Laurence Doering writes:

Modern airliners are required to have very good single engine
capability to operate on oceanic routes. Do a google search
for ETOPS

Actually, they are required to have 'one-engine-out' performance. Three-engine
aircraft must do it on 2 good engines, and 4-engine aircraft must do it on 3
good engines. ETOPS is only applicable to 2-engine airplanes.