Boeing told UPS that engine flaw wasn’t flight safety risk before 15 died, officials claim
.jpg?width=1200&auto=webp&crop=3%3A2&ssl=1 "Boeing told UPS that engine flaw wasn’t flight safety risk before 15 died, officials claim")
New documents released by crash investigators reveal that UPS never mandated the detailed inspections necessary to detect a critical flaw that led to an engine detaching from one of its planes before a fatal crash. This oversight occurred despite Boeing having recommended such inspections years earlier.
However, in its submission to the National Transportation Safety Board (NTSB), UPS contended that it did not require these enhanced bearing inspections within the pylons—the structures connecting engines to wings on its MD-11 freighters—because Boeing had incorrectly stated that a failure of these bearings would not compromise flight safety.
The tragic incident unfolded last fall as the plane accelerated down the runway at Louisville’s Muhammad Ali International Airport, resulting in the deaths of all three pilots and 12 individuals on the ground. An additional 23 people sustained injuries.
While investigative hearings in May highlighted the failures that prevented mechanics from closely examining the key components securing the engines, the documents released Wednesday provide further intricate details. The NTSB’s final report on the fiery crash, which occurred in November as the UPS plane attempted takeoff in Louisville, Kentucky, is not expected until late this year or early next. Nevertheless, UPS has stated that it is clear “once the pylon separated from the aircraft, the crash was inevitable.”
Officials from both Boeing and the Federal Aviation Administration (FAA) conceded during the hearings that they had misunderstood the risks associated with the potential failure of a steel bearing and metal sheath within the engine mount before the crash. They had not realized such a failure could lead to the breaking of lugs that secure engines to an MD-11’s wings. These bearings are deeply embedded near the pylons, making problems difficult to detect without removing each engine for thorough inspection.
Aviation safety expert Jeff Guzzetti, who previously investigated crashes for both the NTSB and FAA, asserted that the actions of Boeing, UPS, the FAA, and the maintenance company STE San Antonio Aerospace all contributed to the disaster. “There’s just lots of subtleties and semantics that these four entities are using. But in the end, this got missed and to some degree, all four have some role to play in that,” Guzzetti said. “Safety is a shared responsibility, and I think the NTSB’s task now is to apportion that responsibility.”
Chris Hentz, Vice President of STE San Antonio Aerospace, noted that UPS only instructed its mechanics to check for corrosion, not for signs of bearing failure. Yet, both Hentz and UPS pointed out that even as Boeing acknowledged “changes to the inspection requirement of the spherical bearing were warranted,” the planemaker simultaneously stated in the same letter that existing inspection requirements were sufficient.
Hentz’s letter elaborated that Boeing “stated that while the MD-11 inspection intervals and requirements for an inspection of the aft bulkhead were sufficient, changes to the inspection requirements of the spherical bearing were warranted to ensure that the migration of the outer race would be reliably detected and identified during inspection.”
UPS further stated that, despite Boeing developing an enhanced inspection procedure and adding it to the MD-11 maintenance manual, the planemaker never incorporated it into its federally approved maintenance schedule. “Relying on Boeing’s representations that the issue was not safety-of-flight and that existing MPD inspections were sufficient, UPS determined that no additional changes to its maintenance program were necessary beyond what was already being performed,” the package delivery giant explained.
At one point, Boeing even successfully petitioned the FAA to extend the required inspection schedule from every 19,900 cycles of takeoffs and landings to every 29,260 cycles. This change was intended to allow airlines to complete more major maintenance tasks concurrently, thereby reducing downtime.
The planemaker sought this extension even after receiving reports of seven bearing flaws well before planes reached their original inspection limits. In the years following the relaxed schedule, three more instances were discovered before the crash.
The UPS plane that crashed after losing its engine had completed 21,043 cycles, meaning it should have undergone thorough inspection under the original schedule. While there was another crash decades earlier involving a similar plane model that lost an engine, that incident was attributed to improper maintenance, not to the same flaw.
FedEx and other MD-11 operators reported at least 10 additional instances of failures involving these bearings or their securing parts in the years leading up to the UPS crash. However, it remains unclear what, if any, different maintenance practices these other operators might have employed.
FedEx resumed flying its MD-11s in May after the FAA approved Boeing’s plan to ensure their safety. Following the November crash, engine mounts were closely inspected, and moving forward, the spherical bearings will be replaced regularly after every 4,000 cycles of takeoffs and landings. In contrast, UPS opted to retire its entire MD-11 fleet early after the incident.
