Core Insights - The preliminary report on the UPS freighter crash indicates fatigue cracks in the left engine's turbine securing sections, contributing to the accident that resulted in 14 fatalities [1][2][4]. Aircraft and Incident Details - The McDonnell Douglas MD-11F lost its left engine shortly after takeoff from Louisville, Kentucky, failing to climb higher than 30 feet before crashing [2]. - Dramatic images from the report depict the engine and pylon detaching and exploding into a fireball immediately after takeoff [2]. - The specific aircraft involved was originally built for Thai Airways in the early 1990s and converted into a freighter about 20 years ago, powered by three General Electric CF6 engines [8]. Historical Context - The circumstances of the UPS crash are compared to a 1979 American Airlines DC-10 accident, where a left engine detached shortly after takeoff, although the structural failures occurred in different locations [3]. - The NTSB previously determined that the American Airlines crash was due to improper maintenance, while initial findings in the UPS case do not indicate damage from external factors, suggesting aging as a potential cause [4]. Regulatory Actions - Following the UPS accident, the FAA temporarily grounded all MD-11F cargo jets for inspections, affecting approximately 9% of UPS' fleet and 4% of FedEx's fleet [5]. - The FAA has since expanded grounding directives to other aircraft with similar engine-pylon designs [5]. Investigation Insights - Investigators are examining maintenance conducted on the aircraft weeks prior to the crash, with a detailed visual inspection of the left engine mount structure performed in October 2021 [6]. - The part that failed was not scheduled for another intensive inspection for 8,000 takeoffs and landings, indicating a failure occurred well before the expected maintenance interval [7]. - Definitive conclusions from the investigation may take one to two years to finalize [7].