A 747 with 2 engines out that's already got some altitude and speed is much more "survivable" (still extraordinarily difficult) than a trijet trying to take off

A 747 with 2 engines out that's already got some altitude and speed is much more "survivable" (still extraordinarily difficult) than a trijet trying to take off on 1 engine, which is impossible. Planes can safely land with 0 engines, though this is obviously "not ideal." See: Gimli Glider. (Mostly putting that out there for others.)