This is not a silly A vs B question. Both are very clearly great machines, but what would make an airline choose one over the other. In which aspect does the Max trump the NEO and visa versa. There is I’m sure carriers that simply want fleet commonality that forces the decision.

Often it's just whoever offers them the best deal. If they want to buy new planes, they negotiate with both Airbus and Boeing and they get two competing offers. Not seldom it happens they use those offers in the negotiation process. "Hey Airbus, Boeing just made me a deal that's better than yours. What are you going to do about it?" Then Airbus gives them a little more discount so they got the better deal. And then it's back to Boeing. "Airbus just made me a better deal, what are you going to do about it?" And that goes on until one gives in.

There are some differences. The A320 takes freight cans while the 737 is bulk loaded. The difference is that in the right conditions an A320 can be loaded much more quickly. That said you need more people and/or equipment to do this. The 737 on the other hand is lower to the ground and doesn’t need as much equipment to load it. There are other differences obviously but this is one of the big ones.

"freight cans" Reminded me of this chestnut.
viewtopic.php?f=5&t=757033&p=10919033&hilit=%22freight+cans%22#p10919033

And these deals can be very complex, performance guarantees and penalties, trade-in deals, future support, equippage or incorporation of options, delivery dates. See Delta’s deal with Boeing on 737-900 options.



GF

The A320NEO offers better fuel burn, especially on long segments. But Airbus cannot build enough to satisfy all demand, and airlines that have large 737 fleets will accept the fuel burn penalty to avoid having to switch. I suspect Boeing is having to offer better deals, and still they are losing market share, from what I have seen. The split was pretty much 50-50 before the NEO, but I think it is now closer to 60-40 in Airbus’s favor. But I also think the GTF’s teething troubles have helped the MAX.

Does the Max have any area of its performance envelope (payload, range, fuel burn) that is better than the NEO?

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

My understanding was the 737-9 Max has better fuel burn per seat than the competitor. Is that not correct? Anyone have the data?

Air Canada supposedly had an internal presentation showing why they chose the 737 Max over the A320 NEO, despite already having a fleet of A32x airplanes. It would be interesting to see that. They aren't dummies so presumably they had a very good reason to flip that part of their fleet.

BoeingGuy wrote:

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

Hook line and sinker, and more takers ?

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

Okay, I just saw the brick wall and Loc antenna even that you apparently refer to.

The 737 hits a brick wall and damages the fuselage. Yet the airplane is so solidly built, the crew doesn't realize it and climbs to FL360 and continues to fly safely. Then the airplane diverts safely when they are informed of it. The airplane spends 4:15 hours in the air despite structural damage and lands safely.

I think you made the point why someone might want a 737. Thank you very much.

Boeing says the NG has better performance than the NEO, and we know they'd never lie, so that's one reason.

BoeingGuy wrote:

Air Canada supposedly had an internal presentation showing why they chose the 737 Max over the A320 NEO, despite already having a fleet of A32x airplanes. It would be interesting to see that. They aren't dummies so presumably they had a very good reason to flip that part of their fleet.

Air Canada / Trans-Canada Air Lines has a very long history of always buying the right aircraft. So when they chose the 737 Max, I was astounded. I watched the PowerPoint presentation available for employees to view and yes, the argument was pretty compelling. In all honesty though, I am sure an equally compelling argument toward the A320neo could also have been presented.

Sadly, as far as I am aware, the 737 Max presentation is not in the public domain.

I think though, the biggest reasons include things like the Max was available two years ahead of the A320neo and with the penalty credits for the huge 787 delays, I'd be surprised if Air Canada paid very much for them. With such a huge backlog, Airbus likely wasn't too open to "discounts". To Boeing's credit, the aircraft does exactly as they promised (even a little better) and the entry into service was a breeze.

zeke wrote:

BoeingGuy wrote:

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

Hook line and sinker, and more takers ?

So basically you just admitted to trolling, pretty childish Captain....

My understanding was that one is more efficient on shorter segments and the other is better on long segments. So route length could determine which would be more fuel efficient for a given airline.

SEPilot wrote:

The A320NEO offers better fuel burn, especially on long segments. But Airbus cannot build enough to satisfy all demand, and airlines that have large 737 fleets will accept the fuel burn penalty to avoid having to switch. I suspect Boeing is having to offer better deals, and still they are losing market share, from what I have seen. The split was pretty much 50-50 before the NEO, but I think it is now closer to 60-40 in Airbus’s favor. But I also think the GTF’s teething troubles have helped the MAX.

Good grief. Yes the A321 has the advantage over the 739 but that just isn't the case with the 738 vs A320. Just watch JetBlue's A320 fleet vs DL and UA with their 738's out of NYC and BOS in the winter.

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

Yeah and the A320 is good when you need to clear a bunch of trees.

HI442ct wrote:

zeke wrote:

BoeingGuy wrote:

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

Hook line and sinker, and more takers ?

So basically you just admitted to trolling, pretty childish Captain....

To be fair, it was pretty obviously a joke. I'm not sure that something that obvious can be counted as trolling.

Yes very efficient at doing that on a industrial scale, that’s what I thought of in that scene in American Made where Cruise goes through those trees at the end of the runway !

TTailedTiger wrote:

SEPilot wrote:

The A320NEO offers better fuel burn, especially on long segments. But Airbus cannot build enough to satisfy all demand, and airlines that have large 737 fleets will accept the fuel burn penalty to avoid having to switch. I suspect Boeing is having to offer better deals, and still they are losing market share, from what I have seen. The split was pretty much 50-50 before the NEO, but I think it is now closer to 60-40 in Airbus’s favor. But I also think the GTF’s teething troubles have helped the MAX.

Good grief. Yes the A321 has the advantage over the 739 but that just isn't the case with the 738 vs A320. Just watch JetBlue's A320 fleet vs DL and UA with their 738's out of NYC and BOS in the winter.

Where does the B have the advantage here? Payload?

IIRC Boeing got the 737 to do US (and other) transcontinental several years before Airbus, put the fancy tips on wings several years earlier, and built a lot of sales momentum on that. And the 737 was a little lighter (not sure that is true anymore). WN and Ryan are two of the most profitable airlines flying. The MAX8 continues to excel, and the other models are OK. The 320 generally excels but not enough to stop 737 sales. And Boeing guessed better on the new engines. I could write a similar paragraph on 320 strengths. I'll let someone else do that.

frmrCapCadet wrote:

And the 737 was a little lighter (not sure that is true anymore).

Its is still lighter - those midget size length landing gear (so maligned because of engine fan size limitation) and lack of lack of MLG doors do save weight. Then there's the lack of overwing exit slide (allowed because low height) as well.
because the B737 is bulk loaded and doesn't accept containers in the cargo hold, I think there's a fair bit of weight savings in the doors and interior equipment.
finally, the simple fact of a 5" or so narrower fuselage leads to savings.

If you think about it, its pretty amazing that A320 overcomes all this to achieve better than parity.
History has shown they are both great aircraft, and I'm sickened by the constant A vs B pettiness of a.net

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

very poor form.

100 demerits.

The market has been clear.
It LOVES the:
737-8
A321neo.

Says it all.

cheers

frmrCapCadet wrote:

IIRC Boeing got the 737 to do US (and other) transcontinental several years before Airbus, put the fancy tips on wings several years earlier, and built a lot of sales momentum on that.

Winglets were added to stay competitive versus A320 with just those endplates fitted.
When Airbus finally added their "sharklets" wingtip thingies they seem to have
achieved near twice the gain that the Aviation Partners solution they tested earlier
had to offer.

BoeingGuy wrote:

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

Okay, I just saw the brick wall and Loc antenna even that you apparently refer to.

The 737 hits a brick wall and damages the fuselage. Yet the airplane is so solidly built, the crew doesn't realize it and climbs to FL360 and continues to fly safely. Then the airplane diverts safely when they are informed of it. The airplane spends 4:15 hours in the air despite structural damage and lands safely.

I think you made the point why someone might want a 737. Thank you very much.

Too early to say structural damage. From what I hear, the composite fairing linking 2 parts of the fuselage was sliced right through. Pilots were able to pressurise the cabin and the systems did not report any problems which is why the pilots continued flying for 4.15 hours.

BawliBooch wrote:

Too early to say structural damage. From what I hear, the composite fairing linking 2 parts of the fuselage was sliced right through. Pilots were able to pressurise the cabin and the systems did not report any problems which is why the pilots continued flying for 4.15 hours.

Guaranteed to have damage, however damage is not the same as catastrophic failure. Since accidents like Aloha Airlines Flight 243 all airliners are designed to be damage tolerant. Even if an antenna was to puncture the fuselage, it should not result in a catastrophic failure, nor should it stop pressurization. The aircraft has an outflow valve located under the right rear door that is about the size of a cabin window. That value position could close in response to a puncture and still retain pressurization. Air is continuously being let out of that valve during flight and new air coming in from the packs.

I had a good chuckle over this ....N14AZ wrote

“While waiting for landing in Bombay the passengers spent their time by signing all together:

„All in all it's just another brick in the wall.“”

N14AZ wrote:

readytotaxi wrote:

While waiting for landing in Bombay the passengers spent their time by signing all together:

„All in all it's just another brick in the wall.“

zeke wrote:

I had a good chuckle over this ....N14AZ wrote

“While waiting for landing in Bombay the passengers spent their time by signing all together:

„All in all it's just another brick in the wall.“”

N14AZ wrote:

readytotaxi wrote:

While waiting for landing in Bombay the passengers spent their time by signing all together:

„All in all it's just another brick in the wall.“

Given the origin of the flight it is highly unlikely the passengers were singing THAT song!

More likely they were singing the "Why this Kolaveri di...?" song.

[Warning - Do not google for this song. Guaranteed to become an earbug!]

E.g:
- fleet commonality (crew, MRO)
- slot availability
- price
- financing (over time)

There is clearly a favourite of the MAX 8 over A320neo but the A321neo over MAX9/10, just based on airlines.

Many airlines ordered split MAX8/A321neo fleets but none ordered the opposite. Clearly a benefit of the MAX 8 on the shorter sectors and the A321neo on the long sectors.

Airline examples are AA, KE, DY, TK, VJ... (and possibly more including in the future). None the reverse clearly shows the generic preference for the large airlines that aren’t 1 type airlines.

T54A wrote:

Does the Max have any area of its performance envelope (payload, range, fuel burn) that is better than the NEO?

The Max still has better range due to a higher fuel volume.

Chemist wrote:

My understanding was that one is more efficient on shorter segments and the other is better on long segments. So route length could determine which would be more fuel efficient for a given airline.

That was the case with the ceo vs NG. The NG would have a 1% or so fuel burn advantage on a trip fuel basis for the first 2 hours (due to lower aircraft weight) at which point the better fuel efficiency of the ceo engines would match and then overcome it.

TTailedTiger wrote:

Good grief. Yes the A321 has the advantage over the 739 but that just isn't the case with the 738 vs A320. Just watch JetBlue's A320 fleet vs DL and UA with their 738's out of NYC and BOS in the winter.

Nothing to do with fuel burn and everything to do with fuel volume.

FlyHappy wrote:

Its is still lighter - those midget size length landing gear (so maligned because of engine fan size limitation) and lack of lack of MLG doors do save weight.

That circa 2t weight advantage in favour of the Boeing is pretty much gone.

Depending on the engine chosen, the neo is 1700-1850kg heavier than the ceo with the Pratt GTF option being the lightest.

The -8 Max has gained 3t over the -800NG. I wonder how the -10Max will fare?

zeke wrote:

BoeingGuy wrote:

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

Hook line and sinker, and more takers ?

Nope, not clever.

Very poor taste.

One might instance the AirAsia 320 that came down stalled in Direct Law from FL350 or so.

Or the Air France 330 same same over the Southern Atlantic.

But that would be trolling.

Just like your post.

This is all so predictable. Both Airbus and Boeing build good airliners and pilots generally have strong feelings about the merits of both manufactures. You cannot however overlook the lessor qualities of the Airbus flight envelope protection system. Sorry if that offends you.

BravoOne wrote:

This is all so predictable. Both Airbus and Boeing build good airliners and pilots generally have strong feelings about the merits of both manufactures. You cannot however overlook the lessor qualities of the Airbus flight envelope protection system. Sorry if that offends you.

Which lessor qualities are these?

No accident involving an Airbus has ever found the envelope protection to have been a major contributory factor.

the 777 and 787 simply have better Envelope Protection system than the Bus. The AF330 had it been either of these Boeing aircraft would probably not happened Please note:..I'm not saying the A330 was the cause of this accident but rather pilot would have had a better chance at recovery had he been in a Boeing. Sorry if that bothers you. Sometimes the facts hurt.

I don't have the time nor inclination to beat this subject to death. If you want to continue I suggest you start a new thread as we have drifted off topic.

There are many factors involved in a decision

• Fuel burn
• Capacity
• Maintenance costs including schedule and unscheduled maintenance cost
• Dispatch Reliability
• Spare part availability and overhaul costs
• Cargo Capacity
• Range
• Payload
• Runway Performance
• Purchase Price including leasing and financing options
• Export Credits including government influence
• Residual Value
• Mitigating factors such as when the airline is also a supplier for maintenance and repair, parts, etc
• Navigation capability and options
• Commonality with existing fleet
• Availabilty
• Enhanced negotiating power which can include restructuring other orders, adjusting payment schedules, purchasing or taking back old airplanes. Etc

Both manufacturers say their plane is the best. The OP asked for this not to be an AvsB discussion, so I won’t respond to posts saying one is better than the other, but I will say that each airline has a unique set of operating requirements which results in different airlines having different choices.

One example of an order being decided based on factors unrelated to the airplane is when Delta ordered the A321neo in exchange for Delta Tech Ops winning the contract to overhaul PW1100Gs in North America. Every order is unique and bigger airlines or government influenced/owned Airlines can have far more complexities associated with an order than just which plane costs less.

BravoOne wrote:

I'm not saying the A330 was the cause of this accident but rather pilot would have had a better chance at recovery had he been in a Boeing. Sorry if that bothers you. Sometimes the facts hurt.

And Asiana 214 would not have happened in (any) Airbus right back to the old A300 designed in the early 1970s.

For the record, the solution of both incidents is better training. High altitude full stall detection and recovery is now a part of training. (It was not trained before AF447). It is very eye opening to see exactly how much altitude is lost during the recovery of such an event!

longhauler wrote:

Air Canada / Trans-Canada Air Lines has a very long history of always buying the right aircraft. So when they chose the 737 Max, I was astounded. I watched the PowerPoint presentation available for employees to view and yes, the argument was pretty compelling. In all honesty though, I am sure an equally compelling argument toward the A320neo could also have been presented.

Sadly, as far as I am aware, the 737 Max presentation is not in the public domain.

I think though, the biggest reasons include things like the Max was available two years ahead of the A320neo and with the penalty credits for the huge 787 delays, I'd be surprised if Air Canada paid very much for them. With such a huge backlog, Airbus likely wasn't too open to "discounts". To Boeing's credit, the aircraft does exactly as they promised (even a little better) and the entry into service was a breeze.

Indeed, most airlines would be hard-pressed to make a wrong choice between the 737 MAX and A320neo; they're both very capable aircraft. The competition has simply become so intense in this segment between the two that any large weakness in the product may be the death knell for it.

I too was surprised when Air Canada chose the 737, given its history and familiarity with the A320 (since the '80s!). Boeing must've made a heck of an offer to offset the cost of retraining pilots.

While Air Canada has a generally good history of choosing the right plane for the job, I wouldn't say always. The A340-500 was a swing and a miss and they seem to be excited to be rid of the E190s. Otherwise, the longevity of their fleets of aircraft seems to indicate they're happy with them.

wave46 wrote:

While Air Canada has a generally good history of choosing the right plane for the job, I wouldn't say always. The A340-500 was a swing and a miss and they seem to be excited to be rid of the E190s. Otherwise, the longevity of their fleets of aircraft seems to indicate they're happy with them.

I do agree that the A340-500 looks like a whiff, but when you consider that the aircraft type selection was made as a part of the A330-300, A340-300, A340-500 and A340-600 fleet, with associated commonalities, it makes more sense. When introduced, it was the only aircraft built that could operate YYZ-HKG non-stop. The A330/A340s were also operated under one pilot type endorsement group, (with currency restrictions). The pilot conversion courses A330/A340 to and from the A320 were all "short courses". It all made sense at the time.

Another consideration might be why the A330/A340 series over the brand new 777-200ER? At the time, Transport Canada would not allow Air Canada to operate such a new airframe/engine combination under ETOPS rules until at least 12 months of "history". The A340s came right out of the box with unrestricted operations. (The early 1990s were a very different time).

When retired, the E175/E190 series will have spent just over 15 years with Air Canada. Not a bad run and longer than say the Super Connie, Vanguard, DC-8-40, CL-65 and 747-400. And ... only a few years shy of the 727!

longhauler wrote:

BravoOne wrote:

I'm not saying the A330 was the cause of this accident but rather pilot would have had a better chance at recovery had he been in a Boeing. Sorry if that bothers you. Sometimes the facts hurt.

And Asiana 214 would not have happened in (any) Airbus right back to the old A300 designed in the early 1970s.

For the record, the solution of both incidents is better training. High altitude full stall detection and recovery is now a part of training. (It was not trained before AF447). It is very eye opening to see exactly how much altitude is lost during the recovery of such an event!

Asian 214 was pure pilot stupidity. I'm well familiar with the system and what occurred. No way can you blame the Boeing design for that. They were on approach and they set the Autoflight System to climb to their MCP missed approach altitude; then manually overrode it. Then they didn't monitor their airspeed.

If you want to bring up stuff like that, the TAM A320 accident in Sao Paulo wouldn't have happened in any Boeing right back to the old 707 designed in the mid-1950s. Wasn't there a runway overrun in WAW on an A320 with two fatalities that also occurred because the systems overrode pilot input, which would not have occurred on any Boeing airplane?

BoeingGuy wrote:

Asian 214 was pure pilot stupidity. I'm well familiar with the system and what occurred. No way can you blame the Boeing design for that. They were on approach and they set the Autoflight System to climb to their MCP missed approach altitude; then manually overrode it. Then they didn't monitor their airspeed.

I didn't blame Boeing design for the loss of Asiana 214, I merely said that it would not have happened in an Airbus.

And, it was a training issue with regard to AF447, (much like OZ214). I do agree that it was less likely to happen in a Boeing, but it is even less likely to happen today in either Boeing or Airbus, as I mentioned before, full stall recognition and recovery is now a part of training where it was not before.

With regard to the other accidents you mention, just like a lot of Boeing accidents, they really boil down to not being properly trained (like OZ214) and not fully understanding how, when and if the automation is going to work.

WPvsMW wrote:

"freight cans" Reminded me of this chestnut.
viewtopic.php?f=5&t=757033&p=10919033&hilit=%22freight+cans%22#p10919033

Yup, you just can't make that stuff up. We had a mech that had a habit of anytime he got around Skydrol hydraulic fluid he managed to bathe his eye with it.

To me the extraordinary thing is not the qualities of the MAX family or the NEO family but what the combined sales of the two families are!Both planes are phenomenal and (partly) as a result the short/mid range market appears to be exploding right around the World.
I find it hard to get my head around the future production rates of both aircraft.They are banging them out as if they were cars!One must assume that all the time the cost to build goes down and down a real virtuous circle.
Slot space at airports must ( as a result of this continued expansion) be increasingly constrained so one assumes we will see the larger models (7310 and 321) do better and better over time.
To answer the threadstarter.I am not sure it really matters which one you choose as long as you get a cracking deal.You can't really put a sheet of paper between them on performance until you get to the longer ranges (A321neo LR/LRX).Boeing don't have a model in this sector so it's not a competition -yet.

Sometimes, a decision comes down to when lease payments are due and how those interact with the customer's tax schedule.

wave46 wrote:

I too was surprised when Air Canada chose the 737, given its history and familiarity with the A320 (since the '80s!). Boeing must've made a heck of an offer to offset the cost of retraining pilots.

Close, but not quite the 80s. First delivery in Jan 1990. I will concede they were ordered in the '80s, but they weren't in service until the 90s.

Just sayin'

Well I guess this question just got more complicated

BoeingGuy wrote:

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

In the A320 into the trees accident, the aircraft was flown into an unrecoverable low energy situation by the crew. If pilot inputs to pull up further had been followed, the accident would likely have been much worse. As it was, FBW delivered maximum performance and prevented a stall. Unfortunately, enough performance to avoid ground impact was not available given the low energy state.

in the WAW accident, the primary cause was lack of information about windshear given by tower, and incorrect flight crew decisions.

If pilots insist on making unwise decisions, there's only so much an aircraft can do to keep them out of trouble.

Starlionblue wrote:

BoeingGuy wrote:

zeke wrote:

Seems to perform better at taking out brick walls or runway excursions. Not as good floating.

You mean like the A320 that flew into the trees or LH A320 that ran off the end of the runway at WAW because they ignored pilot control inputs, something a Boeing airplane would never do.

In the A320 into the trees accident, the aircraft was flown into an unrecoverable low energy situation by the crew. If pilot inputs to pull up further had been followed, the accident would likely have been much worse. As it was, FBW delivered maximum performance and prevented a stall. Unfortunately, enough performance to avoid ground impact was not available given the low energy state.

in the WAW accident, the primary cause was lack of information about windshear given by tower, and incorrect flight crew decisions.

If pilots insist on making unwise decisions, there's only so much an aircraft can do to keep them out of trouble.

As a design engineer, I agree with the stall protection intent and disagree with the implementation because of tolerances. If the actual stall speed (without protections) was say 100 knots, what do you think the software engineers would have set the protection speed at....100.1? No, they would allowed a margin to take into account initial tolerances on pitots, temp probes, AOA sensors, and every other piece of hardware involved in the calculation. Then would have allowed for aging, mounting tolerances, temperature effects, etc. All of these occur before the calculations enter the digital part and are more precise. The same tolerances and limit decisions would apply to the maximum bank angle and other protections.

The issue of how to handle tolerances often comes down to "do we add all the tolerances in the safe direction or do we RSS them" as usually they don't all go the same way. The safe way is usually to add them, but that means that the pilot could always get closer to the limits if he were allowed to do so. That's why I think that the Boeing approach is better ... clearly show the pilot the limit, but then allow him/her to exceed it.

The "flying into the trees" accident was clearly the pilots fault for getting into the situation in the first place, but can you really say the plane would have stalled if he had been able to raise the nose a half degree more? I just don't think that creating a "soft accident" is better than no accident at all.

I think the tolerance between ValphaMax and Vstall is there because if get right up against the stall, you won't be able to manoeuvre, plus you won't have any margin in case of gusts.

I don't agree that the Boeing method is better. Different, but not better. In a hypothetical situation where you need maximum performance, for example pulling up to avoid terrain, in an Airbus all you need to do is move the thrust levers to TOGA and pull back fully on the stick. The aircraft will automatically take you to max lift and there is no risk of a stall. In a Boeing you have to carefully pull right back to the stick shaker and continually adjust due to changing load factor. Much more workload and room for error.

In the case of the Mulhouse/Habsheim crash, they were far beyond any chance of saving the aircraft. An extra half degree would not have helped.

Stall speed isn't changed by the protections. AoA is the only factor in a stall. If load factor increases, for example in a level turn at constant speed, AoA increases and stall margin decreases. You can ValphaProt and ValphaMAx moving up and down on the speed tape as load factor changes. ValphaProt and ValphaMax are dynamically calculated and in case they are calculated as follows:

Vα MAX = Vc x √(α-α0)/(αMAX-α0)
Vα PROT = Vc x √(α-α0)/(αPROT-α0)

Where:
α0 is the AOA for a Lift Coeffi cient (CL) equal to 0.
VC is the calibrated airspeed (CAS)
α is current AOA

Source: https://www.airbus.com/content/dam/corp ... ine_21.pdf