In brief
The National Transportation Safety Board (NTSB) has indicated that Boeing downplayed the severity of prior warnings regarding critical engine mount failures in MD-11 aircraft. This revelation comes in the wake of a UPS cargo plane crash in 2025, which resulted in 15 deaths, highlighting ongoing safety concerns for older aircraft still in operation. Investigators are focusing on the failures of the spherical bearing race that played a crucial role in the incident.
Boeing warned plane owners in 2011 about a broken part that contributed to a UPS plane crash that killed 15 last year, but at that point, the plane manufacturer didn’t believe it threatened safety, the National Transportation Safety Board said Wednesday.
The UPS plane crashed in November 2025 shortly after taking off in Louisville, Kentucky, when the left engine flew off the wing as the plane rolled down the runway.
The NTSB stated Wednesday that Boeing had documented in 2011 that there had been four previous failures of a part that helps secure the MD-11’s engines to the wings of three different planes. However, Boeing “determined it would not result in a safety of flight condition.” These planes were built by McDonnell Douglas, which Boeing later acquired.
Investigators discovered cracks in some of the parts that held the engine to the wing, raising questions about the adequacy of the maintenance schedule. The last inspection of those key engine mount parts was in October 2021, with another detailed examination not scheduled for approximately 7,000 more flights.
This incident recalls a 1979 crash of an American Airlines DC-10 in Chicago, where the left engine detached during takeoff, resulting in 273 fatalities. The DC-10 is the predecessor of the MD-11.
Former FAA and NTSB investigator Jeff Guzzetti questioned Boeing’s decision not to classify the issues recognized in the 1980 McDonnell Douglas service bulletin as a “safety of flight condition.” He emphasized the necessity for an efficient maintenance schedule that addresses such critical components.
Investigation reports showed that the failed part was broken into two pieces post-crash, and the failure remained a significant focal point in the ongoing investigation. Both Boeing and UPS expressed condolences to the families affected by the tragedy.
The MD-11, operational yet outdated, has faced increasing scrutiny, with civilians and regulatory bodies demanding a reevaluation of older aircraft still in cargo service. Following the crash, all MD-11s and related DC-10s have been grounded.
