J-class and others...
1. ETOPS Routes "are longer" - not really true - with 3 hour ETOPS I have never been "routed" to stay in a 3 hour circle - and that's London to JFK, Nassau, Caracas, Bermuda etc. The reason the routes "take" longer is simple - 767s are slower! 777 times should be nearer 747, and less than A340 (slowbus)...
2. Prob of Engine fail. ETOPS engines SHOULD be less likely to fail than 4 Eng ac - because they have to be maintained to a higher standard. Try putting that into the equations above...
3. <<I do see your point about being able to continue to the destination>> A 3 or 4 Eng will only continue to Dest when substantially already there. Eng fail before, say ToC, will be back to base PDQ for anyone. And since the 4 Eng is twice as likely (or more) to have an Eng Fail than 2 Eng, a spurious argument I feel...
All in all, look at the experience. (Unfortunately) we have plenty of experience of airliner accidents over the past decade or 2. I have yet to recall one due to an independent double engine failure (by indpendent, I mean where both engines fail for their own reasons. If you run out of fuel / into heavy hail / rain, it doesn't matter how many engines you have).
NoD
[ 18 November 2001: Message edited by: NigelOnDraft ]