There's such thing as too many Airframe hours right?

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Hector Parra

Pre-takeoff checklist
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Hector Parra
..from a philosophical perspective, if everything is maintained, inspected, and updated/repaired then at what point is the original plane no longer the original? If you've had a family heirloom axe for centuries but every few decades it gets a new handle and head is it really the same axe?

For what it's worth I've heard of schools taking trainers to 30K hours. And as another data point Cirrus has (had?) an airframe life, as did Tigers, for the wings, of around 12K hours.. which can be extended incrementally with inspections

I wouldn't be too worried about it if it's been maintained and passes pre-buy muster. Even if you fly your plane 300 hrs a year (don't most fly closer to 60-120?) it will take you a long time to add any meaningful age to a plane once it's racked up a few thousand
 
Tantalum said:
..from a philosophical perspective, if everything is maintained, inspected, and updated/repaired then at what point is the original plane no longer the original? If you've had a family heirloom axe for centuries but every few decades it gets a new handle and head is it really the same axe?

For what it's worth I've heard of schools taking trainers to 30K hours. And as another data point Cirrus has (had?) an airframe life, as did Tigers, for the wings, of around 12K hours.. which can be extended incrementally with inspections

I wouldn't be too worried about it if it's been maintained and passes pre-buy muster. Even if you fly your plane 300 hrs a year (don't most fly closer to 60-120?) it will take you a long time to add any meaningful age to a plane once it's racked up a few thousand
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Thanks for the advice. Got curious as is the first one that I saw listed with such high airframe hours.
 
I have flown some Cessna 206 and 207 that well surpassed 30,000 hours. These planes worked in Alaska were not babied. One 206 had sat for two years on its back up on the north slope of Alaska, and I still flew it.
 
Hector Parra said:
how much more do you think this airframe can hold?
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FYI: from a maintenance perspective, its not the total hours flown but how it was maintained that counts which includes any damage history. Have seen 3000TT airframes that were on the verge of failing. Plus there are some models out there that a lack of damage history/major repair would be suspect. High total time has never been a deal breaker in my book.
 
If I had pick an airframe to fly with 15k hours, the strut-braced cessnas would be high on the list.

I mean, if it's just a time builder as opposed to something you plan to keep forever, a cheap high-time plane like that could be perfect. I'm not sure that one is cheap enough though.
 
No annual in a year and a half for a $60k 172? No thanks.
 
Jim K said:
If I had pick an airframe to fly with 15k hours, the strut-braced cessnas would be high on the list.

I mean, if it's just a time builder as opposed to something you plan to keep forever, a cheap high-time plane like that could be perfect. I'm not sure that one is cheap enough though.
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Well, we don't have as much options here in Canada as in the States. There's a Globe Swift for $35, a Luscombe 8A for $38, a C150 for $43 and some others below the $50k mark that I've set myself as maximum purchase value. But I'm not on a hurry so I'll wait and see what else comes available.
 
Hi Hector... Also from Canada... Our market up here is crap compared to the U.S. market. You got to be patient. There are good deals every two or three months but once they come up, you have to be fast, put down a deposit, do the pre-buy and get it, otherwise, someone else will take it.

In the past 12 months, I managed to buy two helluva deals. One Cessna 150 and one Piper Cherokee... I flipped the Cessna for a decent profit, after I cleaned her up and put her through an annual inspection and I'm keeping the Cherokee for the next five years or so before upgrading to a Cherokee Six or something similar. When I bought the Cherokee, I put down a deposit within two hours of the guy posting the plane on Kijiji. I was caller number three, but the first one to make the e-transfer for the deposit. By the time I picked the plane up, he had a waiting list of 20 people waiting for the sale to fall through.

There were two other incredible deals I saw in the past 12 months. I reached out to the sellers of both deals within 24 hours of them having posted the planes, and in both cases, the planes were long gone by the time I called them.

Make sure you look in all places, including Kijiji, LeSpac, Controller, Barnstormers, Trade-A-Plane, and also Facebook Marketplace.

Good luck finding your plane :)
 
Hector Parra said:
how much more do you think this airframe can hold?
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A lot more than you can put on it. Just think, you can buy that plane, fly it 350 hrs over the next yr (~1 hr every day) then sell it for the same amount (or more) unless the the used market collapses. The added time is meaningless at this point.
 
At some (unknown) point, you'll be a test-pilot on every flight. Feel lucky today?
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So does that mean at some point expensive maintenance and periodic inspections can be discontinued? If those task no longer ensure integrity of the aircraft, they can be dropped and we just rely on luck, correct?
 
I have rented a 20,000+-hour 1980 warrior many times and used it for some lengthy trips. (But then, with a Warrior nearly any trip is lengthy.) It flew real IMC with me more than once and I never found myself concerned about the airframe integrity.

Would I buy one with that time on the airframe? Probably not.
 
FYI steel has an unlimited fatigue life below certain stress level (about half of maximum strength) but unfortunately not aluminum. I think I would not go over 15,000 hours just because but I would also want to know where and how it was flown. Also a FAA stress expert said older airplanes tended to actually be stronger because they were often overbuilt to compensate for poorer stress analysis.
 
I don't know about this AC specifically but there are sometimes Life Limited Parts that are no longer airworthy in the eyes of the FAA after some milestone is reached. I know for a Grumman Tiger those life limits are listed in the Type Certificate. I'm sure you can download the TC from the FAAs website and go through it. Equipment installed by STC could have life limits to. If I'm seriously looking at buying an AC, I would get a look at the data the FAA has on the plane. They should have a record of all major alterations and repairs and it costs like $10. That is assuming the previous owners and maintainers filed the 337s like they were supposed to.
 
Chrisgoesflying said:
Hi Hector... Also from Canada... Our market up here is crap compared to the U.S. market. You got to be patient. There are good deals every two or three months but once they come up, you have to be fast, put down a deposit, do the pre-buy and get it, otherwise, someone else will take it.

In the past 12 months, I managed to buy two helluva deals. One Cessna 150 and one Piper Cherokee... I flipped the Cessna for a decent profit, after I cleaned her up and put her through an annual inspection and I'm keeping the Cherokee for the next five years or so before upgrading to a Cherokee Six or something similar. When I bought the Cherokee, I put down a deposit within two hours of the guy posting the plane on Kijiji. I was caller number three, but the first one to make the e-transfer for the deposit. By the time I picked the plane up, he had a waiting list of 20 people waiting for the sale to fall through.

There were two other incredible deals I saw in the past 12 months. I reached out to the sellers of both deals within 24 hours of them having posted the planes, and in both cases, the planes were long gone by the time I called them.

Make sure you look in all places, including Kijiji, LeSpac, Controller, Barnstormers, Trade-A-Plane, and also Facebook Marketplace.

Good luck finding your plane :)
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Hi Chris. Thanks for the feedback. I've been searching on those sites, except for FB. I'll give it a look. Who do you use for your pre-buy inspections? I'm in Montreal and there's also not many planes available for sale in Québec. Most of them seem to be in Ontario and Alberta.
 
I have flown a bunch of a/c that had TT in the 30K range. One 38K. A couple had been ditched in salt water and repaired. One of these had an autopilot that always seemed haunted. Only one military a/c had to be scrapped.
 
Snowmass said:
FYI steel has an unlimited fatigue life below certain stress level (about half of maximum strength) but unfortunately not aluminum.
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That would be my chief concern, long term fatigue that goes undetected. But where and when is that? Obviously there is a lot more to that equation than simple hour total. Despite having a GA fleet with an average age probably approaching 30-40 years old, we still aren't seeing a rash of wings falling off. Bigger question is as the fleet continues to age, will we?
 
My 180 has just under 7000 hours. I am not too concerned about structural integrity, I believe there have only been a couple of mid air breakups of Cessna 180's. One I read about was never solved, but there was a suggestion that large/ fast military aircraft were in the immediate area just before it broke up. The other I heard about was probably an overspeed situation.

These old airplanes were built well, and most of them have been well taken care of. Think about how we use them, occasionally I do 60 degree level banks, that is about the highest g-load it sees, but very far from the design load limits. I very rarely do zero g, and have never done negative g's. I have never done full deflection of a control in flight, but theoretically the plane can handle it at about 120mph. Never exceed speed is 204, fastest I have ever had it is about 165. My uses stress the plane very little in comparison to its design limits.
 
Normal cat is 3.8 g’s - what is the designed safety margin above that?
 
Mxfarm said:
Normal cat is 3.8 g’s - what is the designed safety margin above that?
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1.5 times that. It's to allow for small errors in assembly and material defects.

It's not because the stress analyses were poor.

FAR 23:

§ 23.2230 Limit and ultimate loads.
The applicant must determine -

(a) The limit loads, which are equal to the structural design loads unless otherwise specified elsewhere in this part; and

(b) The ultimate loads, which are equal to the limit loads multiplied by a 1.5 factor of safety unless otherwise specified elsewhere in this part.

Aluminum fatigues easier than steel, but fatigue normally happens when you bend something. You don't want to bend anything. Corrosion is a far bigger factor with aluminum, and cheap annuals let it happen and continue to happen until some poor dude buys the airplane and it's found at the first annual.

Any airplane built in large numbers, like the 172, has known weaknesses and a savvy mechanic knows where to look and what to keep an eye on. Cessna regularly issues Service Bulletins to alert owners and maintainers of deficiencies that have started to appear. The Service Difficulty Databases are also a handy reference. Proper maintenance can avoid most problems. And proper maintenance depends on following the manufacturer's maintenance manuals. There are many ways to do something wrong, and very few ways--sometimes only one way--to do it right.
 
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I have a friend with an F33 Bonanza that has over 27,000 hours on it. It was used as part of the training fleet for Lufthansa. They took excellent care of that airplane. Many of the components were changed out based on a schedule and not condition. I've flown it. It's solid. You wouldn't be able to guess the hours on the airframe if he didn't tell you. When he sells it, it's going to sell for less than an F33 with 4000 hours, but the new owner will end up with a very capable and safe airplane.

Treat airframe hours as an indicator of a need to look a little deeper into the past maintenance history and make sure a good pre-buy inspection is done before buying it. You should get high hour aircraft at a discount versus the market, but also expect to sell it for a bit less one day. In a super hot market (now), the difference in price will be less than in a weak market.

Here's some info on aircraft with over 100,000 hours...
https://simpleflying.com/highest-hours-flight-cycles/
 
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Cirrus has a 12,000 hour limit on the airframe. I doubt if any have made it to that limit yet , since the oldest are were made in 1999. If one is flown 200hrs/yr, that would be 60 years.
 
NoHeat said:
Cirrus has a 12,000 hour limit on the airframe. I doubt if any have made it to that limit yet , since the oldest are were made in 1999. If one is flown 200hrs/yr, that would be 60 years.
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There could be some trainers out there getting 1,000 hours a year. When our State Patrol was actively flying a lot more, they were getting 1,000 hours a year, getting to TBO every other year.
 
Hector Parra said:
Hi Chris. Thanks for the feedback. I've been searching on those sites, except for FB. I'll give it a look. Who do you use for your pre-buy inspections? I'm in Montreal and there's also not many planes available for sale in Québec. Most of them seem to be in Ontario and Alberta.
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I'm far from Montreal, I'm out in the Prairies so my mechanic recommendations probably won't do you any good. Canada is such a small country (people wise, not land size lol) that it's rare finding something locally. I bought two planes locally, at my home airport but I wasn't looking for anything specific - just something with wings that could fly. Once I was looking for something more specific (my Cherokee), I ended up buying it in Ontario, 700 NM away from home, so be prepared to either wait a while or travel to find the plane you want.
 
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