How much TT is too much TT?

FORANE

FORANE

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FORANE
Suppose I were looking to purchase a cherokee 6. Many have been well used, some on part 135. How many hours would you guys say is too many hours on an airframe like the six?

I mention the six as it is not the typical Cessna 1XX trainer which may have seen repetitive hard landings over its years.
 
Depends on how the plane was maintained. I sold the Aztec at 10,000 hours on the airframe. It was a bit tired, but had a hard life beforehand. The 310 has 8,000 hours on it and is in very nice condition.

I don't worry about airframe hours, I want to look at the overall condition.
 
time in and of itself doesn't matter so much, noen of the twin cessna's i flew checks in during college had less than 15K hours on them.

However, you've selected one of the few types that it might matter. If a straight wing PA32 is flown with fuel in the mains and the tips empty, the wings flex and crack at the skin-rib attachment. Count the diamond patches on the wings, figure you'll get minimum one patch per 1000 hours if they have not been burning fuel in the right order. If a PA32 wing already has 4 patches on it I'd pass on the plane and keep looking.
 
Depends, one of our 172s has 16,000hrs of smash n' goes on it and is no more of a maintenance hog (actually less than many) planes of a similar vintage with only a few thousand hours.
 
Over 6,000 or so, I think it's starts cutting into resellability. I'd pause before signing the check on anything with 10,000 or more on it, if for no other reason than I think it'd be a pain in the ass to sell. Airframes may be good to go for 10,000 more hours but as a marginally informed buyer, more hours = more opportunity for someone to !@#$%^ it up. It also tells me that either hired hands or renters were flying it, folks who may not have had as much interest in treating it nicely.
 
Over 5000 hours on the spam cans will peak my attention at annual. loads of stuff start to wear after that.
 
How much is too much depends a lot on the type and what it was used for. I'd pass on a 10,000 TTAF trainer type, but didn't think anything of getting into a DC-3 that had 57,000 hrs on it.


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Skylane81E said:
Depends, one of our 172s has 16,000hrs of smash n' goes on it and is no more of a maintenance hog (actually less than many) planes of a similar vintage with only a few thousand hours.
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That brings up a good point....a plane with a fair amount of hours often has had pretty regular maintenance. There are a lot of high time airplanes that I would feel safer buying than a late 40s/early 50s airplane with less than 2000 TTAF.


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You know, I don't think we actually know yet what kind of issues we could or will see in these airframes. I believe when they built them many years ago, the thought was not that they would still be flying 40years from now. With all that said, we have done a decent job keeping them flying for so long. With not many new airframes coming on-line we will continue to pound the old one. Thousands of hours of use along with corrosion issues-- is going to have an effect on them. TT on the airframe is not going to be a huge deal, but something you need to look at when deciding on a puchase. Just my 2 cents
 
The sweet spot is a plane regularily flown between 50-250 hours per year. Any less, and it's a hangar (tie-down) queen. Any more, than it was probably being used in some sort of commercial operation flown by people wo weren't paying the mx bills. At the end of the day though, it comes down to condition. Hours don't tell the whole story.
 
Brad Z said:
The sweet spot is a plane regularily flown between 50-250 hours per year. Any less, and it's a hangar (tie-down) queen. Any more, than it was probably being used in some sort of commercial operation flown by people wo weren't paying the mx bills. At the end of the day though, it comes down to condition. Hours don't tell the whole story.
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Isn't the regular flying more important for the engine than for the airframe?
 
Bob Noel said:
Isn't the regular flying more important for the engine than for the airframe?
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I have to imagine that regular use is beneficial to all systems. My boat for example sits in the offseason and there's no telling what systems won't be fully functional when I go to use it the first time. Regular use also *should* require regular maintenance, probably the more important part of the equation.
 
guardrail said:
I have to imagine that regular use is beneficial to all systems. My boat for example sits in the offseason and there's no telling what systems won't be fully functional when I go to use it the first time. Regular use also *should* require regular maintenance, probably the more important part of the equation.
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ditto. How does a depth finder stop working from sitting over the winter? yet it happens.
 
I agree with the regular use posts. 200 hours a year is a nice place for a plane. a 50 year old plane with 10,000 hours is a yawn. My first plane was a 10K hour PA28 used almost exclusively as a trainer. It took a lot of time to get the cosmetics up to speed but wings didn't fall off. It was a rock solid plane.

The market does care somehow so pay less when you buy it and expect less when you sell.
 
JHW said:
ditto. How does a depth finder stop working from sitting over the winter? yet it happens.
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Exactly! The winter gnomes killed my bottom machine's LCD, thrilling to find during the first systems check. Also electrical gremlins seem to be prevalant with non-cycled systems.
 
Bob Noel said:
Isn't the regular flying more important for the engine than for the airframe?
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Moving parts should move frequently. We know that's true for engines, but it's also true for airframes, which also have plenty of moving parts.

Cables get stiff and need to be replaced prematurely.

Flight controls get stiff. Anything that needs lubrication needs to move regularily.

An airplane that sits attracts animals. Birds nest, mice chew, squirrels move in, etc.

Problems get noticed faster. Is your plane leaking rainwater? If it's been 6 months since the last time you flew it, you probably won't notice the leak until after corrosion has begun.

Electrical connections corrode. Unless the joint is soldered, vibration prevents corrosion of electrical contacts. Think radio connectors.

As always, YMMV.
 
guardrail said:
I have to imagine that regular use is beneficial to all systems. My boat for example sits in the offseason and there's no telling what systems won't be fully functional when I go to use it the first time. Regular use also *should* require regular maintenance, probably the more important part of the equation.
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I said "more important". I didn't say regular use was of no value for the airframe.
 
There is no hard and fast rule on a high time airframe. It depends entirely on its care feeding and useage....
 
Age harding, work harding, Effect the older aircraft, as does corrosion possibilities.

Cessna used 2024-T3 for most of the structure in the 100 and 200 series aircraft, that is a solution heat treated and age hardened material, the older it gets the more brittle it becomes, add the effects of vibration to work harden the structure, the more brittle it becomes.

This syndrome is best demonstrated by counting the cracks and loose rivets on the older cessnas.

Give me a good airframe under 2000 hours any day over a well maintained 10,000 hour one.
 
What's too much cross-wind component? Depends on the plane and on the pilot. Same with hours on an airframe.

For me, I'd read farther if I saw a 10,000 hour plane for sale at a good price. But if it had 15,000 hours, I'd quit reading.
 
same data tag:

do the hours really matter ?
 

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bbchien said:
There is no hard and fast rule on a high time airframe. It depends entirely on its care feeding and useage....
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Well, there are a few hard and fast rules. Piper has made some planes with mandatory life limited components.

OTOH, the Bonanza(I sound like Geico sometimes) was originally certificated at full gross to the utility category specs. 10,000 hours on a Piper Traumahawk would be the end. 10,000 on a Bo, or pretty much any of the Beech non-trainer class planes isn't a problem.

Sadly, I know nothing about the PA-32 group, just putting my two cents in for my plane... :)
 
How about dye-penetrant studies at stress points of interest, regardless of hours?
 
I'd avoid over 15,000 hrs for a PA-32. Most planes with those times have not led a pampered life. Find something that has lived in a hangar and has been treated well. Condition is everything.
 
Dave Krall CFII said:
How does dye penetrant study cause damage?
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because it leads to the spar doubler being installed for cracks that many experts think are in a non-load carrying structure, and botched installations of the doubler have totalled planes. There has been a tremendous amount of study on this issue and the conclusions are ambiguous. There is evidence that cracks in some doublers are caused by botched ground handling and have nothing to do with flight loads before or after the cracks appear.

You don't want to blindly start doing structural inspections on other airplane types, because it's likely they'll similarly lead to unintended consequences. If there is a problem, fix it, but don't go looking too hard for problems because you'll find some even if they don't exist.
 
JHW said:
because it leads to the spar doubler being installed for cracks that many experts think are in a non-load carrying structure, and botched installations of the doubler have totalled planes. There has been a tremendous amount of study on this issue and the conclusions are ambiguous. There is evidence that cracks in some doublers are caused by botched ground handling and have nothing to do with flight loads before or after the cracks appear.

You don't want to blindly start doing structural inspections on other airplane types, because it's likely they'll similarly lead to unintended consequences. If there is a problem, fix it, but don't go looking too hard for problems because you'll find some even if they don't exist.
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But....but....I thought the FAA was here to help???
 
JHW said:
You don't want to blindly start doing structural inspections on other airplane types, because it's likely they'll similarly lead to unintended consequences. If there is a problem, fix it, but don't go looking too hard for problems because you'll find some even if they don't exist.
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Exactly.
 
I flew plenty of 15,000hr Navajos. But a high time Cherokee Six, if used in the bush - well, think of 400,000mi Toyota pickup. Some Beeches are time limited: Pressurized Barons are done at 10,000hrs.
 
JHW said:
because it leads to the spar doubler being installed for cracks that many experts think are in a non-load carrying structure, and botched installations of the doubler have totalled planes. There has been a tremendous amount of study on this issue and the conclusions are ambiguous. There is evidence that cracks in some doublers are caused by botched ground handling and have nothing to do with flight loads before or after the cracks appear.

You don't want to blindly start doing structural inspections on other airplane types, because it's likely they'll similarly lead to unintended consequences. If there is a problem, fix it, but don't go looking too hard for problems because you'll find some even if they don't exist.
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So would it be accurate to say it is not the inspection process itself at all but, incorrect measures taken upon finding information?
 
Dave Krall CFII said:
So would it be accurate to say it is not the inspection process itself at all but, incorrect measures taken upon finding information?
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No, the inspection is easy. It is the criteria that is (arguably) flawed. You can't mandate an inspection without publishing pass/fail criteria. Since it's done by committee with inadequate data, those criteria are likely to be flawed.
 
Operating FAR 135 cargo, it wasn't uncommon to fly planes with 12,000-15,000 hours on PA-32 and a handful of PA-28's.

Like everything thing else, it all depends. How was the plane treated and are you willing to fix things that have worn out. There is a guy on the red board that replaced a belly skin last year and had to pull his engine to fix corrosion on the firewall this year. His plane has 11,000 hours. The question is what is the cost of fixing verses the cost of a new plane. Figuring that even if you could buy a Turbo Arrow, it would be $500K. The payments on that could buy a bunch of new skins and other airframe parts. Where the problem comes in is that you can't afford a new plane and you can't pay to fix the high time plane too. Now you're in a pickle.
 
Fearless Tower said:
There is a 135 outfit that operates PA28s?
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I flew for Ameriflight in 1988/89 time frame. Yes, I flew an Arrow with 16,000 TT around the southern half of California. We only flew 2 or 3 as most of the single engine piston planes were Lances. Canceled checks were small and somewhat light weight.
 
General aviation airframes are designed to last 20,000 hours.

Commercial airframes are designed to last 100,000 hours.

I would be very concerned about flying an aircraft with more then these hours.

Now this from an engineering stand point and there are several things that can shorten the lifespan, such as corrosion, poorly repaired damage, lack of good maintenance.

I read this in a technical document from 30 years ago. Hopefully my memory is still good.
 
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