I have recently heard a story about an aeronautical engineer who will not fly on the long trans-oceanic routes in anything less than a Boeing 747 or an Airbus A380. This person claims the reason is safety, and that a twin engine airline jet of similar manufacturing date (and therefore safety features) will never be as safe as a four engine aircraft.
Dick, your whole premise is without basis - i.e. that a quad is safer than an ETOPS operated twin. Now, just so you know, I spent 40 years as a propulsion engineer at Boeing, and I know all about the stuff that went into the original ETOPS approvals (called EROPS back then). Spent several years on the Propulsion Safety Board as well.
The bottom line is this: There has
never been an ETOPS twin go down due to dual, unrelated (i.e. not common cause) engine failures. There have been trijets and quads that have crashed due to
single engine failures. The greatest engine related risk to multi-engine aircraft is not non-common cause engine thrust loss - it's that there is an engine failure that endangers the aircraft - uncontained engine failures being the biggest one with engine fire being a close second. The greater the number of engines, the greater the risk that an engine will fail catastrophically (google Sioux City DC-10 for a rather dramatic example of how a single engine failure can take down an aircraft, and it took a talented crew and more than a little good luck to get that Qantas A380 safely on the ground after the Trent engine uncontained failure).
In short, there is no data that demonstrates a twin, operated under ETOPS rules, is less safe than a quad or a tri. There
is data that demonstrates the opposite. As for your aerospace engineer friend, well the less said the better.