ETOPS is a combination of aircraft and engine type certification, additional equipment (ie: fire suppression), training and maintenance organization certification, and certain maintenance procedures and cross-checks.

For instance, if two engines need to be serviced on an ETOPS plane, two seperate crews must be used. The same crew is not allowed to change out both engines, for fear that they'll duplicate a critical mistake (ie: just like the bozos that installed the wrong parts on that Transat A330).

The Minimum Equipment List is also much more restrictive for ETOPS operation. Many 'deferrable' items under a non-ETOPS regime simply are not at all deferrable under ETOPS.