Gonzalo
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How Long Is The Lifespan Expected For A380/B787

Fri Oct 21, 2011 11:26 pm

Hi All. After watching some pictures of B727 / DC-8F still active and healthy, I have some questions, I hope you can give me your opinions..
Is there any estimate for the expected lifespan for this new models of Airbus ( A380 and maybe the A350) and Boeing ( 787) ?
Are this expectations affected for the extensive use of composite materials in those models ?
How different are this expectations compared with an aircraft with less composites in the main structure ( Aluminum aircraft ) ?


Thanks !!

Rgds.
G.
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Centre
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 1:20 am

Life expectancy is mostly dependent on cycles.... Considering the aforementioned aircrafts are long-haul ones (long sectors and long down times on the ground waiting for the return flight), they should be fine for 20+ years.
Exceptions are EK and SQ... Aircrafts wont last that long in their colors  .
I have cut 4 times, and it's still short.
 
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Stitch
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 1:20 am

Composites are expected to increase the usable lifespan of an airframe, so they should lboth last scores of years, I would expect.
 
jben
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 7:39 am

For the A380, Airbus has tested the airframe out to 47,500 cycles (http://www.airbus.com/company/aircraft-manufacture/how-is-an-aircraft-built/test-programme-and-certification/). For the A320, Airbus announced a program back in 2008 to extend the airframe life to 120,000 flight hours.

This story about the 787 (http://www.aviationweek.com/aw/generic/story.jsp?id=news/awx/2010/09/13/awx_09_13_2010_p0-254245.xml&headline=Fatigue%20Tests%20Begin%20on%20787&channel=comm) mentions that for the design it is for 44,000 cycles, with the fatigue airframe they are going to 165,000 cycles.

For aircraft, particularly lately, planes are retired a long time before they reach their cycle limit. A point is reached where it costs more to maintain the aircraft than the financing costs of a new aircraft.

For some aircraft with no replacement, the manufacturer will develop a life of type extension to prolong service life, replacing large parts of the aircraft such as the main barrel, wing box, engines, avionics and other parts. If you have the money, you can keep an aircraft flying pretty much indefinitely. Just think of the Basler BT-67. It's a DC-3, the last of which rolled off the production line in 1942. It's a completely upgraded airframe though and is basically a new aircraft. A better example is the B-52, if the USAF retires them when they expect to (after 2045), the airframe will be over 90 years old.

[Edited 2011-10-22 00:44:31]
 
474218
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 3:40 pm

Quoting jben (Reply 3):
For the A380, Airbus has tested the airframe out to 47,500 cycles ...
This story about the 787 ... mentions that for the design it is for 44,000 cycles, with the fatigue airframe they are going to 165,000 cycles.

This story ... about the 787 mentions that for the design it is for 44,000 cycles, with the fatigue airframe they are going to 165,000 cycles.

The standard procedure is to take the number of fatigue test cycles achieved and divide that number in half, ie 47,000 test cycles would lead to a operational life of 23,500 cycles. A design life of 44,000 cycles would have required 88,000 fatigue test cycles. However, this does not mean the aircraft is worn out at 23,500 or 44,000 cycles, that is the point where the manufacture and operator must have in place a program (service bulletins/maintenance plans) that can be accomplished that will extend that life.

Quoting jben (Reply 3):
A better example is the B-52, if the USAF retires them when they expect to (after 2045), the airframe will be over 90 years old.

The B-52's that will be operation in 2045 were built between 1960 and 1962. So they will be about 85 years old. Additionally, the military does not put the hours and cycles on their aircraft airlines do. The C-17 was designed to operate 1,000 hours a year while a civilian airline operates about 3,000 hours a year.
 
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Moose135
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 5:11 pm

Quoting 474218 (Reply 4):
The B-52's that will be operation in 2045 were built between 1960 and 1962. So they will be about 85 years old.

It's not your father's Air Force, but it might be your grandfather's airplane...

Quoting 474218 (Reply 4):
Additionally, the military does not put the hours and cycles on their aircraft airlines do. The C-17 was designed to operate 1,000 hours a year while a civilian airline operates about 3,000 hours a year.

But does the type of flying make a difference? Not too many civilian jetliners performing low level missions, or dropping into unimproved airstrips.
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dynamicsguy
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 10:30 pm

Quoting Stitch (Reply 2):
Composites are expected to increase the usable lifespan of an airframe, so they should lboth last scores of years, I would expect.

Their structures are still full of metal parts, including all of the fasteners holding the composites together, so scores of years is optimistic for an economical lifetime.

Quoting 474218 (Reply 4):
The standard procedure is to take the number of fatigue test cycles achieved and divide that number in half

At Boeing the design requirement is 3x the design service objective.
 
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 11:14 pm

Quoting dynamicsguy (Reply 6):
At Boeing the design requirement is 3x the design service objective.

Must be some thing new?

http://www.boeing.com/news/releases/1997/news.release.970317a.html
 
wn700driver
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 22, 2011 11:50 pm

Quoting moose135 (Reply 5):

But does the type of flying make a difference? Not too many civilian jetliners performing low level missions, or dropping into unimproved airstrips.

No, it really doesn't. At least not for the B-52. Flying low does provide a lot of buffeting issues to be sure, but there are two things to remember there... They don't actually fly low for anything like the majority of a given mission, and when they do, the fatigue involved with that is more than balanced by the fact that they're not pressurized (in the cabin spaces) during that phase of the mission.

Also there are other factors to consider as well. Not too many airliners have TBOs as short as B-52s, not too many B-52s have to deal with being into tight ramp corners where casual skin damage occurs most; they also don't land on short runways or deal with noise abatement procedures. Plus their components are typically replaced a great deal more often than civilian aircraft have to live with. Also, they don't carry cargo close to their operational limits very often either.

These planes are warriors in name only. The truth is that they are actually coddled very well compared to their civilian counterparts.

I should think that a good comparison (operationally I mean) would be more like the life of a DC-10 vs KC-10. You don't have a lot of technical or parts differences between the two, so what the conditions of one vs the other are will be based only on ops. I'm relatively certain that the KC-10s are in much better shape, age per age.
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RE: How Long Is The Lifespan Expected For A380/B787

Sun Oct 23, 2011 1:59 am

Quoting 474218 (Reply 7):
Must be some thing new?

Interesting. For the 787 it is definitely 3x DSO. I had assumed that this was an example of Boeing setting design requirements above the certification requirements as I know of quite a few other instances of this. Maybe this is a response to the tendency of operators to fly airplanes beyond their nominal DSO.

I'll have to dig into the design manuals on Monday.
 
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RE: How Long Is The Lifespan Expected For A380/B787

Sun Oct 23, 2011 2:04 am

Quoting wn700driver (Reply 8):
These planes are warriors in name only. The truth is that they are actually coddled very well compared to their civilian counterparts.

Well, except for that part where they get shot at...  
KC-135 - Passing gas and taking names!
 
474218
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RE: How Long Is The Lifespan Expected For A380/B787

Sun Oct 23, 2011 3:15 am

Quoting dynamicsguy (Reply 9):

Interesting. ... I'll have to dig into the design manuals on Monday.

Using 50% has been standard for years, but maybe with these new "plastic" airplanes who knows.

Please let us know!
 
BE77
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RE: How Long Is The Lifespan Expected For A380/B787

Sun Oct 23, 2011 3:23 pm

Quoting jben (Reply 3):
a DC-3, the last of which rolled off the production line in 1942
http://www.ruudleeuw.com/skytrain.htm
http://www.boeing.com/history/chronology/chron06.html
I seem to always recall it was May 1944 (ie the month before D-Day). These two pages infer production into 1945, the first quoting 45- serial numbers, the second talking about delivery (which of course is not the same as production, but it seems odd a gooney would be built and not be delivered for 3 years in that particular era). I'm sure there's a better doc somewhere - just all I could quickly find.

Quoting moose135 (Reply 5):
but it might be your grandfather's airplane.

Hmm - 20 year old crewman in 1960, with newborn, who is 20 in 1980, who's kid is 20 in 2000, then 2020, then 2040.
Is that your Great Great Grandfathers airplane?   

Quoting wn700driver (Reply 8):
The truth is that they are actually coddled very well compared to their civilian counterparts
Quoting moose135 (Reply 10):
Well, except for that part where they get shot at

Agree - I think if I was going to be counting on something when someone else was shooting at me, I would coddle it as much as possible up until that point...at which time it is going to be excessively abused, but the boss is probably expecting to have to replace a few airframes anyway. (How did that line go...up until the release point, you're flying for your country, after, you fly for yourself?).
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RE: How Long Is The Lifespan Expected For A380/B787

Mon Oct 24, 2011 9:58 am

Quoting Gonzalo (Thread starter):
After watching some pictures of B727 / DC-8F still active and healthy

Is it fair to say that the B727 and DC-8 and other aircraft of that era flew a lot less than modern aircraft do today, thus they have less wear and fewer cycles and can fly for many more years still? This making these aircraft unique, as newer aircraft are worked much harder and simply scrapped when they reach a certain number of cycles...?

The DC-8-63 has become a great freighter aircraft, but I assume they flew a less demanding schedule as a pax airliner in the 1960s-1980s than the B767/777/747 and A330/340 do today. Many flights were not daily and they had longer ground stops.
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jben
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RE: How Long Is The Lifespan Expected For A380/B787

Mon Oct 24, 2011 10:15 am

Basically all production between 1942 and August 1945 was for the military C-47 and variants. I was actually mistaken though, after the war, the final DC-3 delivery was actually delivered in March 1947.

My bad!

Quoting BE77 (Reply 12):
Quoting jben (Reply 3):
a DC-3, the last of which rolled off the production line in 1942
http://www.ruudleeuw.com/skytrain.htm
http://www.boeing.com/history/chronology/chron06.html
I seem to always recall it was May 1944 (ie the month before D-Day). These two pages infer production into 1945, the first quoting 45- serial numbers, the second talking about delivery (which of course is not the same as production, but it seems odd a gooney would be built and not be delivered for 3 years in that particular era). I'm sure there's a better doc somewhere - just all I could quickly find.
 
Rara
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RE: How Long Is The Lifespan Expected For A380/B787

Mon Oct 24, 2011 3:02 pm

The day will come that some obscure African airline will pick up an old and decrepit A380 and use it to tirelessly shuttle people around intra-African routes.   And on that day, everyone who reads this now will suddenly feel very old.   
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RE: How Long Is The Lifespan Expected For A380/B787

Mon Oct 24, 2011 5:15 pm

For perspective, manufacturers expect to support a new airframe 30 to 40 years after EIS.

Quoting Stitch (Reply 2):
Composites are expected to increase the usable lifespan of an airframe, so they should lboth last scores of years, I would expect.

Plus the metal parts are of better alloys or with superior coatings.

I suspect today's airframes will be retired on fuel burn. I'm not betting long term on cheap oil.   

Quoting jben (Reply 3):
For aircraft, particularly lately, planes are retired a long time before they reach their cycle limit. A point is reached where it costs more to maintain the aircraft than the financing costs of a new aircraft.

Agreed. But if the plane is converted to a freighter, the maintenance burden is less. Freighters also 'stop clock' the airframe to minimize the C and D checks. HA does that with their 717s during the slow season too.

Quoting moose135 (Reply 5):
It's not your father's Air Force, but it might be your grandfather's airplane...

We have B-52s being flown by grandchildren of prior B-52 pilots.

Lightsaber
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RE: How Long Is The Lifespan Expected For A380/B787

Mon Oct 24, 2011 8:16 pm

Quoting lightsaber (Reply 16):
I suspect today's airframes will be retired on fuel burn. I'm not betting long term on cheap oil.

I suspect that keeping the "systems" in working order (as opposed to the "structure") constitutes a large part of the economic airowrthiness of an old airframe....

Keeping old systems working gets increasingly difficult, especially if they're so old that the supply chain that begat them and maintains them is falling to pieces

Rgds
 
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RE: How Long Is The Lifespan Expected For A380/B787

Mon Oct 24, 2011 10:17 pm

Quoting lightsaber (Reply 16):
We have B-52s being flown by grandchildren of prior B-52 pilots.

Lightsaber

IIRC, there was a story floating around somewhere about 3 generations of pilots flying the same B-52 over the years. A SAC pilot, then his son during Desert Storm, then his son during the recent conflicts.


I figure every aircraft should get the same cycles/hours/age as a NW DC-9. Just sayin'....  
 
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RE: How Long Is The Lifespan Expected For A380/B787

Thu Oct 27, 2011 7:01 pm

Quoting astuteman (Reply 17):
Keeping old systems working gets increasingly difficult, especially if they're so old that the supply chain that begat them and maintains them is falling to pieces

Very true. That is one reason why products that stay in production a long time are supported a long time (viable supply chain). I use the MD-80 as an example. Due to rapid retirements of the type, the vendors are not moving enough product.   AA has just started pulling MD-80s from service in mass. In 2013, with the A319 deliveries, that accelerates. At that time, I suspect too much of the MD-80 supply chain will disapear.

Quoting trigged (Reply 18):
IIRC, there was a story floating around somewhere about 3 generations of pilots flying the same B-52 over the years. A SAC pilot, then his son during Desert Storm, then his son during the recent conflicts.

I recall reading that too... I wish I had the link.

Quoting trigged (Reply 18):
I figure every aircraft should get the same cycles/hours/age as a NW DC-9.

   You don't set a high bar, now do you.   115k cycles...   

The only two aircraft I'm aware of that sees examples retired within spitting distance of the cycle limit is the DC-9 and 737. (I'm sure I'm about to get a laundry list of other types). Most airframes tend to be retired earlier on economics.

Lightsaber
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trigged
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RE: How Long Is The Lifespan Expected For A380/B787

Thu Oct 27, 2011 8:26 pm

Quoting lightsaber (Reply 19):
The only two aircraft I'm aware of that sees examples retired within spitting distance of the cycle limit is the DC-9 and 737. (I'm sure I'm about to get a laundry list of other types). Most airframes tend to be retired earlier on economics.

With the re-engine program of the KC-135/707 and DC-8 over to the current engines, what was the R&D status with regards to the engine pylons? I figure alot of the tooling is gone now unless there is still a program going on with the re-engining.
 
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RE: How Long Is The Lifespan Expected For A380/B787

Fri Oct 28, 2011 8:21 pm

Quoting trigged (Reply 20):
With the re-engine program of the KC-135/707 and DC-8 over to the current engines, what was the R&D status with regards to the engine pylons? I figure alot of the tooling is gone now unless there is still a program going on with the re-engining.

Cammacorp who re-engined the DC-8 with CFM -56 engines stopped modifying DC-8's in 1986. All tooling has been destroyed. Grumman built the engine pylons.
 
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 29, 2011 8:03 am

Quoting lightsaber (Reply 19):
AA has just started pulling MD-80s from service in mass. In 2013, with the A319 deliveries, that accelerates. At that time, I suspect too much of the MD

Yes. Of course, at the same time the the retired MD-80s will be used for parts... which works well for some parts and not so well for others. Anything that wears out on a regular schedule (e.g., tires, engine components) will still need a supply chain.

Question: which systems have a specified lifetime and must be replaced on a regular schedule? Are cockpit instruments something that can be used forever if they work, for instance?
 
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 29, 2011 8:34 am

Quoting Rara (Reply 15):
The day will come that some obscure African airline will pick up an old and decrepit A380 and use it to tirelessly shuttle people around intra-African routes.

My first reaction is that it almost feel that way already, with AF running dented and probably soon pretty dirty A380s around. And just wait for BA to get theirs, their cabin cleanliness and other standards will make you feel like being "tirelessly shuttled around"  

My second reaction was to think back and make a wish that Concorde had been more widely deployed. If they had manufactured 100+ copies, by now we'd have badly maintained end-of-life Concordes flying for near-bankrupt airlines in countries with shoddy safety standards. If not for anything else, it would have made for exciting adventure possibilities. Think of the a.net trip reports! And Travolta would have one, plus a few ones maintained by local aviation clubs... I can dream, can't I?
 
wn700driver
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RE: How Long Is The Lifespan Expected For A380/B787

Sat Oct 29, 2011 9:58 am

Quoting AirlineCritic (Reply 22):
Are cockpit instruments something that can be used forever if they work, for instance?

To briefly oversimplify, they'd need to stay in calibration.
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