Boeing had issued a warning to aircraft owners back in 2011 regarding a faulty part, which has been linked to a recent UPS plane crash that resulted in 15 fatalities last year. However, at that time, Boeing did not consider it a safety concern, according to a report from the National Transportation Safety Board (NTSB).
The accident occurred shortly after takeoff from Louisville in November 2025, when the left engine detached from the wing as the aircraft veered off the runway.
The NTSB revealed that before the crash, Boeing had recorded four failures involving the component that attaches the MD-11’s engine to the wing, but they concluded that it posed no safety risks for flight operations back in 2011.
While the NTSB is unclear on whether more issues with the spherical bearing race have surfaced since then, investigators determined that the UPS part broke completely during the crash, with visible cracks in the lugs that held it together.
Images from the crash scene show the rear of the engine beginning to detach and flames igniting before the engine was flung onto the wing, which quickly caught fire.
The tragic event claimed the lives of three pilots and twelve individuals on the ground around Louisville’s Muhammad Ali International Airport.
As of this report, the cause of the engine explosion remains unspecified, with the NTSB expected to release a comprehensive final report, usually taking a year or more to complete.
Responses from Boeing, UPS, and the Federal Aviation Administration regarding the updated findings have not yet been made, which is typical as parties involved in such incidents often refrain from comment until investigations conclude.
The NTSB had previously indicated that cracks were found in engine mount parts that were not detected during routine maintenance checks, raising concerns about whether the maintenance practices were adequate. The components in question last underwent inspection in October 2021 and were not due for another check for approximately 7,000 further flights.
The MD-11, which was 34 years old, only managed to fly 30 feet above ground level before it crashed into nearby industrial buildings, creating a massive fireball that was visible from great distances. Eyewitness videos captured the dramatic moment of the crash as the plane collided with the building, engulfing it in flames and producing thick clouds of smoke.
Due to the inefficiency of older aircraft, MD-11s have been phased out of commercial service, although they are still used by cargo carriers like UPS and FedEx, and some have even been adapted for firefighting roles. Following this incident, all MD-11 and related DC-10 aircraft currently in operation have been grounded.
It’s uncertain when exactly the cracks on the engine-mount components first appeared, but the situation echoes a tragic incident in 1979 when an American Airlines DC-10 lost its left engine during takeoff in Chicago, resulting in 273 deaths. The MD-11 is a successor to the DC-10.
Following the earlier crash, 274 DC-10s were grounded worldwide. It was later determined that improper maintenance involving a forklift had caused damage to the plane during engine reinstallation, meaning that a design flaw wasn’t to blame, though the DC-10 had a history of similar accidents.
