Boeing B777 is the largest twinjet in the world. This design provides unparalled economy for short distance & high passenger amount routes, such as intra-Asia routes. This also explains why Boeing B777 is so popular in Asia.

But the twin engine design of B777 makes its operation very constrictive due to ETOPS constraints. This making B777 unsuitable for long distance routes with no diversion airports, such as southern hemisphere inter-contrinential routes, trans-Indian Ocean routes & transpolar routes.

Because of this, there is not any orders of B777 from southern hemisphere nor any B777 opreated by southern hemisphere airlines, except Garuda Indonesia & Varig, which is a very stubborn Boeing customer. They choose Airbus A340 or Boeing B747 of quad engine design instead, so the aircrafts can fly safely over large oceans or Antarctic without any diversion airports.

The newly launched Boeing B777-200LR (16000km range, 305 passengers) & B777-300ER (13000km range, 368 passengers) are the heaviest twinjet in the world (368t MTOW), thus they have to be powered by GE90 of 115,000lb thrust. Engines of such high thrust are much less reliable than 60,000lb-thrust class engines, and since B777s are sucject to ETOPS constraints, so the new ultra long range B777 are very unreliable.

This also makes airlines need to design routes of much longer distance for the same starting / ending points than the routes served by quadjets, so to ensure availability of diversion airports along the route. For example, it takes only 12 hours for an Airbus A340 to fly from Sydney to Buenos Aires & fly over Antarctica. But if the route is served by B777, then the aircraft must first go to places like Guam / Taiwan / Japan, then to Hawaii, then US West Coast and finally Buenos Aires, thus making trip time of over 30 hours!!

Thus Boeing's decision to produce ultra long range B777 of 368t MTOW instead of producing quad engines versions of such aircrafts, like Airbus A340-500/600, is the largest joke in aviation industry!!