UPS MD-11 Crash After Engine Mount Inspections Extended to 29,260 Cycles
A UPS MD-11 lost an engine and crashed in Louisville after its 21,043rd flight cycle, killing 15 people, because Boeing extended engine mount inspections from 19,900 to 29,260 cycles in 2015. The FAA approved the schedule change after a one-month review without addressing seven earlier bearing failures.
1. NTSB Hearing Highlights
The NTSB hearing outlined that Boeing’s request to extend MD-11 engine mount inspections was approved by the FAA in 2015 without sufficient scrutiny. Regulators and manufacturer representatives acknowledged underestimating the risk of steel bearing and sheath failures deep within the pylon assembly.
2. Inspection Schedule Extension
Boeing successfully lobbied to lengthen required inspections from 19,900 to 29,260 flight cycles, citing efficiency gains. The FAA granted approval after a one-month review and did not seek additional data on known bearing defects.
3. Engine Mount Flaw History
Prior to the crash, there had been seven reported bearing failures on MD-11 engine mounts, with three more detected after the schedule change. The steel bearing and metal sheath can degrade unnoticed without complete engine removals, raising risk of lug failures.
4. Crash Details and Impact
On its 21,043rd cycle, a UPS MD-11 lost an engine during takeoff in Louisville, killing three crewmembers and 12 ground casualties, and injuring 23. Under the original maintenance interval, the engine would have faced a detailed inspection before the accident.