Boeing (BA) had flagged past failures of a structural component later found cracked on the cargo jet involved in November’s fatal United Parcel Service (UPS) crash, according to a mid-investigation update from U.S. safety officials.
Investigators with the National Transportation Safety Board on Wednesday said Boeing (BA) issued a service notice in early 2011. The notification alerted MD-11 operators to multiple prior failures of a spherical bearing race, a part designed to absorb stress and vibration in the engine mounting system. Boeing (BA) indicated at the time that inspections of the component would be added to routine maintenance checks.
The agency is now examining how those inspection recommendations were reflected in Boeing’s (BA) maintenance manuals and how UPS (UPS) applied them, along with any related communications between Boeing (BA) and the Federal Aviation Administration. Boeing (BA) previously concluded the issue didn’t pose an immediate flight safety risk.
Following the crash, the FAA temporarily grounded MD-11F cargo aircraft while operators conducted inspections and corrective actions, later extending those requirements to planes with similar engine-pylon designs.
A preliminary investigation found fatigue cracking in several engine-mount structures on the McDonnell Douglas MD-11F, which lost its left engine shortly after takeoff from Louisville. The aircraft failed to gain altitude and crashed moments later, killing the crew and people on the ground.
The MD-11, no longer produced, is now flown exclusively in cargo service.