> Ground observers reported the aircraft had been delayed for about two hours for work on the left hand engine (engine #1), the engine #1 separated during the takeoff run, the center engine emitted streaks of flames, the aircraft impacted a UPS warehouse and ploughed through other facilities before coming to rest in a large plume of fire and smoke.
https://www.vanityfair.com/news/2015/11/airplane-maintenance...
TDLR 10-20 years ago, the US started allowing maintenance of domestic planes in foreign countries, outside the reach of the FAA’s inspections
See also how FAA allowed Boeing to oversee its own certification for MAX.