[GarySpFc]

Actually that would be the 767 followed soon after by the 757, A300 and A310. However, their ETOPS was only for 120 at the time. The 777 was the first to receive 180-minute ETOPS from its first day of operation.

Can you explain what you mean by the 120 and 180 minute ETOPS? I know ETOPS qualifies each of these planes to fly across the ocean, but the other two items are a mystery.

[COEXERJ145]

ETOPS, as others have said, stands for Extended Twin-Engine Operations. Basically the ETOPS rules govern how far a twin engine aircraft is allowed to fly from the nearest adequate airport. 120 minutes means they must always be within 2 hours of the nearest adequate airport, 180 of course is three hours and now they're looking at 207 or 240 minute ETOPS for aircraft like the 777-200LR.

The rules first came about when aircraft engines were not nearly as reliable as they are now. The chances of losing both engines due to mechanical failure is so remote that it is safe to fly the twin engine aircraft extremely long distance.

[burzum]

As others have discussed ETOPS limits the places a plane can fly. In some cases, this makes a less efficient route. For example, it may be faster to fly from New York to Tokyo by flying over the artic ice cap, but the airplane would be further from an airport than it is rated.