To: purple haze
If I understand it correctly the aircraft must be within X minutes of an alternate in the event of a single engine failure. As a part of the certification the 777 had to demonstrate this capability and the capability of operating on one engine for an extended period of time. Also, the engines had to demonstrate a certain level of reliability. It was my understanding that the 777 was granted ETOPS right out of the box because of how it was designed. The probability of losing a second engine is quite small unless the first engine failed due to a fuel problem, which can also effect the second engine.
Several years ago the president of Airbus Industries was giving a speech in the US in order to promote ETOPS for the A310. He too reflected on the probability of losing two engines on a two engine aircraft were highly remote or in probability language 1 10-9 or one time in a billion.
Within a very short time a Canadian 767 almost crashed when both engines flamed out due to fuel starvation. The same thing happened to two DC-9s and a DC-10. Shortly after that an L-1011 almost crashed due to oil starvation in all three engines due to a maintenance error. And, how about the 747 that lost all four engines when the plane flew through a cloud of volcanic ash.
I would dammed well imagine that even though the 777 is certified ETOPS the pilots pucker factor will go up by several orders of magnitude when his first engine fails.
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The Cat