BahrainLad
The point is ETOPS rules were put in place for twin operations.
The company went overboard to keep the IFSD figures to a minimum. The first acars to maintrol regarding a westbound trip that was returning to London was met with "had you entered the ETOPS area?"
At the time the "same" engines were being taken off the 400's and put on the 767's as the 400 engines were of a later mod state. All to keep the figures looking good.
My point is that the ETOPS rules were not put into place for the 400 and why include the "same" engines in the IFSD figures bearing in mind the 400 uses the "same" engine in different way. Much longer sectors than the 767 and run at higher thrust settings in the initial flight phase.
The point about IFSD is that a 400 has a greater chance of an IFSD than a twin. I was not talking about an individual engine but any engine.