Haven't seen this posted yet, but Southwest reports 737 MAX 8 fuel burn is meeting expectations at 14% below the 737-800. This is the first public mention I know of regarding the LEAP-1B performance in service. After initial reports of a 5% shortfall during development, it seems CFM was able to close the gap after all.

Article at CAPA:
https://centreforaviation.com/insights/ ... ons-392181

Original 14% target specified in 2013:
https://www.ainonline.com/aviation-news ... age-upward

5% shortfall rumored in 2015:
https://www.airliners.net/forum/viewtopic.php?t=775161

mzlin wrote:

Haven't seen this posted yet, but Southwest reports 737 MAX 8 fuel burn is meeting expectations at 14% below the 737-800. This is the first public mention I know of regarding the LEAP-1B performance in service. After initial reports of a 5% shortfall during development, it seems CFM was able to close the gap after all.

Article at CAPA:
https://centreforaviation.com/insights/ ... ons-392181

Original 14% target specified in 2013:
https://www.ainonline.com/aviation-news ... age-upward

5% shortfall rumored in 2015:
https://www.airliners.net/forum/viewtopic.php?t=775161

Isn't the 5% short fall on the LEAP 1A only?

fsabo wrote:

mzlin wrote:

Haven't seen this posted yet, but Southwest reports 737 MAX 8 fuel burn is meeting expectations at 14% below the 737-800. This is the first public mention I know of regarding the LEAP-1B performance in service. After initial reports of a 5% shortfall during development, it seems CFM was able to close the gap after all.

Article at CAPA:
https://centreforaviation.com/insights/ ... ons-392181

Original 14% target specified in 2013:
https://www.ainonline.com/aviation-news ... age-upward

5% shortfall rumored in 2015:
https://www.airliners.net/forum/viewtopic.php?t=775161

Isn't the 5% short fall on the LEAP 1A only?

No, the 5% SFC shortfall was on the 1B. The LEAP-1A at the time was said to have a 2% shortfall. I found a source that says this was confirmed information at the time:
http://www.aviationnews-online.com/unca ... -headache/

It is actually incredible! The 738 NG is already a superb efficient airplane. So it goes from 800 GPH to 700 GPH or something along those lines. The savings is 1,000 gallons per day, per aircraft.

mzlin wrote:

Haven't seen this posted yet, but Southwest reports 737 MAX 8 fuel burn is meeting expectations at 14% below the 737-800. This is the first public mention I know of regarding the LEAP-1B performance in service. After initial reports of a 5% shortfall during development, it seems CFM was able to close the gap after all.

Article at CAPA:
https://centreforaviation.com/insights/ ... ons-392181

Original 14% target specified in 2013:
https://www.ainonline.com/aviation-news ... age-upward

5% shortfall rumored in 2015:
https://www.airliners.net/forum/viewtopic.php?t=775161

Afair B announced 13% per seat
http://www.aspireaviation.com/wp-conten ... .52.38.png
and later found another 1% in flight testing.
<your ainonline.com link>
has seating changed from NG to NEO for Southwest and/or American?

^WN has the same exact seating on it's 737-800 and 737 MAX8.

I believe AA went from 160 seats on it's 737-800 to 172 seats on the 737 MAX8.

mzlin wrote:

fsabo wrote:

mzlin wrote:

Haven't seen this posted yet, but Southwest reports 737 MAX 8 fuel burn is meeting expectations at 14% below the 737-800. This is the first public mention I know of regarding the LEAP-1B performance in service. After initial reports of a 5% shortfall during development, it seems CFM was able to close the gap after all.

Article at CAPA:
https://centreforaviation.com/insights/ ... ons-392181

Original 14% target specified in 2013:
https://www.ainonline.com/aviation-news ... age-upward

5% shortfall rumored in 2015:
https://www.airliners.net/forum/viewtopic.php?t=775161

Isn't the 5% short fall on the LEAP 1A only?

No, the 5% SFC shortfall was on the 1B. The LEAP-1A at the time was said to have a 2% shortfall. I found a source that says this was confirmed information at the time:
http://www.aviationnews-online.com/unca ... -headache/

Perhaps that was so at one time. The situation now seems to be reversed. We know the 1A has bleed pinned open. Lightsaber calcs this to be a 6% hit. I can try to dig up lightsaber's post wrt this.

From memory the leap 1b is now missing by a little bit which the 737 makes up for with aero.

fsabo wrote:

Perhaps that was so at one time. The situation now seems to be reversed. We know the 1A has bleed pinned open. Lightsaber calcs this to be a 6% hit. I can try to dig up lightsaber's post wrt this.

A new LPC was introduced in mid-2017, new deliveries are not flying with open bleed anymore.

fsabo wrote:

Perhaps that was so at one time. The situation now seems to be reversed. We know the 1A has bleed pinned open. Lightsaber calcs this to be a 6% hit. I can try to dig up lightsaber's post wrt this.

From memory the leap 1b is now missing by a little bit which the 737 makes up for with aero.

I do remember quite a lot of discussion about 5% -plus hit to LEAP fuel burn about two years ago. I think it is a lesson about rumors that occur before a final product is in service. It is not a problem now and it probably was never a big problem to begin with...In fact, both CFM and Pratt should have spent less time nit-picking efficiency tweaks and more time introducing a reliable new engine type (ditto RR Trent-1000 and GEnx).

Remember that 5 or 6 % LEAP efficiency loss panic...next time rumors fly !!

Good to hear she is meeting spec.Easyjet ceo was saying a320neo with leap A is at 14.8% better than a320ceo. The pratt is of course a different story once the reliability is sorted- 16%-17%

Can we expect 737 of Course 100% Leap and 320 close 100% pratt ? IF pratt starts to get an advantage 3-5% it must start to show in orders.

olle wrote:

Can we expect 737 of Course 100% Leap and 320 close 100% pratt ? IF pratt starts to get an advantage 3-5% it must start to show in orders.

Engine deals are not just about fuel efficiency, it also includes maintenance, financial package, spare parts etc. There could be plenty reasons to select the CFM powerplant over P&W, even when the latter is 2-3% more efficient.

makes transatlantic much more possible in a 737max. less worrying about headwinds when you know you've got plenty of fuel left in the tanks and breakeven slider is a few seats lower.

fsabo wrote:

From memory the leap 1b is now missing by a little bit which the 737 makes up for with aero.

Nice!

I like the irony here . . . : the new super-high-tech Leap missing efficiency, only to be made up by superb aero of that "50 year old design".

PW100 wrote:

fsabo wrote:

From memory the leap 1b is now missing by a little bit which the 737 makes up for with aero.

Nice!

I like the irony here . . . : the new super-high-tech Leap missing efficiency, only to be made up by superb aero of that "50 year old design".

Please, the 737 has had a myriad of aerodynamic refinements since its inception so it's a bit dishonest to refer to it as an ironclad 50 year old design. Even the A320 of today isn't the exact same design as its 1980's counterparts. Ongoing refinements have been made for both and while aero isn't as significant as the new engines, it still helps the drive for more efficiency by a fair margin. Nice to see when a new model meets its target early on and actually matches the promises the OEM made for it at the outset.

KarelXWB wrote:

fsabo wrote:

Perhaps that was so at one time. The situation now seems to be reversed. We know the 1A has bleed pinned open. Lightsaber calcs this to be a 6% hit. I can try to dig up lightsaber's post wrt this.

A new LPC was introduced in mid-2017, new deliveries are not flying with open bleed anymore.

Do you have a link? I missed the fix is released, but hey, I have kids...

I agree there is more than fuel burn. Pratt cost airlines a fortune with reliability and late engines. Now CFM is slightly late.

If the CFM burns 2% more than the ow1100G, than the 1A is at promise.

PW100 wrote:

I like the irony here . . . : the new super-high-tech Leap missing efficiency, only to be made up by superb aero of that "50 year old design".

That "miss" we're talking about is 13% instead of 14% increased efficiency. Seems to be the super-high-tech Leap is doing pretty good.

AvObserver wrote:

Please, the 737 has had a myriad of aerodynamic refinements since its inception so it's a bit dishonest to refer to it as an ironclad 50 year old design.

More than a bit when you consider the NG wing is so different than the Classic wing. In fact the NG wing is newer than the A320 wing.

Revelation wrote:

AvObserver wrote:

Please, the 737 has had a myriad of aerodynamic refinements since its inception so it's a bit dishonest to refer to it as an ironclad 50 year old design.

More than a bit when you consider the NG wing is so different than the Classic wing. In fact the NG wing is newer than the A320 wing.

That wasn't lost on me but I should have mentioned it since it's the biggest change from the original 737. It was crucial to launching the NG; otherwise the 737 could not have effectively competed with the A320 family going forward. Thanks for chiming in.

KarelXWB wrote:

olle wrote:

Can we expect 737 of Course 100% Leap and 320 close 100% pratt ? IF pratt starts to get an advantage 3-5% it must start to show in orders.

Engine deals are not just about fuel efficiency, it also includes maintenance, financial package, spare parts etc. There could be plenty reasons to select the CFM powerplant over P&W, even when the latter is 2-3% more efficient.

GE claims a LEAP will need 3 shop visits over 25 years vs 5 for Pratt GTF. This is a GE claim, of course. Does anyone have any Pratt rebuttal info?

Glad to see the MAX8 is working out for fuel burn! This one will keep the 737 line going for years.