NTSB Identifies Faulty Engine Mount in UPS Flight 2976 Crash

The National Transportation Safety Board (NTSB) has provided critical updates regarding the investigation into the crash of UPS Flight 2976, which occurred on November 4, 2025. The NTSB has pinpointed a faulty engine mount bearing as the cause behind the separation of the left engine from the aircraft, leading to a fire and ultimately a crash shortly after takeoff from Louisville.

On January 14, 2026, NTSB spokespersons confirmed that the failure stemmed from a three-inch (7.62-centimeter) mount bearing, a crucial component of the engine mount. This specific part had been flagged by Boeing approximately 15 years prior, highlighting long-standing concerns regarding the safety of the MD-11’s engine mount design.

Details of the Investigation

The investigation revealed that the aft mount bearing associated with the left engine’s pylon had failed. Analysis of the wreckage showed that two lugs intended to secure the bearing assembly had fractured, and the spherical bearing race was found to be cracked into two sections. These failures indicated signs of fatigue cracking that had likely developed over time.

The aircraft, identified as N259UP, had not been fitted with the updated bearing design recommended by Boeing. In response to earlier failures of similar components, the Federal Aviation Administration (FAA) had issued a service bulletin that included recommendations for inspecting and replacing the bearings. However, compliance with these recommendations was not mandatory, raising questions about the regulatory framework surrounding the MD-11’s maintenance.

Boeing’s awareness of issues with the MD-11’s pylon bearings led to the issuance of a service bulletin after four previous incidents involving bearing failures. Despite this, no mandatory airworthiness directive was enacted, leaving operators with the discretion to implement the recommended changes.

Implications for Airlines and Safety Oversight

The NTSB’s findings have significant implications for the future of the MD-11 fleet. Following the crash, the FAA issued an emergency airworthiness directive that effectively grounded all US-registered MD-11 aircraft while awaiting corrective measures. This directive has resulted in the indefinite grounding of a fleet that includes many aircraft over 30 years old.

Despite the potential for costly redesigns, airlines like FedEx Express remain optimistic about the future of their MD-11 fleet, expressing confidence that the necessary repairs to the mount bearings will be both affordable and expedient. Once the FAA issues specific corrective actions, it is anticipated that these aircraft will return to service promptly.

Investigators are also focusing on the maintenance practices at UPS Airlines. Prior to the crash, the aircraft had undergone a visual inspection of its left pylon in 2021. The NTSB will assess whether the aircraft had completed all required inspections and why maintenance personnel did not identify the fatigue cracking that ultimately contributed to the failure.

As the investigation continues, the NTSB’s findings will likely prompt a reevaluation of safety protocols and maintenance standards for aging aircraft. The focus will be on understanding Boeing’s rationale for not imposing mandatory compliance measures over the past decade and a half, and how this oversight will influence the aviation industry’s approach to safety in the future.