EMBQA From United States of America, joined Oct 2003, 9286 posts, RR: 13 Reply 1, posted (2 years 9 months 3 weeks 2 days 12 hours ago) and read 6913 times:
JBo From Sweden, joined Jan 2005, 2279 posts, RR: 0 Reply 2, posted (2 years 9 months 3 weeks 2 days 11 hours ago) and read 6774 times:
Quoting EMBQA (Reply 1): Aircraft do not have a limited life as long as you continue to maintain them. The life ends when it becomes more expensive to maintain them.
Precisely. However, it is noted that some aircraft were designed and built to withstand a certain number of cycles, beyond which the performance/reliability is not guaranteed.
Some aircraft are built more ruggedly than others, which is why some on this board believe the DC-9 will be the only airworthy aircraft after the apocalypse
I'd take the awe of understanding over the awe of ignorance any day.
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9 Reply 3, posted (2 years 9 months 3 weeks 2 days 10 hours ago) and read 6689 times:
Quoting JBo (Reply 2): Precisely. However, it is noted that some aircraft were designed and built to withstand a certain number of cycles, beyond which the performance/reliability is not guaranteed.
All current passenger aircraft a "design life goal" a specific number of cycles (one takeoff one landing = one cycle). A the time the "design life goal" is attained the manufacture is required to have an approved program that when incorporated will allow the operator to operate the aircraft beyond the "design life goal".
Some operators my choose to remove aircraft from their fleet before the "design life goal" is met to forgo the expense this added maintenance will require. However, many operator will incorporate these modifications and continue to operated the aircraft until they determine that it is no longer cost effective to continue provide the added maintenance required to continue the aircraft's airworthiness.
flyby519 From United States of America, joined Jul 2007, 852 posts, RR: 0 Reply 4, posted (2 years 9 months 3 weeks 2 days 10 hours ago) and read 6646 times:
An idea what the "design life goal" for the ERJ 135/140/145 series is? There are some older ones getting up over 30k cycles.
CanadianNorth From Canada, joined Aug 2002, 3371 posts, RR: 10 Reply 5, posted (2 years 9 months 3 weeks 2 days 10 hours ago) and read 6606 times:
Life limit of most aircraft is, as said, basically the point at which it becomes more expensive to keep it airworthy than it would be to replace it.
Quoting flyby519 (Reply 4): There are some older ones getting up over 30k cycles.
I know it's an apples to rear differentials comparison, but we have a 737 in our fleet still going strong with over 70k cycles (and age doesn't matter nearly as much as some people think, we have several aircraft that are multiple years older than it with significantly less cycles)
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9 Reply 6, posted (2 years 9 months 3 weeks 2 days 9 hours ago) and read 6536 times:
Quoting flyby519 (Reply 4): An idea what the "design life goal" for the ERJ 135/140/145 series is? There are some older ones getting up over 30k cycles.
They were not included as their MTOW is under 75,000 lbs.
atlengineer From United States of America, joined Jul 2010, 72 posts, RR: 0 Reply 7, posted (2 years 9 months 3 weeks 2 days 9 hours ago) and read 6482 times:
If I remember correctly from Widgetheads, some of the Delta DC9-30's and 40's still flying are over 40 years old and have as much as 90,000 hours and/or 70,000 cycles on them. I'm flying PIT/ATL Thursday night on a DC9-50. That plane is probably 35 or more years old.
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9 Reply 8, posted (2 years 9 months 3 weeks 2 days 6 hours ago) and read 6371 times:
Quoting atlengineer (Reply 7): If I remember correctly from Widgetheads, some of the Delta DC9-30's and 40's still flying are over 40 years old and have as much as 90,000 hours and/or 70,000 cycles on them. I'm flying PIT/ATL Thursday night on a DC9-50. That plane is probably 35 or more years old.
The DC-9's Design Life Goal is 100,000 cycles, at 70,000 cycles it has lots of life left.
atlengineer From United States of America, joined Jul 2010, 72 posts, RR: 0 Reply 9, posted (2 years 9 months 3 weeks 2 days 6 hours ago) and read 6348 times:
Quoting 474218 (Reply 8): Quoting atlengineer (Reply 7):
If I remember correctly from Widgetheads, some of the Delta DC9-30's and 40's still flying are over 40 years old and have as much as 90,000 hours and/or 70,000 cycles on them. I'm flying PIT/ATL Thursday night on a DC9-50. That plane is probably 35 or more years old.
The DC-9's Design Life Goal is 100,000 cycles, at 70,000 cycles it has lots of life left.
Thanks 474218. Do you know what the Design Life Goal is for the MD88's and MD90's?
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9 Reply 10, posted (2 years 9 months 3 weeks 2 days 5 hours ago) and read 6284 times:
Quoting atlengineer (Reply 9): Thanks 474218. Do you know what the Design Life Goal is for the MD88's and MD90's?
EMBQA From United States of America, joined Oct 2003, 9286 posts, RR: 13 Reply 11, posted (2 years 9 months 3 weeks 2 days 3 hours ago) and read 6156 times:
Quoting flyby519 (Reply 4): An idea what the "design life goal" for the ERJ 135/140/145 series is?
Again there really is none. Continue to maintain them and take care of them and you can keep flying them. Take poor care of them and you cut the life from them.
"It's not the size of the dog in the fight, but the size of the fight in the dog"
cobra27 From Slovenia, joined exactly 12 years ago today! , 988 posts, RR: 0 Reply 12, posted (2 years 9 months 3 weeks 2 days 1 hour ago) and read 6026 times:
But what about corosion? Aluminium has a limited lifespan, tensile strength gradually reduces, unlike steel?
MQTmxguy From United States of America, joined Nov 2007, 196 posts, RR: 0 Reply 13, posted (2 years 9 months 3 weeks 2 days ago) and read 5966 times:
Quoting flyby519 (Reply 4): An idea what the "design life goal" for the ERJ 135/140/145 series is? There are some older ones getting up over 30k cycles
I recall reading in the EMB-145 AMM part 1 that the airframe is designed for 60,000 cycles.
Well at least we can all take comfort in the fact that NW will never retire their DC-9s
Macsog6 From Singapore, joined Jan 2010, 477 posts, RR: 0 Reply 14, posted (2 years 9 months 3 weeks 1 day 10 hours ago) and read 5621 times:
Quoting JBo (Reply 2): believe the DC-9 will be the only airworthy aircraft after the apocalypse
Sorry, DC-9's will be hauled to the scrap yards in DC-3's and C-130's.....
But more on point, the A380 is likely to first go to the parkling lot not as a result of cycles but as a result of a severe economic downturn making them - and other aircraft - surplus to demand. Now if I could only predict when that would happen.....
Sixty Plus Years of Flying! "I fly because it releases my mind from the tyranny of petty things." - Saint Ex
PlymSpotter From Spain, joined Jun 2004, 11128 posts, RR: 63 Reply 15, posted (2 years 9 months 3 weeks 1 day 9 hours ago) and read 5607 times:
Quoting Macsog6 (Reply 14): But more on point, the A380 is likely to first go to the parkling lot not as a result of cycles but as a result of a severe economic downturn making them - and other aircraft - surplus to demand. Now if I could only predict when that would happen.....
Actually it would be the opposite, unless the planet encounters a massive reduction in population. Anyway, aircraft are stored, not scrapped. We've just come through a severe economic downturn and many of those stored aircraft are being reactivated now - but note there is not a single A388 or 77W in storage. That's not just because they are new, that's because on average they are the most economic aircraft to keep flying compared to 744s and 343s, especially during a recession. In the A380s case, the only conceivable aircraft which is going to replace it is the A389.
etherealsky From United States of America, joined Apr 2010, 327 posts, RR: 0 Reply 16, posted (2 years 9 months 3 weeks 1 day 9 hours ago) and read 5570 times:
Quoting EMBQA (Reply 1): Aircraft do not have a limited life as long as you continue to maintain them
I believe this about unpressurized aircraft, but even pressurized ones? Aren't there critical, irreplaceable components that are eventually done-in by fatigue?
Quoting cobra27 (Reply 12): But what about corosion? Aluminium has a limited lifespan, tensile strength gradually reduces, unlike steel?
Repairs can go a long way (my understanding is that the old Douglas, Lockheed, and McD products - and even Boeing to some extent - were so rugged that all you needed was to metaphorically "throw a patch on" and go fly. Maybe someone who worked on those beasts (DC-8, DC-10, 707, 727, etc.) can confirm that or not
.
This was the sight at KARG a couple months ago; all of those aircraft (and a few more out-of-frame) were in the process of being scrapped. The two ex-CO 737's in the top-right of the photo even had winglets.
Besides, there are always the lucky few that get turned into restaurants or hotels
MEA-707 From Netherlands, joined Nov 1999, 4117 posts, RR: 37 Reply 17, posted (2 years 9 months 3 weeks 1 day 9 hours ago) and read 5543 times:
Quoting etherealsky (Reply 16): This was the sight at KARG a couple months ago; all of those aircraft (and a few more out-of-frame) were in the process of being scrapped.
The point of Plymspotter is that relative new aircraft will just be stored. Like some 744Fs were stored during the heavy cargo downturn last year but are now reactivated though. On your picture there are only aicraft built before about 1992.
While older aircraft, including MD-80s, 737-300/400/500 (the Continentals were old yet had winglets which probably were salvaged and put on other aircraft) some early A-320s, have been withdrawn to be scrapped, this happens more in a downturn but the current economic boom is not strong enough to save all older 1980s generation aircraft as enough new aircraft come on the market.
nobody has ever died from hard work, but why take the risk?
474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9 Reply 18, posted (2 years 9 months 3 weeks 1 day 8 hours ago) and read 5483 times:
Quoting etherealsky (Reply 16): I believe this about unpressurized aircraft, but even pressurized ones? Aren't there critical, irreplaceable components that are eventually done-in by fatigue?
I think you are assuming I said they would be scrapped and all I was saying was that economic conditions would likely cause them to be parked before they would ever be ready to be made into billions of beer cans.
Sixty Plus Years of Flying! "I fly because it releases my mind from the tyranny of petty things." - Saint Ex
PlymSpotter From Spain, joined Jun 2004, 11128 posts, RR: 63 Reply 20, posted (2 years 9 months 3 weeks 22 hours ago) and read 5288 times:
Quoting MEA-707 (Reply 17): The point of Plymspotter is that relative new aircraft will just be stored. Like some 744Fs were stored during the heavy cargo downturn last year but are now reactivated though. On your picture there are only aicraft built before about 1992. While older aircraft, including MD-80s, 737-300/400/500 (the Continentals were old yet had winglets which probably were salvaged and put on other aircraft) some early A-320s, have been withdrawn to be scrapped, this happens more in a downturn but the current economic boom is not strong enough to save all older 1980s generation aircraft as enough new aircraft come on the market.
Just what I was meaning; new fuel efficient aircraft are not going to be scrapped (yet) - unless they have a serious issue.
I think you are assuming I said they would be scrapped and all I was saying was that economic conditions would likely cause them to be parked before they would ever be ready to be made into billions of beer cans.
Yes sorry, I wasn't aiming the bit about scrapping at you, just a general point.
Burkhard From Germany, joined Nov 2006, 4248 posts, RR: 2 Reply 21, posted (2 years 9 months 3 weeks 22 hours ago) and read 5278 times:
Quoting PlymSpotter (Reply 20): Just what I was meaning; new fuel efficient aircraft are not going to be scrapped (yet) - unless they have a serious issue.
In this case they may be more worth as spare parts than as a total, which is mostly the reason for young scrapped ones.
SEPilot From United States of America, joined Dec 2006, 6258 posts, RR: 39 Reply 23, posted (2 years 9 months 3 weeks 15 hours ago) and read 5082 times:
Quoting cobra27 (Reply 12): But what about corosion? Aluminium has a limited lifespan, tensile strength gradually reduces, unlike steel?
Corrosion and fatigue are different issues, and corrosion affects both aluminum and steel. Fatigue, however, is what limits aircraft life. Steel, if stressed below a certain point, does not fatigue but has essentially infinite life. Aluminum does not. However, under low stress aluminum can work harden, which makes it stronger. This was discovered when Douglas got worried after WWII about all of the ex-military C-47's being put into civilian service, many with unknown history. They got one that had had a lot of wartime service and subjected it to the same stress tests as they had the original prototype. They were very much surprised to find that the wing failed at about 50% HIGHER load than the original; they ultimately attributed it to work hardening. Again, this is distinct from fatigue, which will still affect it. The main issue for airliners is fatigue from pressurization/depressurization; non-pressurized aircraft are generally not significantly affected by fatigue, with one notable exception: small aircraft used for pipeline inspections have had their wings fail from fatigue due to continual flying at low level in turbulent conditions. This happened to at least one Piper Cherokee, which resulted in an AD requiring removal and inspection of the wings after 5000 hours; this severely impacted the value of Cherokees while it was in force. After several years of inspections and not finding any problems, it was modified to only apply to aircraft subject to severe service, IIRC.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
iahcsr From United States of America, joined Jun 1999, 3308 posts, RR: 45 Reply 24, posted (2 years 9 months 3 weeks 15 hours ago) and read 5024 times:
Quoting etherealsky (Reply 16): This was the sight at KARG a couple months ago; all of those aircraft (and a few more out-of-frame) were in the process of being scrapped. The two ex-CO 737's in the top-right of the photo even had winglets.
KARG is a scrapping facility, not for long term storage. The climate in Arkansas is much too humid, hence the reason most 'boneyards' are in desert locations.
Working very hard to Fly Right....
25 alwaysontherun: I believe with GA aircraft it is much more simple. No "cycles" as such……… As long as your engine is up to scratch and the airframe is looked aft
27 CanadianNorth: Anyones really, I was just trying to say the 737's life has nothing to do really with the Embraer's, I was just throwing the fact out there. http://a
28 tdscanuck: This depends, almost entirely, on how the structural design was done. Anything that was designed as damage tolerant (which is every large jet in curr
29 474218: When Lockheed designed the L-1011 it was assumed that there was no maximum number of cycles/hours it could be operated as long as it was properly mai
30 soon7x7: The last DC3 revenue flight I was on was at the time, the only commercial aircraft with 146,000 hours on her. She belonged to PBA airlines I'll bet s
32 soon7x7: Now A busers...don't get mad...I'm not trying to start an A/B war but it is a fair question I'm going to ask. I have been seeing a fair amount of A320
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Just what I was meaning; new fuel efficient aircraft are not going to be scrapped (yet) - unless they have a serious issue.
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