Ejaymd11 From United States of America, joined Feb 2001, 193 posts, RR: 0 Posted (13 years 6 months 1 week 5 days 6 hours ago) and read 2677 times:
What exactly caused the MD-11 fuel burn problems. I heard two different reasons one was the design, and the other was the engines chosen by McDc where guzlers. So my question is which is it, also wouldn't the MD-11 3 small engines burn just as much fuel as the 777's 2 large engines, or the A340 4 engines. One more thing, is there a better engine than what the MD-11 has that would have made the current fuel burn problem non existant.
Jsf119 From United States of America, joined Jul 2001, 196 posts, RR: 0
Reply 1, posted (13 years 6 months 1 week 5 days 3 hours ago) and read 2653 times:
Many different things could cause bad fuel burn. It could come from all major modules of the engine from compressor wear to bad fuel nozzels all the way to turbines. The MD-11 has the same engines as a 747,767,A300,A310,A330 and I believe that is all. These engines are getting older so the three big engine companies are working on ways to better the modules. The 777 has bigger engines than the MD11 therefore its fuel economy is better because of newer technology and bigger bypass. The A340 operates with the CFM-56 which are much smaller and in a different thrust class than the MD11. To answer your last question everyday these problems are being worked on in devolpment departments with Pratt, G E and Rolls. The changes are out there just not everyone knows they are.
LAXINTL From United States of America, joined May 2000, 26326 posts, RR: 50
Reply 2, posted (13 years 6 months 1 week 4 days 11 hours ago) and read 2606 times:
One of the main reasons the MD-11 fuel burn problems is that the aircraft is simply heavier than promised and thus misses the performance guarantees at various weights.
Due to the aircraft being heavier than planned several performance improvements were launched in the early 90's which were able to gain back much of the lost performance, however overall the aircraft still performs worse than the origional planned numbers.
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