louisville crash that investigators had found cracks in some of the parts that held the engine to the wing. Those cracks hadn’t been caught in regular maintenance done on the plane, which raised questions about the adequacy of the maintenance schedule. The last time those key engine mount parts were examined closely was in October 2021, and the plane wasn’t due for another detailed inspection for roughly 7,000 more takeoffs and landings.
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Boeing had documented in 2011 there were four previous failures on three different planes of a part that helps secure the MD-11’s engines to the wings, but at that point the plane manufacturer “determined it would not result in a safety of flight condition.”
The service bulletin that Boeing issued didn’t require plane owners to make repairs like an FAA airworthiness directive would, and the agency didn’t issue such a directive. At that point, Boeing just recommended replacing the bearings with a redesigned part that was less likely to fail.
MD-11 planes flying again
Some MD-11s, a workhorse of the cargo fleet, are now back in the air after the FAA approved Boeing's plan to replace the spherical bearing on each aircraft and increase inspections.
FedEx resumed using the planes to deliver packages on May 10, but UPS has said it plans to retire its fleet of MD-11s. Western Global also uses MD-11s but hasn’t said what it plans to do.
Some experts speculated after the crash that the MD-11s might never fly again if the repair proved to be more expensive that it was worth in these older planes. But Boeing said it found a way to address the safety concerns simply by replacing the bearing and stepping up inspections.
