By Drew FitzGerald

Federal investigators probing a fatal jet crash in Louisville, Ky., are reviewing how Boeing responded to past failures of certain components on its McDonnell Douglas aircraft.

The National Transportation Safety Board said Wednesday that an examination of the wreckage of United Parcel Service Flight 2976 found a bearing piece with signs of fatigue cracking and stress. The bearing was part of an assembly linking the MD-11 freighter's left engine to its wing.

More than a decade ago, Boeing sent a service letter to MD-11 operators reporting four failures involving a similar type of bearing assembly, according to the NTSB. The failures were identified on three planes.

Boeing said in the 2011 service letter that the failure "would not result in a safety of flight condition." The company discussed a new configuration for the bearing assembly in the letter, according to the NTSB, but the plane maker didn't prohibit installations with the prior configuration.

The safety board said it would review how proposed inspections discussed in the letter were incorporated into Boeing's documents for MD-11 maintenance crews.

A Boeing spokesman said the company continues to support the investigation and expressed condolences to the families affected by the crash.

UPS said in a statement that it is fully cooperating with the investigation and remains focused on the recovery effort.

Images of moments before the November crash showed that during takeoff, the freighter's left engine structure detached and fell on the ground. On Nov. 4, 2025, the Hawaii-bound plane later crashed in an industrial area beyond the runway. The crash and ensuing fire killed 15 people, including the plane's pilots and a victim who succumbed to injuries weeks after the disaster.

Aviation-safety experts have said that the MD-11, a three-engine jet that Boeing inherited through its purchase of rival McDonnell Douglas, can usually fly with two working engines. The NTSB update said it would continue reviewing engineering data to better understand why the airplane didn't gain much altitude after the engine's separation.

Write to Drew FitzGerald at andrew.fitzgerald@wsj.com

(END) Dow Jones Newswires

January 14, 2026 19:58 ET (00:58 GMT)

Copyright (c) 2026 Dow Jones & Company, Inc.