I have wondered this because the Trent 1000 engines are very similar to the Trent XWB engines on the 787. And if the A350 has better efficiency then why do so many airlines purchase the 787?

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    $\begingroup$ I feel these should be split in different questions. $\endgroup$
    – Federico
    Commented Aug 10, 2015 at 14:48
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    $\begingroup$ Honestly, these kinds of comparisons are hard to do without proprietary information because a lot of the numbers aren't public and efficiency can be measured many different ways. The most common is probably fuel per passenger-mile, but that depends on each individual airline's seating configuration and also ignores any other revenue cargo that might also be on board. And all fuel efficiency numbers will vary with weight, temperature, altitude, exact course, distance flown, etc., which vary from one flight to the next, let alone one aircraft to another. $\endgroup$
    – reirab
    Commented Aug 10, 2015 at 14:53
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    $\begingroup$ Don't forget other market considerations like the fact that 787 was to the market earlier. $\endgroup$
    – Jan Hudec
    Commented Aug 10, 2015 at 17:42

1 Answer 1


The answer as to why companies seem to be favoring the 787 over the A350 is in several parts, none having very much to do with efficiency.

First, a grand total of just 6 A350 XWBs have been built. The A350 is just ramping up production this year, while the 787 has been in production about 5 years now. The 787's teething problems have spurred some interest in its competitor, but as the first composite airliner to start accepting orders, the Dreamliner has a distinct first-mover advantage.

Second, Airbus has seen some production problems in its larger airliners, which tends to make airlines nervous. The A380 saw cancellations totaling over $10 billion in lost revenue primarily due to its inability to make them fast enough, causing Airbus to indefinitely delay production of freight variants that major shipping companies were waiting for. Smaller, older production lines have been doing better but the A380 line is still taking up a lot of Airbus's resources that could be spent making 350s.

Third is simple cost. A 787-8's base price is about \$225 million. An A350 starts at about \$270 million. \$45 million a plane is nothing to sneeze at; it means you can have 6 Dreamliners for the cost of 5 A350s, and the major airlines are buying 40-50 of these planes each so the savings is considerable.

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    $\begingroup$ You should also mention the seat number that are not the same (although it is really close: 242 to 335 for the 787, 280 to 366 for the A350) $\endgroup$
    – Manu H
    Commented Aug 11, 2015 at 13:54
  • $\begingroup$ @ManuH that is true, however the seating numbers are so close with so much overlap that the actual price of each aircraft per passenger seat (and thus the required number of flights to break even) will be dependent on the exact specs of the airline's order. $\endgroup$
    – KeithS
    Commented Aug 11, 2015 at 16:19

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