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Bruce
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High Mileage Aircraft

Sat Oct 08, 2005 4:38 pm

today I was told that Northwest's latest retirement was ship # 1221, a DC-10, and it has logged about 128,000 hours and about 28,000 cycles. What I'm wondering is, how does that stack up in terms of the llifespan of a DC-10. what is the airframe's design limit? Would a plane with this many hours be considered old enough to trash for parts, or might it still find life with a new operator? There's a big difference between the landings and hours, this probably is an indicator of a plane that was used almost exclusively for long haul flights where you routinely fly 6 - 8 hours with only 1 landing. But 28,000 does not seem too high....or is it?

bruce
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MX757
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RE: High Mileage Aircraft

Sat Oct 08, 2005 5:16 pm

No 28,000 cycles is not that much. My understanding is aircraft cycles is a better gauge of aircraft wear and tear than aircraft time in the air. Most airliners including the DC-10 don't have a set design limit. As long a the required heavy checks, aging aircraft inspections, AD's, and modifications are complied with the aircraft could technically fly forever. What usually does an aircraft in is corrosion, fuel efficiency, 3 man cockpit verses 2, and the amount of maintenance required to keep the aircraft airworthy. An aircraft is like a car in this aspect, the older it gets the more maintenance it requires. Parts wear out a lot more, you get a lot more wiring problems, overnight maintenance starts becoming a real headache. I can go on and on but now I'm starting to get a headache!  headache 

BTW: 128,000 hours of aircraft time equals almost 15 years in the air.
Is it broke...? Yeah I'll fix it.
 
Aviation
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RE: High Mileage Aircraft

Sat Oct 08, 2005 5:42 pm

is it not true tho that 128000 hours is a good lifespan I do not know about cycles but I believe that 128,000 hours is very good andthing over 100,000 isnt it?

I rember hearing somewhere that the DC-8 jet trader is a very good a/c because it was one of few to make it past 100,000 hours does this sound correct?

Thanks,
Aaron J Nicoli
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MX757
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RE: High Mileage Aircraft

Sat Oct 08, 2005 6:03 pm

Yes, high time does show the aircraft's durability. Douglas always did build durable airplanes. Ref: DC-3, DC-4, DC-6, DC-8, DC-9, and DC-10. But high time does also show wear and tear.

Keep in mind that an aircraft is a commodity just like any other goods. If another operator wants it for say a freighter, then it will be converted. But if it is deemed by the owner that they can make more money by parting the aircraft out then that will happen. Unfortunately I feel this going to happen to ship 1221. After it's stripped of everything valuable it will be chopped up and turned into beer cans.  brokenheart 
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Buzz
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RE: High Mileage Aircraft

Sun Oct 09, 2005 8:24 pm

Hi Bruce, and MX757: Buzz here. My favorite high time aircraft is a 1937 DC-3, N136PB // NC18121. She had 91,400 hours on her (and i don't know how many cycles) when we woke her up and ferried her near Portland Oregon. You can see a photo of her in the AOPA magazine, Sept. 2005 on an article about Pearson Airfield. She's up for sale...
128,000 hours... that's a bunch. At work the airliners seem to fly about 3000 hours a year. Cycles vary according to the fleet (short range = more landings).
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RE: High Mileage Aircraft

Mon Oct 10, 2005 1:58 am

Quoting Bruce (Thread starter):
But 28,000 does not seem too high....or is it?

28,000 cycles is very low, but 28,000 cycles and 128,000 hours to me doesn't match up. To me, it should be around 40,000 cycles with that kind of time. Hours are also not the benchmark for an aircraft, cycles are. Look at most any Inspection.. it's based of cycles.
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Jetlagged
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RE: High Mileage Aircraft

Mon Oct 10, 2005 2:09 am

Transatlantic flights from MSP and DTW are around 8 to 10 hours long, so 28,000 cycles in 128,000 hours is quite feasible. That's an average of 4.57 hours per flight.
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prebennorholm
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RE: High Mileage Aircraft

Wed Oct 12, 2005 7:34 am

128k hrs, with today's fuel prices that spells a total fuel burn worth something like $600-700 million.

So if you can buy a new (or newer) and somewhat more fuel efficient bird at, say, $150 million, then it is relevant to say that this probably 30+ years old DC-10 has had its time.
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KevinL1011
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RE: High Mileage Aircraft

Wed Oct 12, 2005 11:28 am

Check the hours/cycles on that Hawiian Air 737 that peeled open. Luckily the seat tracks were newer!
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RE: High Mileage Aircraft

Wed Oct 12, 2005 11:48 am

Just wondering when was ship# 1221 retired?

Its a good bunch of hrs on that bird.

A second question, and please my intentions is not to start a new NW dc9 discussion, but to get a short answer.

When I flew NW back in March 2001, I remember reading in their inflight magazine that their Dc-9 was supposed to be retired when an airframe reached 100.000 cycles. How many hrs is such a dc-9 likely to have accumulated during its life. my guess is around 80-100.000 hrs.

Tg 747-300
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HAWK21M
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RE: High Mileage Aircraft

Wed Oct 12, 2005 4:27 pm

Quoting Kevinl1011 (Reply 8):
Check the hours/cycles on that Hawiian Air 737 that peeled open

Which one was that.Any Details.
regds
MEL
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Tg 747-300
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RE: High Mileage Aircraft

Thu Oct 13, 2005 4:07 am

The Aloha 732 that was involved in the incident/accident at Maui April 28 1988 was N73711 (Msn / C/n: 20209/152)

Year built: 1969
Total airframe hrs: 35496 hours
Cycles: 89680 cycles

As far as i know this, together with a few other 732 in Alohas fleet, was low hr high cycle ex WN birds.


info regarding cycles/hrs is from www.aviation-safety.net

tg 747-300
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greasespot
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RE: High Mileage Aircraft

Thu Oct 13, 2005 10:16 am

Everyone trots out aloha as the benchmark. While it was part of the problem with boing is they use a laminated skin for the fuslage. THey started to disbond at the edges and allowed corrosion into the pannels which weakened it. NOw douglas on the 9's used a solid skin that is not subject to the same disbonding and there for in a sende wil last longer.....in theory....

That is why the boings look like they have been in a car accident with all the repairs and mods on the Lap joints to comply with ageing aircraft AD's... There used to be ugly boiuler plate type repairs scabbed on...Now the lated mod is a nuch cleaner repair but if you are besie the aircraft you can see the repaier over the windowbelts.....The douglas produts do not have the same repair...


Is this relevant to the thread i dunno but it is interesting piece of trivia..
GS
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JHSfan
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RE: High Mileage Aircraft

Sat Oct 15, 2005 7:59 am

Replying a bit late - I have looked at 5 DC-10's that are listed on GlobalPlaneSearch.com (GPS).
For each I have listed Serial #, Year of manufacturing, Total time in air (in hours), Total # of cycles and my source (the source of "GPS").
I would say that a DC-10 with 128,000 hours and 28,000 cycles has flown quite a lot.
For a short haul plane (many cycles - few hours) it's not that much.

MSN: 46554
Year: 1973
TT (Hrs): 85949
TC: 20509
Source: planemart

MSN: 46981
Year: 1978
TT (Hrs): 80587
TC: 16345
Source: Speednews

MSN: 46999
Year: 1979
TT (Hrs): 67335
TC: 15951
Source: planemart

MSN: 47812
Year: 1979
TT (Hrs): 70108
TC: 14742
Source: Speednews

MSN: 48275
Year: 1981
TT (Hrs): 42194
TC: 16191
Source: Speednews


Yours in realtime
JHSfan
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Lemurs
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RE: High Mileage Aircraft

Sun Oct 16, 2005 6:51 am

Quoting Greasespot (Reply 12):
That is why the boings look like they have been in a car accident with all the repairs and mods on the Lap joints to comply with ageing aircraft AD's... There used to be ugly boiuler plate type repairs scabbed on...Now the lated mod is a nuch cleaner repair but if you are besie the aircraft you can see the repaier over the windowbelts.....The douglas produts do not have the same repair...

I'm not sure what you mean there exactly. I've been on a fair number of NW's DC-9's recently, and most of them look like they've been in a number of bar brawls...riveted patches here there and everywhere.
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greasespot
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RE: High Mileage Aircraft

Sun Oct 16, 2005 9:48 am

Yeah but those patches are from ramp rash or other forms of corrosion.....All older B737-200 have had their entire lap splice joints ( place where the top skin meets the window skin) completely cut out and replaced. I am going by memory but I think this modification has to be accomplished by 60 000 cycles due to an AD. It is a "ceaner" repair than what used to be done in the past. Before they put a big over size rivet and a scab patch on the joint. On the douglas product because they are not a laminated skin( layers of alum. essentially glued together to form skin) they do not have this problem. See when the bond of the glue weakens it alows ingress of moisture and starts up corrosion between the laminated skins.

Now all planes will get corrosion in different places. usually low areas like bellies. B-737's can get it in the roof due to the manfacture process.

I do not know if the 717 uses a lamiated skin or not. Probabbly laminated as it is cheaper.( according to boeing rep.)

I know this is kind of hard to visualize with out seeing the repair process.

I found a link that will sow a lap joint mod.
http://www.b737.org.uk/fuselage.htm


GS

[Edited 2005-10-16 02:49:37]
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
 
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HAWK21M
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RE: High Mileage Aircraft

Sun Oct 16, 2005 4:57 pm

Quoting Kevinl1011 (Reply 8):
Check the hours/cycles on that Hawiian Air 737 that peeled open



Quoting Tg 747-300 (Reply 11):
The Aloha 732 that was involved in the incident/accident at Maui April 28 1988 was N73711 (Msn / C/n: 20209/152)

I've heard of the Aloha Incident.Whats the Hawiian Air one.
regds
MEL
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KevinL1011
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RE: High Mileage Aircraft

Sun Oct 16, 2005 5:17 pm

Quoting HAWK21M (Reply 16):
I've heard of the Aloha Incident.Whats the Hawiian Air one.
regds
MEL

Sorry Mel....my bad! It was Aloha. I mistakenly said Hawiian. (well heck, that's where it happened).
Gday!
Kevin
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Tg 747-300
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RE: High Mileage Aircraft

Wed Oct 19, 2005 11:40 am

Quoting Greasespot (Reply 15):
All older B737-200 have had their entire lap splice joints ( place where the top skin meets the window skin) completely cut out and replaced. I am going by memory but I think this modification has to be accomplished by 60 000 cycles due to an AD.

I don't know if im looking up the right thing, but i know that FAR 91.410 " Special Maintenance Program Requirements" limits the 737- all models to 60.000 cycles, unless you do some special inspections/alterations to the fuselage pressure boundary.

btw: the Dc-9, MD80 have the same 60K cycle limit.

Don't know if thats what you were thinking about but,

tg 747-300
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Lemurs
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RE: High Mileage Aircraft

Wed Oct 19, 2005 3:00 pm

Quoting Greasespot (Reply 15):
Yeah but those patches are from ramp rash or other forms of corrosion.....All older B737-200 have had their entire lap splice joints ( place where the top skin meets the window skin) completely cut out and replaced

Ahh yes, I see what you mean now. I had even read that piece on b737.org.uk before, I just didn't recognize that this was the same thing you were referring to. Those are some ugly repairs.
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brons2
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RE: High Mileage Aircraft

Wed Oct 19, 2005 3:11 pm

Quoting Tg 747-300 (Reply 18):

btw: the Dc-9, MD80 have the same 60K cycle limit.

AFAIK the DC-9/MD-80 has a 100,000 cycle airframe limit, not 60K.
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greasespot
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RE: High Mileage Aircraft

Wed Oct 19, 2005 8:01 pm

Yes that picture in the link is the special Mod that is required to keep going past 60,000 cycles.

There are some newer MODS and are much prettier (they use countersunk rivets and flush patches instead of the boilerplate and round headed rivets.)

But when you walk next to the airplane there is not doubt it is there.

I cannnot speak for the DC-9's except in generalities, as I have never worked on them before. I do not know if the same ageing aircraft mod applies to them but i do not think not as I have been arround AC's -9's when they were still in service and did not see the same mods done.

GS
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Lemmy
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RE: High Mileage Aircraft

Thu Oct 20, 2005 1:47 am

The website says that the 737-200 lap joint mod takes 15,000 man hours. That's a lot of hours, right? How does that measure up to a C or D check?

More importantly, how economical is it to spend 15,000 man hours repairing a plane that's already 50k cycles into its 60k cycle life? Have lots of airlines done this mod?
I am a patient boy ...
 
Okie
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RE: High Mileage Aircraft

Thu Oct 20, 2005 2:32 am

Quoting Lemmy (Reply 22):
The website says that the 737-200 lap joint mod takes 15,000 man hours. That's a lot of hours, right? How does that measure up to a C or D check

Well at $30.00 per man hour (wages and benefits) that would be $450,000
Just plug in what ever wage rate you wish.
I am sure that for instance removal of the interior is included that you could obviously take advantage of for a "C" or "D" to defer some of the cost.

The appearance after the modification makes the old birds look like an old ship or an old boiler and add a lot of weight I would quess. I have been on a couple of those birds with the repair and it looks worse in person than pictures can produce.


Okie
 
greasespot
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RE: High Mileage Aircraft

Thu Oct 20, 2005 4:34 am

It is usually done in conjunction with a C-check.....And yeah it costs upwards of 500k-1 000 000 USD( contrary to what people think airplanes do not fly on fuel they fly on U.S.D  Smile. And that does not include fixing problems what they find. You rarely open an A/C to that extent and NOT find problems.

It must be worth it since all ours have been done. Remeber that cost will be costed over about 20 000 cycles before the AC is scrapped.

Oh and this mod is required at that cycle for ALL B737 including the NG ones.

GS.
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"

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