Is the Max9 performance not what the airlines thought? I’m on AS 760 SAN-MCO and we have to divert to TUS for fuel. I’ve flown this flight a dozen times (on 900’s) without any weight and balance restrictions so not sure why today. The current temp in SAN is 73 degrees F and the runway is 9,401 feet so weather shouldn’t be an issue. My ForeFlight app shows a 1 knot headwind so that shouldn’t be an issue. I would love to know more from those who fly the Max9. TIA

Could have been that they'd need to kick passengers off to take enough fuel for alternates, this way everyone gets to go with a little bit of a delay getting you there.

mhockey31091 wrote:

Could have been that they'd need to kick passengers off to take enough fuel for alternates, this way everyone gets to go with a little bit of a delay getting you there.

Pilot said we would be 5,000# over weight for the 9,400 ft runway length. So Max performance isn’t that much better than the 900ER?

d8s wrote:

mhockey31091 wrote:

Could have been that they'd need to kick passengers off to take enough fuel for alternates, this way everyone gets to go with a little bit of a delay getting you there.

Pilot said we would be 5,000# over weight for the 9,400 ft runway length. So Max performance isn’t that much better than the 900ER?

Y’all are probably carrying gas for two alternates. Summertime in Florida…go figure!
I’d say the only real performance enhancement in the MAX series is a lower fuel burn. It’s a slightly heavier aircraft on the same wing and roughly the same thrust. In fact, compared to the NG, it’s really a pig in the climb once you get above the mid 20s.

Appreciate the insights from everyone! I thought the Max would have slightly better takeoff performance but was wrong.

d8s wrote:

Is the Max9 performance not what the airlines thought? I’m on AS 760 SAN-MCO and we have to divert to TUS for fuel. I’ve flown this flight a dozen times (on 900’s) without any weight and balance restrictions so not sure why today. The current temp in SAN is 73 degrees F and the runway is 9,401 feet so weather shouldn’t be an issue. My ForeFlight app shows a 1 knot headwind so that shouldn’t be an issue. I would love to know more from those who fly the Max9. TIA

There is a lot more to consider than the fact that the runway is 9,401. Yes, nominally, that is true. However, there are obstacles, engine out performance, and as others have alluded to, extra fuel may be needed for various alternates.

The MAX-9 would have no issue taking off at MTOW at sea level and said conditions if there weren't other things to consider.

FYI: The MAX-9 has no issue doing OGG-West Coast, for example.

All that said, there are quite a few variables to take into consideration.

Is this a scenario where the MAX 9 could benefit from the stronger cantelievered gear of the MAX 10, a MTOW increase (compliments of stronger gear), and a Thrust bump of the Leap-1B to 29.5k+ and above? Or is the MTOW where it is fine already, but rather wholly a case of take-off performance.

I know that's allot of supposing, because we haven't actually received any data (publicly) about the take off performance of the MAX 10 w/ the new cantelevered gear that improves the rotation angle. And of course the Thrust Bump to 29.5K+ would consume a bit more fuel.

I listened to a POD Cast today in AviaitonWeek where they briefly discuss GOL's request for a MAX 8ER. So much of the work already exists in terms of what's been done for the MAX BBJs in term of additional fuel (and of course the 9 and 10 have provisions for 1 AUX tank too), but it still may be a MOD too far post MAX 7 and MAX 10 certifications and the reality of EICAS requirements after 12/22/2022. Really depends on how Congress words any proprosed extensions for the MAX 7 and MAX 10 certifications and if it would include language that might keep future MAX 8ER and MAX 9ER developments viable.

For both the MAX 8 and the MAX 9, perhaps a SFP (short field performance) kit could perhaps be offered as a PIP, as well a thrust bump via a PIP, without going the whole HGW/ER version. But then again, would those changes alone be enough to have allowed the flight that the OP asked about on a MAX 9 to carry the full pax load, full fuel load for diversions/alternates, and take off out of SNA on that 9400' runway? Is the MTOW sufficient to do all of that? Would an improved rotation angle and more available thrust been enough to take that flight without the refuel in TUS?

Fun to speculate. In the end.. I suspect we won't see any futher MODS to the 8 or 9... The 7 and 10 are the last 737s.

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon. I flew on a -900er from DTW to DEN in the middle of february on a clear calm day (so fantastic takeoff performance) and taking off from 22L (12000ft long) we didnt rotate til the RJ terminal at Mcnamara, 8000ft down the runway, the damn thing is so long and low, it needs a crazy high Vr to not tailstrike on takeoff.

-900er and max9 are great people movers and print money for the airlines but they need some long runways to depart from

FiscAutTecGarte wrote:

Is this a scenario where the MAX 9 could benefit from the stronger cantelievered gear of the MAX 10, a MTOW increase (compliments of stronger gear), and a Thrust bump of the Leap-1B to 29.5k+ and above? Or is the MTOW where it is fine already, but rather wholly a case of take-off performance.

I know that's allot of supposing, because we haven't actually received any data (publicly) about the take off performance of the MAX 10 w/ the new cantelevered gear that improves the rotation angle. And of course the Thrust Bump to 29.5K+ would consume a bit more fuel.

I listened to a POD Cast today in AviaitonWeek where they briefly discuss GOL's request for a MAX 8ER. So much of the work already exists in terms of what's been done for the MAX BBJs in term of additional fuel (and of course the 9 and 10 have provisions for 1 AUX tank too), but it still may be a MOD too far post MAX 7 and MAX 10 certifications and the reality of EICAS requirements after 12/22/2022. Really depends on how Congress words any proprosed extensions for the MAX 7 and MAX 10 certifications and if it would include language that might keep future MAX 8ER and MAX 9ER developments viable.

For both the MAX 8 and the MAX 9, perhaps a SFP (short field performance) kit could perhaps be offered as a PIP, as well a thrust bump via a PIP, without going the whole HGW/ER version. But then again, would those changes alone be enough to have allowed the flight that the OP asked about on a MAX 9 to carry the full pax load, full fuel load for diversions/alternates, and take off out of SNA on that 9400' runway? Is the MTOW sufficient to do all of that? Would an improved rotation angle and more available thrust been enough to take that flight without the refuel in TUS?

Fun to speculate. In the end.. I suspect we won't see any futher MODS to the 8 or 9... The 7 and 10 are the last 737s.

Boeing went around the block 2016-ish and offered an -8ER with the -9 structure and weights (sort of a BBJ w extra tanks). There were no takers.

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon. I flew on a -900er from DTW to DEN in the middle of february on a clear calm day (so fantastic takeoff performance) and taking off from 22L (12000ft long) we didnt rotate til the RJ terminal at Mcnamara, 8000ft down the runway, the damn thing is so long and low, it needs a crazy high Vr to not tailstrike on takeoff.

-900er and max9 are great people movers and print money for the airlines but they need some long runways to depart from

The MAX-9 is not a 757 rocket, but it’s also far from what you described.

There are many flaws with things you’ve said. You did a highly derated takeoff. Also, it can fly from the OGG runway to west coast with no issue. Also, you aren’t taking runway obstacles into account at places like SAN. Read my above - while, it may be 9,400’ long, that isn’t the issue. It’s terrain, etc.

Please don’t make things up for the sake of it.

FiscAutTecGarte wrote:

Is this a scenario where the MAX 9 could benefit from the stronger cantelievered gear of the MAX 10, a MTOW increase (compliments of stronger gear), and a Thrust bump of the Leap-1B to 29.5k+ and above? Or is the MTOW where it is fine already, but rather wholly a case of take-off performance.

While we must wait till Boeing releases the MAX 10 gear testing data, I think the MAX 10 gear should in theory help the MAX 9 runway performance and allow for an MTOW increase. If the data proves to be fruitful Boeing would be foolish not to offer it as an upgrade to existing and future MAX 9 customers. I've been an advocate for this for a while, especially for Southwest. I believe there is 200 seat airplane in Southwest's future. Whether it will be a MAX 9 or 10 is the question. I think the MAX 9 with the MAX 10 gear could make it a serious contender if it can lift a meaningful payload from MDW, DAL & HOU.

If the runway at SAN was a factor, United would sure be having a hard time with their 7M9s out of OGG.

This had to do with the weather in MCO and nothing else.

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon.

Lol, no.

What kind of range would a 7M9 have without the auxiliary fuel tank?

INFINITI329 wrote:

What kind of range would a 7M9 have without the auxiliary fuel tank?

Bingo -- this is the mostly likely problem. I doubt AK added any belly tanks. Most likely they were fuel volume limited due to high diversion requirement(s). I don't know for sure but I imagine it's around 5 hour sector + 1.5h hold/diverson endurance.

The MAX9 has more usable range than a late-model 738 does. Copa regularly flies their MAX9's greater than 7 hour segments with 160ish pax. I doubt this was a performance limited takeoff unless there was something on the braking system that was MEL'd, hurting RTO performance and greatly limiting weight.

AAPilot48Heavy wrote:

d8s wrote:

FYI: The MAX-9 has no issue doing OGG-West Coast, for example

It's not usually Hawaii-West Coast that is an issue, its the exact opposite. Between the headwind and the extra bias for wind errors etc, it adds a bit more than Westbound with a tailwind vs Eastbound with a headwind. Particularly true in the Winter months (same applies to most NAT ops)

N1120A wrote:

If the runway at SAN was a factor, United would sure be having a hard time with their 7M9s out of OGG.

This had to do with the weather in MCO and nothing else.

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon.

Lol, no.

Lol, yes.

The MAX really is a runway hog, even with 28k engines. It's easy to see the max9 running into tow restrictions from SAN on a slightly warm day like today at isa+10.

I know you won't take my word for it so look at the acaps here, pages 75/76:

https://www.boeing.com/resources/boeing ... X_RevG.pdf

Can't really use flights ex-OGG as an example to further your point as operating weights to LAX/SFO are likely sub 80t.

Chaostheory wrote:

N1120A wrote:

If the runway at SAN was a factor, United would sure be having a hard time with their 7M9s out of OGG.

This had to do with the weather in MCO and nothing else.

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon.

Lol, no.

Lol, yes.

The MAX really is a runway hog, even with 28k engines. It's easy to see the max9 running into tow restrictions from SAN on a slightly warm day like today at isa+10.

I know you won't take my word for it so look at the acaps here, pages 75/76:

https://www.boeing.com/resources/boeing ... X_RevG.pdf

Can't really use flights ex-OGG as an example to further your point as operating weights to LAX/SFO are likely sub 80t.

Except that from 9000' on an ISA+15 day, the -9 can lift ~187000 pounds, just 7000 short of MTOW.

N1120A wrote:

Chaostheory wrote:

N1120A wrote:

If the runway at SAN was a factor, United would sure be having a hard time with their 7M9s out of OGG.

This had to do with the weather in MCO and nothing else.



Lol, no.

Lol, yes.

The MAX really is a runway hog, even with 28k engines. It's easy to see the max9 running into tow restrictions from SAN on a slightly warm day like today at isa+10.

I know you won't take my word for it so look at the acaps here, pages 75/76:

https://www.boeing.com/resources/boeing ... X_RevG.pdf

Can't really use flights ex-OGG as an example to further your point as operating weights to LAX/SFO are likely sub 80t.

Except that from 9000' on an ISA+15 day, the -9 can lift ~187000 pounds, just 7000 short of MTOW.

Or if a glass if half empty... There is a tiny corner on a diagram where MAX9 with -1B27 can actually achieve MTOW.

N1120A wrote:

Except that from 9000' on an ISA+15 day, the -9 can lift ~187000 pounds, just 7000 short of MTOW.

Having worse field performance than most widebodies makes it a hog.

Assuming no obstacles, the 321neo we're awaiting will manage mtow performance upto isa +20 for the same runway length.

Just one point, airliners rarely have to lift max fuel for a max range trip. Look at it performance where it usually operates—legs less than 1500nm.

GalaxyFlyer wrote:

Just one point, airliners rarely have to lift max fuel for a max range trip. Look at it performance where it usually operates—legs less than 1500nm.

This is a crucial point in the discussion. The real world very rarely involves "MTOW from a short runway at 1500ft elevation on a hot day".

Airlines don't make fleet purchasing decisions based on edge cases. They make them based on actual usage in their network.

We are rarely limited on short to medium haul. Plenty of performance to spare,

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon. I flew on a -900er from DTW to DEN in the middle of february on a clear calm day (so fantastic takeoff performance) and taking off from 22L (12000ft long) we didnt rotate til the RJ terminal at Mcnamara, 8000ft down the runway, the damn thing is so long and low, it needs a crazy high Vr to not tailstrike on takeoff.

Yes, but you don't know if they were using a derated takeoff. No reason to run the engines to 90+%N1 and take a maintenance penalty from CFM when you could run them at 75%N1 on a very long runway like DTW where you have plenty of room to take off. A -900/9MAX can definitely get off the ground in much less than 8000ft for a DTW-DEN service if it needed to.

DocLightning wrote:

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon. I flew on a -900er from DTW to DEN in the middle of february on a clear calm day (so fantastic takeoff performance) and taking off from 22L (12000ft long) we didnt rotate til the RJ terminal at Mcnamara, 8000ft down the runway, the damn thing is so long and low, it needs a crazy high Vr to not tailstrike on takeoff.

Yes, but you don't know if they were using a derated takeoff. No reason to run the engines to 90+%N1 and take a maintenance penalty from CFM when you could run them at 75%N1 on a very long runway like DTW where you have plenty of room to take off. A -900/9MAX can definitely get off the ground in much less than 8000ft for a DTW-DEN service if it needed to.

Right on Doc, many on here believe every takeoff is with the engines at TOGA. Just simply not how it works.

Chaostheory wrote:

N1120A wrote:

If the runway at SAN was a factor, United would sure be having a hard time with their 7M9s out of OGG.

This had to do with the weather in MCO and nothing else.

r6russian wrote:

9400 is a very short for a runway hog like a 900 or a max9, expecially for a transcon.

Lol, no.

Lol, yes.

The MAX really is a runway hog, even with 28k engines. It's easy to see the max9 running into tow restrictions from SAN on a slightly warm day like today at isa+10.

I know you won't take my word for it so look at the acaps here, pages 75/76:

https://www.boeing.com/resources/boeing ... X_RevG.pdf

Can't really use flights ex-OGG as an example to further your point as operating weights to LAX/SFO are likely sub 80t.

Thanks for the info! Looking at page 3-61 I see the issue...just not enough runway for the runway hog!

d8s wrote:

Chaostheory wrote:

N1120A wrote:

If the runway at SAN was a factor, United would sure be having a hard time with their 7M9s out of OGG.

This had to do with the weather in MCO and nothing else.



Lol, no.

Lol, yes.

The MAX really is a runway hog, even with 28k engines. It's easy to see the max9 running into tow restrictions from SAN on a slightly warm day like today at isa+10.

I know you won't take my word for it so look at the acaps here, pages 75/76:

https://www.boeing.com/resources/boeing ... X_RevG.pdf

Can't really use flights ex-OGG as an example to further your point as operating weights to LAX/SFO are likely sub 80t.

Thanks for the info! Looking at page 3-61 I see the issue...just not enough runway for the runway hog!

You don't see the issue because we've explained it multiple times. There is a lot more info to take into consideration that you are refusing to look at.

1. OGG-West coast is longer than SAN-MCO and the 737-9MAX gets off a 7,000 runway at OGG, a full 2,000 feet shorter than SAN.
2. AS regularly sends the 737-9MAX on the CHS-SEA leg and Charleston has a 9,000 ft runway, same as SAN -- The flight time is generally about an hour longer than SAN-MCO. AS also flies the less capable 737-900ER on the route.

Just because it isn't a 757-200 doesn't mean it performs terribly.

I’d just add the airport planning manual isn’t a runway analysis and shouldn’t be used as one.

AAPilot48Heavy wrote:

d8s wrote:

Chaostheory wrote:

Lol, yes.

The MAX really is a runway hog, even with 28k engines. It's easy to see the max9 running into tow restrictions from SAN on a slightly warm day like today at isa+10.

I know you won't take my word for it so look at the acaps here, pages 75/76:

https://www.boeing.com/resources/boeing ... X_RevG.pdf

Can't really use flights ex-OGG as an example to further your point as operating weights to LAX/SFO are likely sub 80t.

Thanks for the info! Looking at page 3-61 I see the issue...just not enough runway for the runway hog!

You don't see the issue because we've explained it multiple times. There is a lot more info to take into consideration that you are refusing to look at.

1. OGG-West coast is longer than SAN-MCO and the 737-9MAX gets off a 7,000 runway at OGG, a full 2,000 feet shorter than SAN.
2. AS regularly sends the 737-9MAX on the CHS-SEA leg and Charleston has a 9,000 ft runway, same as SAN -- The flight time is generally about an hour longer than SAN-MCO. AS also flies the less capable 737-900ER on the route.

Just because it isn't a 757-200 doesn't mean it performs terribly.

Some folks are math allergic, unfortunately.

AAPilot48Heavy wrote:

Just because it isn't a 757-200 doesn't mean it performs terribly.

Everything relative to the 75 is poor.

Perhaps I've just been spoiled by my experiences of the last two decades or so, but I tend to think a narrowbody with v speeds and takeoff distances I associate with 777 territory is poor.

GalaxyFlyer wrote:

I’d just add the airport planning manual isn’t a runway analysis and shouldn’t be used as one.

The Boeing acaps tend to match the figures from our fppm and reference rtow tables quite well. Our 777 fleet still has the performance charts on board each aircraft but we refuse to pay Boeing engineering the silly amounts they want for the 787.

What kind of range would a 7M9 have without the auxiliary fuel tank?

Could have been some sort of CDL penalty you weren’t aware of restricting the takeoff weight.


Sent from my iPhone using Tapatalk

DashTrash wrote:

Could have been some sort of CDL penalty you weren’t aware of restricting the takeoff weight.


Sent from my iPhone using Tapatalk

Apologies that I'm going slightly off-topic bringing in a different AC Type's performance.. but great to see you Dash. Were any of your takeoffs in any model of Learjet that you flew ever "derated" to save engine wear?

Apologies if my question brings back bad memories.