General Discussion

...used to change the engine couldn't hold hydraulic pressure well enough to keep the engine from moving in a sling. The rocking of the engine caused cracks in at least one set of pylons. During takeoff, the weakened pylons broke, but the others didn't, and the engine couldn't break off cleanly. When it did finally detach, it took a big chunk out of the leading edge of the wing. There were some other second- and third-order effects as well, including the fact that the hydraulic system for the slats bled dry from the damage, and some of the warning systems (like stick shakers) were powered by the engine that fell off. (I also think that particular DC10 had no stick shaker on the co-pilot's side--the aircraft manufacturers were nickel-and-diming customers when it came to equipment ).