Boeing Co. warned plane owners in 2011 about a broken part that contributed to the crash of a UPS plane that killed 15 people last year, but at that point the plane’s manufacturer didn’t believe it threatened safety, the National Transportation Safety Board said Wednesday.
the The UPS plane crashed In November 2025, shortly after takeoff in Louisville, Kentucky, when the plane was launched The left engine flew off the wing As the plane rolled onto the runway. Three pilots On the plane bound for Hawaii they were killed along with 12 other people On the ground near Muhammad Ali International Airport in Louisville.
The NTSB said Wednesday that Boeing documented in 2011 that there were four previous failures of a part that helps secure the MD-11 engines to the wings on three different planes, but at that point the plane manufacturer decided that would not result in safe flight condition. These aircraft were actually manufactured by McDonnell Douglas, which was later acquired by Boeing.
NTSB investigators previously told I found the cracks In some parts that attach the engine to the wing. These cracks were not discovered during the regular maintenance conducted on the plane, which raised questions about the adequacy of the maintenance schedule. The last time major engine parts were closely inspected was in October 2021, and the plane was not scheduled to undergo another detailed inspection for nearly 7,000 more takeoffs and landings.
It’s not clear when cracks began to appear in the parts that helped secure the engine to the wing, but the incident is reminiscent of a 1979 crash in Chicago when the left engine of an American Airlines DC-10 flew off during takeoff, killing 273 people. The DC-10 was the predecessor to the MD-11.
This earlier accident led to the grounding of 274 DC-10 aircraft worldwide. The airline’s plume was allowed to return to the sky because the NTSB determined that maintenance workers damaged the crashed plane while improperly using a forklift to reconnect the engine. This means that the accident was not due to a fatal design flaw although there have been a number of accidents involving DC-10 aircraft already.
But Jeff Guzzetti, a former accident investigator for the Federal Aviation Administration (FAA) and the National Transportation Safety Board (NTSB), said a service bulletin issued by McDonnell Douglas in 1980 identified a ball-bearing race failure as an “aviation safety condition,” so it’s surprising Boeing didn’t call it that in 2011. He said the American company had removed that plane’s engine so it could inspect that bearing.
“I think this raises questions about how serious the 2011 service letter was, and it also raises questions about how UPS combined that information and acted on it,” Guzzetti said.
Boeing’s service bulletin did not require aircraft owners to make repairs like the FAA’s airworthiness directives, nor did the agency issue such guidance.
Alan Diehl, a former federal accident investigator, said Boeing’s notice recommended replacing the bearings with a redesigned part that was less likely to fail, but still allowed operators to replace the faulty bearing with an older bearing that had been shown to be vulnerable to failure.
“As the investigation continues, the NTSB will have to address whether this service bulletin is an appropriate solution to a known problem that could have had disastrous results,” Diehl said. “The UPS accident highlights the need for increased maintenance procedures for aging airframes.”
The NTSB has not said whether there have been additional documented failures of the ball bearing race since 2011. Investigators found that part broken into two pieces after the UPS crash, and the lugs that held the part together were cracked.
Photos released by the NTSB of the plane’s Nov. 4 crash show flames erupting as the back of the engine began to separate before it flew over the wing. The wing then caught fire as the burning engine flew over it.
The factual report released Wednesday did not say what caused the engine to spin, but investigators are clearly focused on that trend failure. A final conclusion will not be reached until after the NTSB’s final report is released, which typically does not come until more than a year after the accident.
But there is no doubt that the report will be cited First lawsuit over the accident Which was filed last month and subsequent lawsuits.
The report states that there was no fire in either of the plane’s other two engines before the crash. Some experts had previously speculated that debris flying from the left engine may have damaged the engine in the tail.
Boeing, UBS and the FAA are limited in what they can say during the NTSB’s investigation, so they all declined to comment on Wednesday’s report. Both Boeing and UPS expressed their condolences to the families who lost loved ones in the accident.
“We remain deeply saddened by the Flight 2976 accident,” UPS spokesman Jim Mayer said. “Our thoughts remain with the grieving families and Louisville community, and we remain focused on recovery efforts,” Meyer said.
The 34-year-old MD-11 plane rose only 30 feet (9.1 metres) off the ground before crashing into several industrial buildings right next to the runway and generating a massive fireball that could have been explosive. Seen for miles. Dramatic videos of the crash showed the plane bursting into flames as it crashed into buildings and released a huge plume of smoke.
Airlines stopped using this type of plane commercially years ago because it was not as efficient as newer models, but it continues to fly for shipping companies such as UPS and FedEx, and a few of these planes have been modified for use in firefighting. All MD-11s in use and 10 related DC-10s were used On the ground since the accident.