There is a an a.net longevity myth regarding the 737 compared to the A320 family aircraft.

If we look at the Leeham article: Pontifications: The Airbus-Boeing chess game

We find a statistic.

frames in service: A320 family 7679 and 737 family 7587
frames delivered: A320 family 8029 and 737 family 9930

Than I do my calculations:

Delivered frames up to 1988 A320 family 16 and 737 1650.

If we now deduct the frames delivered 1988 and earlier we will see A320 family 8029 - 16 = 8013 and 737 9930 - 1650 = 8280 delivered 1988 and later.
I make the assumption that most of the pre 1988 delivered frames are out of service.

Than we can compare frames delivered after 1988 with frames in service:
A320 family 8013 delivered and 7679 in service. 95.83 % in service
737 8280 delivered and 7587 in service. 91.63 % in service

That is not a perfect statistic one would have to compare year by year and sum up. But those numbers hardly point to A320 family aircraft have on average a lower longevity than 737 aircraft. I would explain the higher percentage for the in service A320 family aircraft with the 737 having slightly higher delivery numbers earlier in the 1988 to 2017 time period and the A320 family having slightly higher delivery numbers later in that period.

"slightly higher delivery numbers" is an understatement. In the 5 years after 1988, it was 417 A320 to 905 B737, well over double.

You're including 1125 737-100s and 200s designed and built before the 320 was a twinkle in the designers eye. Yet there are still some of those sturdy little work horses roaming the skies.

And the poinnt is at the end of the day ?

Keep in mind a good portion of those deliveries post 1988 were 737 classics. While they're good airplanes, there's a reason the 737/A320 parity was only really achieved with the introduction of the 737NG. 737 Classic fleets have been retired en masse from most first line operators (BA, UA, WN, KL, US etc.) which is likely what's making that difference.

As well, early 320's have mostly come to the end of their lives as well. the -100's have all been retired, and a lot of older frames have been scrapped. However - a good number of early frames are still with their original operators (AC and LH both operate double digit MSN's)

A more apt comparison would be how many A320's of the same vintage have been scrapped compared to 737NG's(Even that's not a great comparison, as 320's were rolling off the lines, more or less the same, whilst Boeing was overlapping Classics and NG's). However, you can't get a full picture from any of that info, as plenty of perfectly good 737's and A32X's have been scrapped because they're worth more as parts - nothing to do with the longevity of the plane.
For example, AC's C-FDQQ (MSN 59, delivered January 1990) is still flying daily, while other much newer MSN's have been scrapped.
Meanwhile, 3 former Easyjet 737-700's delivered in 2004 met the axeman in 2011.
Similarly, Frontier was scrapping A318's at less than 4 years of age. Nothing wrong with the aircraft, just that the economic reality was that they were worth more as parts to support the rest of the A32X fleet than as serviceable airplanes.

Point of this post? There's so many factors that go into whether an aircraft goes through HMV or meets the scrapman's torch. Very little of it has to do with the aircraft itself (unless it's coming up on some hours/cycles limits requiring crazy amounts of work, or has corrosion issues etc) and much more has to do with dollars and cents.

Yeah, I really don't get the point of this thread either......is there really an a.net myth about the longevity of individual 737 frames versus A320 frames? I've never seen that anywhere......are you confusing it with "longevity" in relation to the fact that the 737 family has been around since the mid 60s and keeps getting a fresh lease of life with each new generation of 737? That's a very different story altogether.....

jupiter2 wrote:

You're including 1125 737-100s and 200s designed and built before the 320 was a twinkle in the designers eye. Yet there are still some of those sturdy little work horses roaming the skies.

737-100 and -200 are not declared to being low on longevity:

And I excluded those frames. I excluded all 737-100 and 737-200, and all 737-300, 737-400 and 737-500 build before 2018. If we include those frames the percentage of frames in service compared to the number of frames delivered gets lower for the 737.

diverted wrote:

Keep in mind a good portion of those deliveries post 1988 were 737 classics. While they're good airplanes, there's a reason the 737/A320 parity was only really achieved with the introduction of the 737NG. 737 Classic fleets have been retired en masse from most first line operators (BA, UA, WN, KL, US etc.) which is likely what's making that difference.

As well, early 320's have mostly come to the end of their lives as well. the -100's have all been retired, and a lot of older frames have been scrapped. However - a good number of early frames are still with their original operators (AC and LH both operate double digit MSN's)

A more apt comparison would be how many A320's of the same vintage have been scrapped compared to 737NG's(Even that's not a great comparison, as 320's were rolling off the lines, more or less the same, whilst Boeing was overlapping Classics and NG's). However, you can't get a full picture from any of that info, as plenty of perfectly good 737's and A32X's have been scrapped because they're worth more as parts - nothing to do with the longevity of the plane.
For example, AC's C-FDQQ (MSN 59, delivered January 1990) is still flying daily, while other much newer MSN's have been scrapped.
Meanwhile, 3 former Easyjet 737-700's delivered in 2004 met the axeman in 2011.
Similarly, Frontier was scrapping A318's at less than 4 years of age. Nothing wrong with the aircraft, just that the economic reality was that they were worth more as parts to support the rest of the A32X fleet than as serviceable airplanes.

Point of this post? There's so many factors that go into whether an aircraft goes through HMV or meets the scrapman's torch. Very little of it has to do with the aircraft itself (unless it's coming up on some hours/cycles limits requiring crazy amounts of work, or has corrosion issues etc) and much more has to do with dollars and cents.

Point of my post was that you will not find numbers that show 737 to be kept longer in service than same age A320, something that has been declared time and time again here on A.net.

I was told that the Airbuses have major corrosion issues as they get up in age, and simply weren’t built to last as some airlines want to ulilize them for. I was told this by a maintenance supervisor at UA.

And he prefers working on the Airbus over 737s. He was adamant that Boeing is built more ‘sturdy.’

Life: Airbus A320 60,000 cycles/120,000 hours, but first builds were 48,000 cycles/60,000 hours.
The A320-100 are being scrapped on that early life.

737NG: 85,000 cycles to a *very* expensive inspection that as far as I know none will pass, 125,000 hours
http://www.boeing.com/commercial/aeroma ... ticle2.pdf

Yes, the above link allows a very expensive repair to take the 737 to 100,000 cycles.

So the life span of the latest versions is very typical as IIRC narrowbodies now fly 2 hours per cycle on average. So the A320s will be retired at 120,000 cycles, 737s could go to 125,000.

Neither is short longevity. Since today's money is expensive and tomorrow's is cheap, no airline is going to select which to buy off a 5,000 hour difference in life to get one or so more years of service 25 to 30 years from now.

Lightsaber
Late edits: Boeing 737s are serviced on a 75,000 cycle life.
I wasn't able to find the FAA information for the A320, but the minimum LOV life is the certified life (which is what maintenance intervals are based off of).

splitterz wrote:

I was told that the Airbuses have major corrosion issues as they get up in age, and simply weren’t built to last as some airlines want to ulilize them for. I was told this by a maintenance supervisor at UA.

And he prefers working on the Airbus over 737s. He was adamant that Boeing is built more ‘sturdy.’

Exactly, the myth, not backed up by numbers.

Gr8Circle wrote:

Yeah, I really don't get the point of this thread either......is there really an a.net myth about the longevity of individual 737 frames versus A320 frames? I've never seen that anywhere......

No, there isn't. I read a here a lot, and "something that has been declared time and time again here on A.net" has flown under my radar.

Gr8Circle wrote:

are you confusing it with "longevity" in relation to the fact that the 737 family has been around since the mid 60s and keeps getting a fresh lease of life with each new generation of 737? That's a very different story altogether.....

I hope so.

Besides blowing the Airbus fan boy trumpet, what is the point of the post ?

Lightsaber has given the only numbers that matter. Do your numbers take into account bankruptcies, write offs, cheap new builds, spares worth, acts of terrorism, wars, take overs and mergers, etc ?

lightsaber wrote:

Life: Airbus A320 60,000 cycles/120,000 hours, but first builds were 48,000 cycles/60,000 hours.
The A320-100 are being scrapped on that early life.

737NG: 85,000 cycles to a *very* expensive inspection that as far as I know none will pass, 125,000 hours
http://www.boeing.com/commercial/aeroma ... ticle2.pdf

Yes, the above link allows a very expensive repair to take the 737 to 100,000 cycles.

So the life span of the latest versions is very typical as IIRC narrowbodies now fly 2 hours per cycle on average. So the A320s will be retired at 120,000 cycles, 737s could go to 125,000.

Neither is short longevity. Since today's money is expensive and tomorrow's is cheap, no airline is going to select which to buy off a 5,000 hour difference in life to get one or so more years of service 25 to 30 years from now.

Lightsaber
Late edits: Boeing 737s are serviced on a 75,000 cycle life.
I wasn't able to find the FAA information for the A320, but the minimum LOV life is the certified life (which is what maintenance intervals are based off of).

Thanks for this. Putting on my armchair mod hat, now would be a good time to lock this pointless thread.

Bricktop wrote:

lightsaber wrote:

Life: Airbus A320 60,000 cycles/120,000 hours, but first builds were 48,000 cycles/60,000 hours.
The A320-100 are being scrapped on that early life.

737NG: 85,000 cycles to a *very* expensive inspection that as far as I know none will pass, 125,000 hours
http://www.boeing.com/commercial/aeroma ... ticle2.pdf

Yes, the above link allows a very expensive repair to take the 737 to 100,000 cycles.

So the life span of the latest versions is very typical as IIRC narrowbodies now fly 2 hours per cycle on average. So the A320s will be retired at 120,000 cycles, 737s could go to 125,000.

Neither is short longevity. Since today's money is expensive and tomorrow's is cheap, no airline is going to select which to buy off a 5,000 hour difference in life to get one or so more years of service 25 to 30 years from now.

Lightsaber
Late edits: Boeing 737s are serviced on a 75,000 cycle life.
I wasn't able to find the FAA information for the A320, but the minimum LOV life is the certified life (which is what maintenance intervals are based off of).

Thanks for this. Putting on my armchair mod hat, now would be a good time to lock this pointless thread.

“Pointless” in the eye of a Boeing enthusiast?

Just remember that the 737 was created to compete against the DC-9 and not the A320. Neither the 737 or the 320 can hold a candle to the 9 for ruggedness or durability.

Is it because early 737s were less tech, like MKIV Jettas and very old Merc Diesels which run forever, just enough electronics to monitor the health or major components, but not a maintenance money pit like latest ones loaded with sensors.

The A320 was originally designed for 48,000 cycles
The 737NG was originally designed for 75,000 cycles

The original design life’s are not myths. They are on the FAA website:

https://www.gpo.gov/fdsys/pkg/FR-2010-1 ... -28363.htm


A300 B2 Series 48,000 FC
A300 B4-100 40,000 FC
A300 B4-203 34,000 FC
A300-600 30,000 FC/67,500 FH
A310-200 40,000 FC/60,000 FH
A310-300 35,000 FC/60,000 FH
A318 48,000 FC/60,000 FH
A319 48,000 FC/60,000 FH
A320-100 48,000 FC/48,000 FH
A320-200 48,000 FC/60,000 FH
A321 48,000 FC/60,000 FH
A330-200, -300 40,000 FC/60,000 FH
A340-200, 300 20,000 FC/80,000 FH
A340-500, 600 16,600 FC/100,000 FH
717 60,000 FC/60,000 FH
727 60,000 FC
737 737-100, -200 200C, -300, -400, -500 75,000 FC
737 (NG): 737-600, -700, -700C, 75,000 FC
737-900ER.75,000 FC
747 20,000 FC
757 50,000 FC
767 50,000 FC
777-200, -300 40,000 FC
777-200LR, 777-300ER 40,000 FC

Here is some information on damage tolerant designs as they relate to fatigue and structural design:

http://www.boeing.com/resources/boeingd ... s_full.pdf

The A320 has had service life extensions, so it is not limited to 48,000 cycles. As all airplanes age, maintenance costs go up. Service life extensions allow an airplane to fly longer but come at the cost of more maintenance inspections, repairs or replacements of life limited components and structurally related airworthiness directives. For example early 767s require the aft pressure bulkhead to be replaced before 50,000 cycles, which is incredibly expensive.

The original design life is important for reliability of systems components. Lab testing typically covers a number of cycles depending on design life. For flight control actuators for example, they are typically tested 4 times design life during the certification process. That means a flight control actuator on an A320 would have gone through 192,000 flight cycles in lab testing during certification whereas a 737 actuator would have gone through 300,000 flight cycles. The design specifications given to suppliers have design life’s and they design components for those lives. A component designed for a lower number of cycles may be lighter or cheaper, but also more likely to fail as Service lives get extended.

Here is some reading on the certification process

https://www.faa.gov/aircraft/air_cert/d ... _guide.pdf

I won’t make any definitive conclusion on which plane has more longevity. The operating environment and conditions as well as maintenance have impacts. Avoiding saltwater and dust/desert will extend an airplanes life better than any maintenance program. With all that said, original design lives do affect durability and longevity, but maintenance costs still can be excessive.

nikeherc wrote:

Just remember that the 737 was created to compete against the DC-9 and not the A320. Neither the 737 or the 320 can hold a candle to the 9 for ruggedness or durability.

Exactly. My father worked in engineering and flight test for UA in the late '60s, and has a degree in aeronautical engineering. He also flew the line for UA for 20 years after that.

He always said Douglas built a more rugged airplane.

birdbrainz wrote:

nikeherc wrote:

Just remember that the 737 was created to compete against the DC-9 and not the A320. Neither the 737 or the 320 can hold a candle to the 9 for ruggedness or durability.

Exactly. My father worked in engineering and flight test for UA in the late '60s, and has a degree in aeronautical engineering. He also flew the line for UA for 20 years after that.

He always said Douglas built a more rugged airplane.

The design life for a DC9 is 100,000 cycles. A 737 is 75,000 cycles. An A320 is 48,000 cycles. It is not a fallacy that DC9 was designed for more cycles and I think the engineering substantiates the reputation for ruggedness.

marcelh wrote:

Bricktop wrote:

lightsaber wrote:

Life: Airbus A320 60,000 cycles/120,000 hours, but first builds were 48,000 cycles/60,000 hours.
The A320-100 are being scrapped on that early life.

737NG: 85,000 cycles to a *very* expensive inspection that as far as I know none will pass, 125,000 hours
http://www.boeing.com/commercial/aeroma ... ticle2.pdf

Yes, the above link allows a very expensive repair to take the 737 to 100,000 cycles.

So the life span of the latest versions is very typical as IIRC narrowbodies now fly 2 hours per cycle on average. So the A320s will be retired at 120,000 cycles, 737s could go to 125,000.

Neither is short longevity. Since today's money is expensive and tomorrow's is cheap, no airline is going to select which to buy off a 5,000 hour difference in life to get one or so more years of service 25 to 30 years from now.

Lightsaber
Late edits: Boeing 737s are serviced on a 75,000 cycle life.
I wasn't able to find the FAA information for the A320, but the minimum LOV life is the certified life (which is what maintenance intervals are based off of).

Thanks for this. Putting on my armchair mod hat, now would be a good time to lock this pointless thread.

“Pointless” in the eye of a Boeing enthusiast?

Pointless in the sense that it adds zero value to the community, IMO. Lightsaber gave numbers that there's virtually no evidence of a difference in lifespans.
Are Airbus fanboys so insecure that they need constant reassurance and affirmation? It is only in their minds that any even mild criticism of their binky is worthy of such strawman threads.

I was waiting for a 737 vs A320 thread to open to ask this question as I didnt want to start a massive heated debate.

On the same route, same leasing rates, 100% LF, same fuel costs, same wages for pilots and staff, same landing fees etc etc - does anyone know which of the A320Neo vs 737Max is better in terms of revenue and efficiency?

Bricktop wrote:

marcelh wrote:

Bricktop wrote:

Thanks for this. Putting on my armchair mod hat, now would be a good time to lock this pointless thread.

“Pointless” in the eye of a Boeing enthusiast?

Pointless in the sense that it adds zero value to the community, IMO. Lightsaber gave numbers that there's virtually no evidence of a difference in lifespans.
Are Airbus fanboys so insecure that they need constant reassurance and affirmation? It is only in their minds that any even mild criticism of their binky is worthy of such strawman threads.

Actually, most “fanboys” are that insecure, regardless of persuasion.

That said, I’d say this thread is pointless in the eyes of those that tire of all these straw man arguments designed to “prove” something folks weren’t really arguing in the first place.

Any topic that needs to rely on “a.net myths” (or a.net popular wisdom or whatever of the sort) falls into this category, whether it’s done to “prove” that A320s do or don’t have long service-life potential, or to “prove” that the 787 is or is not making Boeing any money today, or to “prove” that four-engined airplanes are or are not impossible to operate profitably.

Bricktop wrote:

marcelh wrote:

Bricktop wrote:

Thanks for this. Putting on my armchair mod hat, now would be a good time to lock this pointless thread.

“Pointless” in the eye of a Boeing enthusiast?

Pointless in the sense that it adds zero value to the community, IMO. Lightsaber gave numbers that there's virtually no evidence of a difference in lifespans.
Are Airbus fanboys so insecure that they need constant reassurance and affirmation? It is only in their minds that any even mild criticism of their binky is worthy of such strawman threads.

Stop being such a child over something so silly on an internet forum.

mjoelnir wrote:

Than we can compare frames delivered after 1988 with frames in service:
A320 family 8013 delivered and 7679 in service. 95.83 % in service
737 8280 delivered and 7587 in service. 91.63 % in service.

Not to start a troll-war or anything, but the primary factor here (as I see it) is that in the late 80's, as the 320 was introduced, it was a DRAMATIC advancement on the original 737 models. It took Boeing nearly a decade to get a competing product (NG) out and certified, flying, produced in numbers, etc.. I think that decade really saw a huge shift in sales.

Likewise, those 320s sold early on had a significantly longer life expectancy than the -100s and -200 floating around. During that span and the 90s the numbers became fairly skewed (there was a span when it was ridiculous to buy a -200 when the 320 was out with FBW, modern aerodynamics, high bypass engines, etc).

So, those 320s stuck around for a LONG TIME meanwhile the oldest 737s you'll see are NGs which are automatically 10+ years newer.

I know there are exceptions to what I'm saying, but I'm just doing the basic math to figure out why you see the numbers you do while the 737 was produced in much larger numbers.

Obviously today we are seeing things change again, and the 737 fuselage just doesn't have much life left in it. You'll likely see that 10 year intro gap equate into about a two-decade-longer sales-life of the 320 over the 737 eventually. A lot was changing back in the mid-80s development-wise.

Doesn't that perception of Airbus being less sturdy than Boeing also come from an evolution in accounting practices and assets management in Airlines (leasing etc...) more than from the technology itself?
The first 737's and DC9's were introduced at a time when companies were willing to put lots of maintenance in their planes to keep them airworthy and protect their capital. But at that time, labour, fuel and spare parts wouldn't weight so much as today. The A320 family came in much later than the classic 737's, at a time where leasing was becoming more common and where airlines are also on a faster replacement cycle in the race for being the most competitive (change to a new type to benefit from lower fuel consumption and appear "greener"). Many planes axed recently could still perfectly fly but used too much fuel or were simply too much worth as spare parts to keep them flying...

I’ve never seen or heard of this “a.net myth”.

The gentleman doth protest too much, methinks.

WN just retired the -300 fleet about 6 months ago right .. so mabe this project needs to be redone in 5 years.. to get a fair assessment

WN is retiring oldest operating 737s, if I understand correctly, because FAA says pilots should not be operating 3 different flight systems. Obsolescence can come from many directions.

As this thread is turning is already going off topic, I.e. posters are more interested in faming the other side rather than discuss the topic, thread will be locked