Investigators have pinpointed the exact fault that caused the crash of a UPS cargo flight in Louisville in November that killed 15 people.
A rare update on the investigation released by the National Transportation Safety Board on Wednesday said the 3-inch-wide metal casing surrounding the bearing, located in the center of the bracket that secures the left engine to the MD-11F wing, showed signs of existing metal fatigue and cracks. Investigators discovered larger gatherings were a problem early in the investigation.
On Nov. 4, three pilots and 12 people on the ground were killed on UPS Flight 2976, which plowed through a half-mile-long debris field over an oil recovery facility and a UPS warehouse, sparking fire and black smoke visible for miles.
As part of the update, investigators released previously unseen images of the alleged bearing race that split in half, causing the left engine to rise and go over the wing of the three-engine jet in a dramatic fireball.
The NTSB highlighted in its latest update that the bearing seats were the subject of a 2011 letter from Boeing to airlines, known as a service letter, warning them of four engine bearing race failures on three different MD-11s. But the National Transportation Safety Board noted the warning to operators that “Boeing has determined that this will not result in safe flight conditions” and requested visual inspections of the part at normal five-year intervals.
Boeing, which took over support for the McDonnell Douglas-built MD-11F after acquiring McDonnell Douglas in 1997, said it “will continue to support the investigation.”
“Our deepest condolences go out to the families who lost their loved ones, and our thoughts go out to all those affected,” a Boeing spokesman said.
In November, the NTSB released a preliminary report on the incident, which revealed that a critical bracket connecting the UPS flight’s left engine failed shortly after the plane left the ground. Data showed the plane failed to climb more than 30 feet above the upper right corner of Runway 17 at Louisville Muhammad Ali International Airport.
Initial reports also highlighted fatigue cracks found in the hardware connecting the engines to the wings and symptoms of excessive stress, but more is still occurring as the agency conducts a full investigation.
Investigators also reviewed flight data recorder information that will be included in a performance study to understand why the plane did not gain altitude.
The NTSB is expected to issue a final report detailing the possible causes of the crash within 18 to 24 months after the incident. The agency did not pursue blame but made recommendations to further improve safety.
correct: An earlier version of this story incorrectly reported the death toll from a UPS cargo flight crash in November. It was 15 o’clock.
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