[supercat]

How is crossing the Atlantic with three engines (a 747 with one out) any less safe than crossing the Atlantic with two engines (on a two-engine A310 or 777)?

What would be the range of the aircraft if it lost another engine on the same side? Three-engine aircraft can operate on any two, but I would expect a 4-engine aircraft to be problematic at best with two same-side engines; even the case of flying with near-left and far-right or vice versa would seem difficult (there's not a whole lot of extra thrust, and some would have to be wasted to keep things balanced).

[FreedomCalls]

What would be the range of the aircraft if it lost another engine on the same side? Three-engine aircraft can operate on any two, but I would expect a 4-engine aircraft to be problematic at best with two same-side engines; even the case of flying with near-left and far-right or vice versa would seem difficult (there's not a whole lot of extra thrust, and some would have to be wasted to keep things balanced).

Read it again. The A310 and 777 are not three-engine aircraft -- they are two-engine aircraft and thousands of them cross the Atlantic every day. Are you worried about asymmetrical thrust on one of those after losing an engine?