Boeing flagged 4 other failures on broken part from fatal Louisville UPS crash
AI-generated summary reviewed by our newsroom.
- NTSB analysis found fractured spherical bearing race with fatigue cracking evidence
- Boeing warned in 2011 about similar bearing failures on three aircraft
- FAA grounded MD-10/MD-11/DC-10 fleet and ordered inspections after crash
A broken part from the UPS airplane that crashed and killed 15 people in Louisville in November was highlighted by Boeing in 2011 for experiencing failures on three different airplanes.
The new information comes from the latest report on the Nov. 4 crash of the parcel plane issued by the National Transportation Safety Board.
NTSB investigators have combed through evidence to try and determine why the Honolulu-bound McDonnell Douglas MD-11 crashed shortly after takeoff near Muhammad Ali International Airport. Investigators have not officially determined the cause of the plane crash.
Wednesday, the NTSB shared new analysis of the plane’s spherical bearing race, which was found fractured.
“The spherical bearing race, which is normally one piece and housed within the lugs of the aft mpunt bulkhead, was found fractured into the forward and aft portions,” the NTSB wrote in the report.
The bearing race is one part that makes up the spherical bearing assembly, installed on the left wing clevis. The plane’s wing clevis support would have been due for a special detailed inspection at 28,000 cycles, but the plane was at 21,043 cycles at the time of the crash, the NTSB previously said.
Further analysis of the bearing race found fracture surfaces on the interior surface, which showed signs of fatigue cracking around the entire edge of the recess groove, according to the NTSB. The fatigue cracking broke through the bearing race to the exterior surface.
The spherical bearing assembly on the UPS plane was highlighted in a 2011 service letter from the plane’s manufacturer, Boeing, citing four other similar assemblies on three different airplanes that experienced mechanical failures, according to the NTSB. Each of the previous four failures was initiated at the recess groove on the interior surface of the bearing race.
“The failure of these spherical bearing assemblies was visually identified by observing the displacement of the fractured bearing race pieces beyond the outer surface of the lugs,” the NTSB said in the report.
The service letter said the spherical bearing failures were not considered serious enough to compromise the safety of a flight, according to the NTSB. Still, the letter said spherical bearing assembly inspections would be included in a general visual inspection and detailed visual inspection, which is normally performed every five years.
The NTSB said it is continuing to investigate the plane’s spherical bearing assembly inspection records, if UPS implemented the recommendations from Boeing’s service letter to its maintenance program and the communications between Boeing and the Federal Aviation Administration before and after the service letter’s publication.
Another part of the plane that showed signs of fatigue cracks and evidence of overstress were the lugs that bolted together the aft mount that attached the left pylon to the plane’s wing, the NTSB previously said. The lugs were not inspected prior to the crash, as UPS’ maintenance program only requires them to undergo a special, detailed inspection at 29,200 cycles.
The 15 victims from the crash include three crew members and 12 people on the ground. The 15th victim, Alain Rodriguez Colina, died Christmas morning, 51 days after the crash.
Todd Inman, an NTSB member, previously said the left engine and pylon of the plane detached during takeoff, causing the plane to plummet and crash into multiple businesses near the airport. A “repeating bell” was heard on the plane’s cockpit recording only seconds before the crash.
Since the crash, the Federal Aviation Administration has grounded all MD-11 and MD-11F aircraft until they undergo inspections and any necessary repairs. The FAA also grounded all MD-10 and DC-10 aircraft because the engine-pylon structure of those planes is similar in design to MD-11 aircraft, and the unsafe condition is “likely to exist or develop.”
