The National Transportation Safety Board (NTSB) identified the failed part that contributed to a fatal UPS plane crash in Louisville, Ky., last year.

An aircraft that crashed in flames in Kentucky in November had a structural flaw that had been identified by Boeing on similar planes 15 years ago, according to investigators.

The NTSB said cracks in the engine mount components were not detected during routine maintenance, and the aircraft was not due for another detailed inspection for thousands of additional flights.