LEAP-X striking back?

CFM said over the weekend that they have four announcements on every of the first four days of this years Paris Airshow regarding LEAP-X customers. It is not clear, whether these are all for the A320neo or some of them will also be for the C919, but apparently CFM is strongly coming back from behind and it remains to be seen if the PurePower GTF engine can hold it's No.1 position on the A320neo.

According to a Bloomberg report, SAS will order the LEAP-X for their 30 A320neo. A few days ago I expected them they will go with the GTF - apparently I was wrong and I will speculate about the reasons a little bit later.
But let us look at the possible reasons of this comeback: if you read the blog entry behind the first link of this, article, there are two interesting things to note: CFM just lately changed the design of the LEAP-X engine:
1. The fan diameter got larger, from 75" before to 78" now.
2. The LPT got an additional stage - now it has seven, just as the GEnx-1B for the B787.

Both changes are good for about 1% in SFC - each. Additionally, I guess CFM changed to size of the core and made it smaller, what could yield in another 0.5% in SFC.
On the other hand, the engine gets larger, produces more drag, gets added weight and the added LPT stage produces extra maintenance costs.
Because of the added drag and added weight, the fuel burn benefit will end up in the range of 1.5-2%. Operating costs could end up being somewhere between 1-1.5% better.
If you study this site, CFM now claims a 1% better fuel burn against the GTF. Is this credible: a few weeks ago, before the design changes were made official, Bernstein, AirInsight and others said (with obviously good knowledge about the situation), that LEAP-X would trail the GTF by about 3%.
So if CFM now claims to be better by 1%, then they probably project their best possible SFC without regarding any development risk. This is not engineering practice, but as it seems, CFM can convince quite a number of customers with that strategy.

Now to the story about SAS and why they might have turned to CFM:
First, they are a flying a lot of  B737NG, thus having a number of CFM56 in their fleet and possibly a good relationship to CFM. A few weeks back they dedided to lease 2nd hand B737-700 and with that opting against the CSeries.
Easy question: who is most interested in CSeries failing in the marketplace:
1. Airbus
2. CFM
For that reason, I could see a campaign to fight all possible CSeries deals in a joint effort from Airbus und CFM. The litmus test for this thesis will be the CSeries' fate at Republic: if Republic now orders the A320neo with the LEAP-X and (sooner or later) cancels the CSeries, I would see this thesis is "proven". Also watch for Qatar...
The thriller just starts here!


  1. Interesting.

    I remain unconvinced at CFM's claim that the Leap will have a 1% better fuel burn than P&W GTF.

    As you commented on my previous article,

    I have noted that CFM announces a 15% explicit fuel burn saving target whereas P&W announces a 16% goal.

    On fuel burn, I'm also told that the PW1524G has exceeded its 16% SFC saving target.

    An employee working at Air France e-mailed me a month ago that the A320neo equipped with PW GTF will have a 5% DOC advantage, but the CFM Leap only has 2%.

    And given P&W GTF's upgrade path & growth potential, by simply raising the gear ratio to 5:1 or running the core hotter should ceramic matrix composite (CMC) technologies mature by 2018, the GTF will easily outperform the Leap regarding fuel burn.

  2. Thank you, Daniel! As you are, I am unconvinced about CFM's claim. The email from AF probably came before CFM changed their design, so the difference might be smaller now. Maybe the real difference now is maintenance costs, with 2 more HPC stages and 4 more LPT stages in the LEAP.