Airbus this year has certified another MTOW bump for the A350-900 up to 283t. The value of these MTOW increases are very underated in my opinion. This recent increase effectively improves the fuel burn per kg of payload by around 1% which is similar to a decent engine PIP program.

In a long haul flight a MTOW increase like this would allow a 3-4% increase in payload weight while fuel load increases by only 1-2% to make the same trip. This is where the gain is made and it will help gain additional sales.

Airbus seems to do these increases very often. The A321NEO went from 93.5t to 97t and now to 101t. The A330NEO went from 242t to 251t. The A350-900 went from 268t to 275t to 280t and now to 283t. The A350-1000 has gone from 308t to 316t and now 319t.

Boeing has never done this. There have only increased weights during a major refresh after 15-20 years.

The A350-900 already has a very high ACN. With only 4 wheels per main wheel gear I'm not sure how much higher the weight can go. I believe this is the highest weight of any aircraft with this gear configuration. This may end up being a limiting factor if they envision any higher weights. It may be prudent for them to focus on bumping up the thrust rating and weight of the -1000.

3rdGen wrote:

The A350-900 already has a very high ACN. With only 4 wheels per main wheel gear I'm not sure how much higher the weight can go. I believe this is the highest weight of any aircraft with this gear configuration. This may end up being a limiting factor if they envision any higher weights. It may be prudent for them to focus on bumping up the thrust rating and weight of the -1000.

No, the A359 is lower than both the 787-9 & 787-10. The tyres on the main gear are spread apart further than the 787 so the pressure (weight/area) is lower.

https://www.icao.int/NACC/Documents/Mee ... 10-P15.pdf

High ACN has long been flagged as a potential limiting factor for truly long-range aircraft. The reality is that the frequency of operations at the highest MTOWs is usually a very small fraction of the operations from potentially limited runways, sufficiently infrequent to not significantly impact runway life The 777-300ER may have six wheel main gear but at 775klbs it's ACN must also be pretty high. How many depart at this weight from the same runways on a regular Basis?

Boeing did it quite succesfully with the 757, I know of aircraft which went from 100 to 103 to 108 to 113t in their lifetime

RJMAZ wrote:

Airbus seems to do these increases very often. The A321NEO went from 93.5t to 97t and now to 101t. The A330NEO went from 242t to 251t. The A350-900 went from 268t to 275t to 280t and now to 283t. The A350-1000 has gone from 308t to 316t and now 319t.

There’s also a 217t version of the A359, specifically for Japan Airlines.
https://www.jal.co.jp/jp/en/aircraft/conf/359.html

RJMAZ wrote:

Boeing has never done this. There have only increased weights during a major refresh after 15-20 years.

Of course they did. They offer several different MTOW versions of the 77W as example.

ben7x wrote:

RJMAZ wrote:

Airbus seems to do these increases very often. The A321NEO went from 93.5t to 97t and now to 101t. The A330NEO went from 242t to 251t. The A350-900 went from 268t to 275t to 280t and now to 283t. The A350-1000 has gone from 308t to 316t and now 319t.

There’s also a 217t version of the A359, specifically for Japan Airlines.
https://www.jal.co.jp/jp/en/aircraft/conf/359.html

Isn't it just a paper derate?

RJMAZ wrote:

Airbus this year has certified another MTOW bump for the A350-900 up to 283t. The value of these MTOW increases are very underated in my opinion. This recent increase effectively improves the fuel burn per kg of payload by around 1% which is similar to a decent engine PIP program.

In a long haul flight a MTOW increase like this would allow a 3-4% increase in payload weight while fuel load increases by only 1-2% to make the same trip. This is where the gain is made and it will help gain additional sales.

Airbus seems to do these increases very often. The A321NEO went from 93.5t to 97t and now to 101t. The A330NEO went from 242t to 251t. The A350-900 went from 268t to 275t to 280t and now to 283t. The A350-1000 has gone from 308t to 316t and now 319t.

Boeing has never done this. There have only increased weights during a major refresh after 15-20 years.

That has been Airbus' philosophy since its inception: do gradual improvements over the life of the aircraft to extract more and more out of it. It has worked quite well so far.

Its great to have MTOW increases, but it doesn't do much for efficiency. For that you need OEW decreases and PIP's from the engines. So at the outer edge of the envelope for airlines having the extra 3T will be great, but how many will use this? Great for us to discuss it, but for an aircraft like the A359 that is already very good at the extreme ranges it will not do much for those 6-12 hour flights that are the bread and butter for most airlines that have ordered it.

enzo011 wrote:

Its great to have MTOW increases, but it doesn't do much for efficiency. For that you need OEW decreases and PIP's from the engines. So at the outer edge of the envelope for airlines having the extra 3T will be great, but how many will use this? Great for us to discuss it, but for an aircraft like the A359 that is already very good at the extreme ranges it will not do much for those 6-12 hour flights that are the bread and butter for most airlines that have ordered it.

What about cargo? That would be good for a MTOW bump

PHLspecial wrote:

enzo011 wrote:

Its great to have MTOW increases, but it doesn't do much for efficiency. For that you need OEW decreases and PIP's from the engines. So at the outer edge of the envelope for airlines having the extra 3T will be great, but how many will use this? Great for us to discuss it, but for an aircraft like the A359 that is already very good at the extreme ranges it will not do much for those 6-12 hour flights that are the bread and butter for most airlines that have ordered it.

What about cargo? That would be good for a MTOW bump

It would, if A350s today go out at (their current, multiple) MTOW. Like extra seats, it only has value when you use it - unlike OEW decreases and PIPs that have value with every flight.

RJMAZ wrote:

Boeing has never done this. There have only increased weights during a major refresh after 15-20 years.

In fact Boeing done it with the 77W. There was one big step (351t) to allow the ME3 to flight to California without payload penalties.

Ronaldo747 wrote:

In fact Boeing done it with the 77W. There was one big step (351t) to allow the ME3 to flight to California without payload penalties.

Correct and they also deleted the tailskid (400kg weight saving) and tweaked the fbw (to reduce chance of tail strike) on later builds of the 77W. There were a few other mods too, but I don't remember them.

The 350 is already an extremely capable airplane at 280t. This will be helpful warding off weight restrictions on wintertime westbound flights, especially if alternates are inconvenient. And of course as an increased freight allowance. I don't think it adds many markets though.

It also further separates its mission profiles from the 787-9.

RJMAZ wrote:

Airbus this year has certified another MTOW bump for the A350-900 up to 283t. The value of these MTOW increases are very underated in my opinion. This recent increase effectively improves the fuel burn per kg of payload by around 1% which is similar to a decent engine PIP program.

In a long haul flight a MTOW increase like this would allow a 3-4% increase in payload weight while fuel load increases by only 1-2% to make the same trip. This is where the gain is made and it will help gain additional sales.

Airbus seems to do these increases very often. The A321NEO went from 93.5t to 97t and now to 101t. The A330NEO went from 242t to 251t. The A350-900 went from 268t to 275t to 280t and now to 283t. The A350-1000 has gone from 308t to 316t and now 319t.

Boeing has never done this. There have only increased weights during a major refresh after 15-20 years.

It's always a good news to see in aircraft gain in capabilities over time.

Regarding Boeing, they've done it on the 787 very early in the program (before the 787-8 certification) when they realized they wouldn't manage to achieve the targeted empty weight. As a result, they already ate a significant part of the margins they had for possible incremental MTOW increases (at that stage, the 787-8 was well past its conceptual and preliminary design phases). Here is a reminder of these MTOW increases:

In December 2009, Boeing published a revised version of the airport planning documents for the 787, showing increases in the maximum take-off weight for all three variants, some of which can be attributed to the increased curb weight. The maximum take-off weight of the 787-3 is now 170,250 kg (plus 5,000 kg), that of the 787-8 227,900 kg (plus 8,400 kg) and that of the 787-9 247,400 kg (plus 2,270 kg).

The 787-9 got a second early MTOW increase:

On May 11, 2011, Boeing announced a further increase in the weight of the 787-9, to 251,000 kg. This increased the maximum take-off weight by approx. 5,800 kg compared to the original plan.

And the MTOW of the 787-9 is now at 254 tonnes.

https://second.wiki/wiki/boeing_787boeing_787-8

Regarding the increase of the A321 MTOW to 101 tonnes, it is more than an incremental increase. It took a redesign of the structure to allow this MTOW increase. This could be justified given the potential market for this new variant.

LAOCA wrote:

The 350 is already an extremely capable airplane at 280t. This will be helpful warding off weight restrictions on wintertime westbound flights, especially if alternates are inconvenient. And of course as an increased freight allowance. I don't think it adds many markets though.

It also further separates its mission profiles from the 787-9.

I could see this MTOW increase to 283t being helpful to DL on the JNB - ATL route.

9252fly wrote:

LAOCA wrote:

The 350 is already an extremely capable airplane at 280t. This will be helpful warding off weight restrictions on wintertime westbound flights, especially if alternates are inconvenient. And of course as an increased freight allowance. I don't think it adds many markets though.

It also further separates its mission profiles from the 787-9.

I could see this MTOW increase to 283t being helpful to DL on the JNB - ATL route.

Unless the MTOW comes with aero/performance tweaks (which is probably doesn’t; Airbus would be making noise about that) that improves take off performance or lowers fuel burn it will make no difference to amount of weight DL can take off with and how far they can fly from JNB. It just means the delta between takeoff weight and MTOW is larger than the 280t planes. The A350 is not taking off with 280t from JNB.

9252fly wrote:

LAOCA wrote:

The 350 is already an extremely capable airplane at 280t. This will be helpful warding off weight restrictions on wintertime westbound flights, especially if alternates are inconvenient. And of course as an increased freight allowance. I don't think it adds many markets though.

It also further separates its mission profiles from the 787-9.

I could see this MTOW increase to 283t being helpful to DL on the JNB - ATL route.

Increasing the MTOW doesn't help this route because the aircraft can't takeoff at MTOW as it is. A thrust bump or maybe a tire that can handle higher speed would help but not just a higher MTOW.

JohanTally wrote:

9252fly wrote:

LAOCA wrote:

The 350 is already an extremely capable airplane at 280t. This will be helpful warding off weight restrictions on wintertime westbound flights, especially if alternates are inconvenient. And of course as an increased freight allowance. I don't think it adds many markets though.

It also further separates its mission profiles from the 787-9.

I could see this MTOW increase to 283t being helpful to DL on the JNB - ATL route.

Increasing the MTOW doesn't help this route because the aircraft can't takeoff at MTOW as it is. A thrust bump or maybe a tire that can handle higher speed would help but not just a higher MTOW.

Interesting, what are the chances of either a thrust bump, or a less likely higher speed rated tire?

9252fly wrote:

JohanTally wrote:

9252fly wrote:

I could see this MTOW increase to 283t being helpful to DL on the JNB - ATL route.

Increasing the MTOW doesn't help this route because the aircraft can't takeoff at MTOW as it is. A thrust bump or maybe a tire that can handle higher speed would help but not just a higher MTOW.

Interesting, what are the chances of either a thrust bump, or a less likely higher speed rated tire?

Well I don't know if the control surfaces could handle the thrust or what other areas would need strengthening but they obviously have the 97k available for the A35K.

WayexTDI wrote:

ben7x wrote:

RJMAZ wrote:

Airbus seems to do these increases very often. The A321NEO went from 93.5t to 97t and now to 101t. The A330NEO went from 242t to 251t. The A350-900 went from 268t to 275t to 280t and now to 283t. The A350-1000 has gone from 308t to 316t and now 319t.

There’s also a 217t version of the A359, specifically for Japan Airlines.
https://www.jal.co.jp/jp/en/aircraft/conf/359.html

Isn't it just a paper derate?

With significant operating cost savings.

Presumably the A330NEO will get another 1-2t soon.

9252fly wrote:

I could see this MTOW increase to 283t being helpful to DL on the JNB - ATL route.

Doubtful since MTOW is not the limiting factor in JNB. Nobody is even lifting 280t from JNB on the A350. Unless there are improvements with respect to tire speed limitations or thrust, this doesn't help. Even tire speed may not be that useful since you'd run out of runway before getting the higher speed. Thrust would be the help, although there are other trade-offs with a higher thrust engine.

smartplane wrote:

WayexTDI wrote:

ben7x wrote:

There’s also a 217t version of the A359, specifically for Japan Airlines.
https://www.jal.co.jp/jp/en/aircraft/conf/359.html

Isn't it just a paper derate?

With significant operating cost savings.

Presumably the A330NEO will get another 1-2t soon.

I don't doubt there is a cost saving; but it's easy to artificially limit an aircraft at 217t MTOW when it has been certified at 280+t MTOW, it's just a paper exercise. Increasing the MTOW, on the other hand, must demonstrate the safety margins are still respected.

Isn't 217t a typo though? It is a marketing document.

a380900 wrote:

Isn't 217t a typo though? It is a marketing document.

No, there are "regional" variants of the A350 (and A330) with lower MTOW on paper as it brings costs/taxes down when operating only short/mid haul flights where you don't need that much MTOW anyway

9252fly wrote:

Interesting, what are the chances of either a thrust bump, or a less likely higher speed rated tire?

What makes you assume it's less likely? ...that's (specialized tire) exactly what was done for DL's 77Ls prior to JNB service, they didn't event take the (already available) thrust bump.

MIflyer12 wrote:

PHLspecial wrote:

enzo011 wrote:

Its great to have MTOW increases, but it doesn't do much for efficiency. For that you need OEW decreases and PIP's from the engines. So at the outer edge of the envelope for airlines having the extra 3T will be great, but how many will use this? Great for us to discuss it, but for an aircraft like the A359 that is already very good at the extreme ranges it will not do much for those 6-12 hour flights that are the bread and butter for most airlines that have ordered it.

What about cargo? That would be good for a MTOW bump

It would, if A350s today go out at (their current, multiple) MTOW. Like extra seats, it only has value when you use it - unlike OEW decreases and PIPs that have value with every flight.

And I don't think many 280t A359s need to go out at MTOW. As an airline, you need to consider if the higher price of the 283t variant is worth the number of times you actually make use of it. But, for an airline like TK for example, this version could make non-stop flights from IST to Australia profitable.

LAX772LR wrote:

9252fly wrote:

Interesting, what are the chances of either a thrust bump, or a less likely higher speed rated tire?

What makes you assume it's less likely? ...that's (specialized tire) exactly what was done for DL's 77Ls prior to JNB service, they didn't event take the (already available) thrust bump.

I'm not totally sure, but I think the Trent-XWB for the A359 already is at its maximum design thrust. For just a small increase in thrust for the A350-1000, RR had to make redesigned version, the TXWB-97. Which could probably be fitted on an A359 too, but not without a redesign of parts of the aircraft as well.

enzo011 wrote:

Its great to have MTOW increases, but it doesn't do much for efficiency. For that you need OEW decreases and PIP's from the engines. So at the outer edge of the envelope for airlines having the extra 3T will be great, but how many will use this? Great for us to discuss it, but for an aircraft like the A359 that is already very good at the extreme ranges it will not do much for those 6-12 hour flights that are the bread and butter for most airlines that have ordered it.

If it can carry the load as before with 2-3T extra cargo it will make a difference. T-O weight increase is not all about range.

LAX772LR wrote:

9252fly wrote:

Interesting, what are the chances of either a thrust bump, or a less likely higher speed rated tire?

What makes you assume it's less likely? ...that's (specialized tire) exactly what was done for DL's 77Ls prior to JNB service, they didn't event take the (already available) thrust bump.

The A350 has much lower takeoff and landing speeds compared to a 787 or 777, many of the speeds are lower than the A330.

frigatebird wrote:

LAX772LR wrote:

9252fly wrote:

Interesting, what are the chances of either a thrust bump, or a less likely higher speed rated tire?

What makes you assume it's less likely? ...that's (specialized tire) exactly what was done for DL's 77Ls prior to JNB service, they didn't event take the (already available) thrust bump.

I'm not totally sure, but I think the Trent-XWB for the A359 already is at its maximum design thrust. For just a small increase in thrust for the A350-1000, RR had to make redesigned version, the TXWB-97. Which could probably be fitted on an A359 too, but not without a redesign of parts of the aircraft as well.

Small increase? The Trent XWB went from 84,200 lbf on the -84 (A350-900) to 97,000 lbf on the -97 (A350-1000); that's a 15% increase, hardly a small bump.

WayexTDI wrote:

frigatebird wrote:

LAX772LR wrote:

What makes you assume it's less likely? ...that's (specialized tire) exactly what was done for DL's 77Ls prior to JNB service, they didn't event take the (already available) thrust bump.

I'm not totally sure, but I think the Trent-XWB for the A359 already is at its maximum design thrust. For just a small increase in thrust for the A350-1000, RR had to make redesigned version, the TXWB-97. Which could probably be fitted on an A359 too, but not without a redesign of parts of the aircraft as well.

Small increase? The Trent XWB went from 84,200 lbf on the -84 (A350-900) to 97,000 lbf on the -97 (A350-1000); that's a 15% increase, hardly a small bump.

Got my numbers mixed up, thought it was from 93 to 97.So you are absolutely right

Airbus has increased the brochure range by 400km due to this mtow increase https://www.airbus.com/sites/g/files/jl ... y-2022.pdf .
IIRC Jon Ostrower had reported last year that this mtow increase comes along with a weigh reduction and fuel burn improvement from RR.

xwb565 wrote:

Airbus has increased the brochure range by 400km due to this mtow increase https://www.airbus.com/sites/g/files/jl ... y-2022.pdf .
IIRC Jon Ostrower had reported last year that this mtow increase comes along with a weigh reduction and fuel burn improvement from RR.

I figured there would be an OEW upgrade we hadn't heard about yet, that's good news.

xwb565 wrote:

IIRC Jon Ostrower had reported last year that this mtow increase comes along with a weigh reduction and fuel burn improvement from RR.

This would be more important to the majority of operators I'm sure. But the option to increase to 283 will undoubtedly be useful for some. I wonder if this will also apply to the ULR? I've no idea if Singapore Airlines struggle at all with the range on the ULR, but having the ability to add an extra 3 tonnes of MTOW might be useful at times perhaps? I don't know if they typically go out fully fuelled or not.

WayexTDI wrote:

smartplane wrote:

WayexTDI wrote:

Isn't it just a paper derate?

With significant operating cost savings.

Presumably the A330NEO will get another 1-2t soon.

I don't doubt there is a cost saving; but it's easy to artificially limit an aircraft at 217t MTOW when it has been certified at 280+t MTOW, it's just a paper exercise. Increasing the MTOW, on the other hand, must demonstrate the safety margins are still respected.

While it's not a big deal, the reduced MTOW version might still require some analysis to be performed as it would on average operate different flight profiles than the heavy versions. This would justify to re-run some fatigue analysis with new fatigue load sets. The low MTOW version might be certified for more flight cycles than the heavy versions since it would be expected to operate shorter and hence more frequent flights.

fjhc wrote:

I wonder if this will also apply to the ULR?

Don't know if it'll apply to WV013 (which is the -ULR's specific designation), but don't see any reason why it couldn't.

fjhc wrote:

I've no idea if Singapore Airlines struggle at all with the range on the ULR, but having the ability to add an extra 3 tonnes of MTOW might be useful at times perhaps?

No, SQ didn't struggle with the -ULRs at all.

In fact, it found that it never really fueled them beyond what a standard A359 could easily hold when departing the west coast; which is why they were replaced by standard aircraft on the LAX run as soon as those birds got the 280tonne MTOW... as they can utilize the front cargo hold, whereas it must be sealed on a -ULR.

The 280tonne standard birds were used to launch the SIN-JFK nonstop for the same reason, but did have to restrict Y loads. The route eventually switched to the -ULRs.

___________________________________

I wouldn't be surprised to see SQ eventually convert the -ULRs back to standard configuration, or sell them as used ACJs (since those will all be in -ULR standard), once the Sunrise A35K specs are firmed.

Way more seats at way more range, with cargo, while maintaining commonality. Would also allow them to add routes like DFW, IAH, and MIA which the -ULR cannot reach; or perhaps allow them to start routes like YYZ, ORD, IAD, and GRU, which are already within the -ULR's range, but which may all benefit from the lower per-seat costs of a larger aircraft.

Almost seems like a no-brainer, to me.

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

ElroyJetson wrote:

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

Are all of DL's A350s just paper uprates to 283T, or are there some older versions (including the leased frames) that have mechanical differences that prevent the bump to 283T?

MIflyer12 wrote:

ElroyJetson wrote:

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

Are all of DL's A350s just paper uprates to 283T, or are there some older versions (including the leased frames) that have mechanical differences that prevent the bump to 283T?

Some of their oldest frames lack the updated winglet and are rated significantly lower.

ElroyJetson wrote:

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

I don't think anyone questions whether the 359 has the legs for 13 to 14 hour flights I think people's apprehension was whether would it carry a full pax cabin and cargo hold. Looking at the DL seat maps these planes are not the least bit full either direction but hopefully the belly is doing better.

ElroyJetson wrote:

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

Think it was UA.

JohanTally wrote:

I don't think anyone questions whether the 359 has the legs for 13 to 14 hour flights I think people's apprehension was whether would it carry a full pax cabin and cargo hold. Looking at the DL seat maps these planes are not the least bit full either direction but hopefully the belly is doing better.

Oh yes there was, and it made no sense as other A350s at the time were flying even longer sectors.

zeke wrote:

ElroyJetson wrote:

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

Think it was UA.

Actually, I think it was about DL, when DL kept the 77Ls on LAX-SYD (until their retirement). Something about A359 diversions points, IIRC (and maybe I don't!)

JohanTally wrote:

Some of their oldest frames lack the updated winglet and are rated significantly lower.

Thank you, JohanTally.

So, are there some DL A359s with the lower MTOW ratings that would lack the range for SYD-LAX with a full load?

Their earliest examples are 275t and I would expect DL to avoid using them on the LAX-SYD route unless the scheduled aircraft goes tech.

"The baseline A350-900 now has a maximum take-off weight of 280 tons, incorporating structural improvements and larger winglets. It was not available when Delta received its first A350 in summer 2017. Even in mid-2018 Delta was receiving 275t variants, regulatory filings show."

https://www.forbes.com/sites/willhorton ... .com&csi=0

RJMAZ wrote:

Boeing has never done this.

Huhhh?? ...Boeing has done that all the time!

When they're not just calling it an "-ER," they're doing it outright to an established variant, as is the case with the 77W, 77L, 748, 744, 788, 789, 738, etc etc.

MIflyer12 wrote:

Are all of DL's A350s just paper uprates to 283T, or are there some older versions (including the leased frames) that have mechanical differences that prevent the bump to 283T?

Ships N512DN and newer have the modifications allowing for 280T.
Not sure what interest or capability they have for 283T.

JohanTally wrote:

ElroyJetson wrote:

Remember a few years ago when some here said the A350 didn't have the legs to fly LAX-SYD for DL?

I don't think anyone questions whether the 359 has the legs for 13 to 14 hour flights I think people's apprehension was whether would it carry a full pax cabin and cargo hold.

A concern that was as ridiculous then, as it is now.

There's one aircraft that can do LAX-SYD at max structural payload, and that's the 77L at 347T.
A 280T A359 will peak at approx 5900nm, before having to trade payload for range.

Anything else, will do a tradeoff.... but that in no way means the aircraft can't take a full or proximately-full pax+bags load.

LAX772LR wrote:

MIflyer12 wrote:

Are all of DL's A350s just paper uprates to 283T, or are there some older versions (including the leased frames) that have mechanical differences that prevent the bump to 283T?

Ships N512DN and newer have the modifications allowing for 280T.
Not sure what interest or capability they have for 283T.

A little help with JNB-ATL payloads, perhaps?

It's just one route. Maybe they don't want to pay for five uprates and then have to worry about sending those frames only. If it's an expensive uprate they might not want to do all of their eligible frames. Something for the analysts to pencil out.

MIflyer12 wrote:

A little help with JNB-ATL payloads, perhaps?

Nope. They're barely able to go out of there at 270ish tonnes due to tire rotation limitations at altitude, depending on condition... meaning really, any of their A350s can do it more or less equally.

Slightly off topic but what makes JNB so unique in regards to tire speed? Plenty of airports are higher, MEX, BOG, ADD, to name a few.. Aircraft are payload restricted out of these airports but I never hear of tire speed as a limiting factor..

DCA350 wrote:

Slightly off topic but what makes JNB so unique in regards to tire speed? Plenty of airports are higher, MEX, BOG, ADD, to name a few..

....but who's attempting to do a 16hr nonstop out of those airports? Answer: nobody.

That's the issue.

JNB otherwise has plenty of longhauls (HKG, SIN, MEL, etc) that operate just fine, albeit with restrictions due to altitude. Just none so severe as ATL's, its longest nonstop, though.

DCA350 wrote:

Slightly off topic but what makes JNB so unique in regards to tire speed? Plenty of airports are higher, MEX, BOG, ADD, to name a few.. Aircraft are payload restricted out of these airports but I never hear of tire speed as a limiting factor..

And you'll still see ET taking stops on west-bound flights from ADD to the US (e.g. ADD-DUB-IAD and ADD-ORD-IAD) that run non-stop on the return. These flights are substantially shorter than JNB-ATL and yet take stops even though ET have very capable aircraft (B77L, B789 and A359).

Tire speed is just one of the limiting factors. Even if you increase tire speed limits without additional thrust you'll likely eventually run out of runway (conceptually). There is a balancing act with multiple constraints trading off against each other, air density (altitude and temperature), runway length, climb profiles, thrust, tire speed, etc. Tire speed became an in vogue conversation here since it was a specific variable that could improve the B77L's performance out of JNB given that the aircraft had the thrust and they still had some runway length to play with. It may not be the limiting factor for another aircraft type all else held constant, or for the same aircraft type at a different field or with different flight planning parameters. With the A359, its relatively big wing means all else being held constant it'll have a lower rotation speed than the B77L, so it doesn't really need the same tire speeds.