The 747 was designed when we had little to no history on jet engines in commercial service. Hence the designers designed them to the mathmatical probability of 10 to the -9th criteria and came up with 4 engines as having little to no chance of losing all 4 in the same trip. Now we have tons of data on engine reliability and have much improved reliability. Hence the 2 engine long range aircraft emerge.
the A340 family fails the test when it comes to productivity. Here are the test criteria:
TEST
PAYLOAD: How much can you carry?
RANGE: How far can you carry it?
BLOCK SPEED: How fast can you get it there?
OPERATIONAL FLEXIBILITY: What airports can you get it into and out of?
COST: What are the effects on direct and indirect operating costs?
STYLE: is it esthetically pleasing to the customer?
The A340 fails at its ultra long range capability by leaving a ton of PAX or cargo behind. Just ask Singapore about that one. I believe they still get a check from Talouse each month to cover the 80 plus PAX they have to leave behind each flight to get the 118 it can carry the full 15 hours.
At least 747 Classics can carry their design max weight the entire design flight endurance. And get it there a lot faster.
Better economics per passenger seat? they must mean the meal and drinks they don't have to feed the passengers they left behind..........
