ETOPS Critical Systems

[Threethirteen]

Hi all,

This is a potential can of worms, but can anyone help with answers or useful links for the following. It's not so much a series of questions as an area of study;

1.What are the Post-Dispatch Critical Systems on ETOPS 767s?

2.Which Technical failures would preclude ETOPs entry and which would entail immediate Diversion?

3.Which failures are acceptable to allow continuation with 180 (120) min ETOPs?

i.e, When Airbourne, the MEL is of reference interest only and a certain amount of Airmanship takes effect.

Thanks in advance,

313.