When to ground a warbird?

[A2C]

Probably not, I just stick to principles.

[John Dupre]

I think you'll find that many -- most -- warbird owners put self-imposed G limits on their airplanes that are well inside the design limits of the airplane.

They don't have to. If the plane has been restored properly, and is maintained properly it can be flown to the operating limitations. That's a thoroughly documented fact.

Of course no one has to do anything. The point of the thread as I see it is what kind of criteria should be used to determine when an aircraft should be grounded to preserve it as opposed to continuing to fly it. Each owner or organization will have to decide for themselves. People have been posting thier suggestions as to what criteria they think are important. I don't think anyone is trying to establish absolute rules or laws regarding preservation of historical aircraft. If you want to fly the last surviving Belchfire 100 that Biggles used to score his 400th victory go right ahead. Just remember that by the vary nature of flying, flying anything is more dangerous than not flying it. The same is true of running a train or driving a car but being in the third dimension makes flying much more dangerous. That danger is instrinsic to the activity and no amount of restoration is going to mitigate it as no amount of maintenance will mitigate it for current aircraft.

Robert Mikesh of the NASM used to talk to warbird pilots about the dangers of operating thier aircraft and especially about corrosion. Owner after owner would tout how well maintained thier aircraft were and he could always go to some point on the plane and find corrosion. Not necessarily dangerous levels but corrosion nonetheless. It was inevitable in any aircraft not kept in a climate controlled environment. Sure you treat it but everytime the aircraft is stripped and treated it loses some of its original condition.

The fact remains that if you want to know what a wartime aircraft really looked like, just how exactly it was wired, plumbed and outfitted for war, with a few exceptions, you need to go to a static example in a museum. No flying example is exactly like its brothers were during the war, usually because there has to be some kind of modern radio installed.

As for the attitude "they were built to run so I run 'em". No one and I mean no one really knows what can happen to a 65 year old engine in terms of fatigue cycles versus age. I know of warbird pilots who ALWAYS make a point of hugging and saying I love you to their loved ones before they fly because they cannot know with certainty how the flight will end. Going easy on the engine is just common sense.

[Kyleb]

I think you'll find that many -- most -- warbird owners put self-imposed G limits on their airplanes that are well inside the design limits of the airplane.

They don't have to. If the plane has been restored properly, and is maintained properly it can be flown to the operating limitations. That's a thoroughly documented fact.

There is no technology out there that can tell that an unblemished aluminum spar won't develop a fatigue crack the next time it has a load cycle. As alluded to by another contributor, these airplanes are 60-70 years old and there is no telling how much abuse or how many fatigue cycles they have been exposed to. Unless every component is replaced, effectively returning the aircraft to new condition, these aircraft are increasingly subject to structural failure. The folks who limit their aircraft to less than design loads are cognizant of that and operate their aircraft with that in mind.

Am I saying that the sky is falling and these aircraft should be grounded? Not at all. But I do recognize that materials have their limitations and the fact about aluminum is that it has a limited fatigue life.

Which means that as years go by, flying warbirds will undergo a transformation from original airframes to something equivalent to George Washington's hatchet - the one that has had two new handles and a new head since 'ol George cut down that cherry tree.

[BHawthorne]

I mostly find threads like this to be troll food. There is no "right answer". It's like religious and political threads. You'll get all sorts of answers from every extreme and even a few people that will decide they can't argue a point without getting personal. Just let the owner do what he wants and go on with life. Established regulations dictate the rest.

[A2C]

Kyleb wrote:

Unless every component is replaced, effectively returning the aircraft to new condition, these aircraft are increasingly subject to structural failure. The folks who limit their aircraft to less than design loads are cognizant of that and operate their aircraft with that in mind.

Am I saying that the sky is falling and these aircraft should be grounded? Not at all. But I do recognize that materials have their limitations and the fact about aluminum is that it has a limited fatigue life.

Note: These are somewhat dangerous and irresponsible statements, and must be taken into account and or challenged:

Can you tell everybody what your credentials are, and by what reference or authority you have made the above statements? There is nothing written in the AC-4313 on an airworthy aircraft stating what you have written, and if what you are saying is true, you are claiming the following:

Aircraft are being fraudulently declared "airworthy" and are being flown illegally in (not airworthy) condition. This is a serious claim. Explain yourself. Please also list names and N numbers.

You are also indicating that A&P and IA mechanics themselves are commiting forgery and fraud in signing off "airworthy", non-airworthy airframes. Please explain.

[262]

after 60+years people do not know the war of a ww2 fighter type plane.
people spend 1,000,000 on a plane and lots of money on maintenance,to fly racetrack patterns at airshows.3 to 4g loops and rolls and low fly buys.if you can build a replica for less money and push the plane harder,put on a organize airshow graba## dog fight you will get the kids to pay a lot more attention.they will show a lot more respect and want to be part of a real vet plane.now the kids are F-16,F-18,AH-64,UH-60,new war vets.this is why we need to think a head and teach our kids not to repeat the past.replica project also give a lot of jobs bill

[A2C]

if you can build a replica for less money and push the plane harder,put on a organize airshow graba## dog fight you will get the kids to pay a lot more attention.they will show a lot more respect and want to be part of a real vet plane.now the kids are F-16,F-18,AH-64,UH-60,new war vets.this is why we need to think a head and teach our kids not to repeat the past.replica project also give a lot of jobs bill

Be specific, you're speaking in generalities. A warbird can be flown to several g's just like most anything built today. Again another moot point.

[A2C]

if you can build a replica for less money and push the plane harder,put on a organize airshow graba## dog fight you will get the kids to pay a lot more attention.they will show a lot more respect and want to be part of a real vet plane.now the kids are F-16,F-18,AH-64,UH-60,new war vets.this is why we need to think a head and teach our kids not to repeat the past.replica project also give a lot of jobs bill

Be specific, you're speaking in generalities. A warbird can be flown to several g's just like most anything built today. Again another moot point.

[Randy Haskin]

Note: These are somewhat dangerous and irresponsible statements, and must be taken into account and or challenged:

Can you tell everybody what your credentials are, and by what reference or authority you have made the above statements? There is nothing written in the AC-4313 on an airworthy aircraft stating what you have written, and if what you are saying is true, you are claiming the following:

Aircraft are being fraudulently declared "airworthy" and are being flown illegally in (not airworthy) condition. This is a serious claim. Explain yourself. Please also list names and N numbers.

You are also indicating that A&P and IA mechanics themselves are commiting forgery and fraud in signing off "airworthy", non-airworthy airframes. Please explain.

Before you get all hot and bothered, take a read at what WIXer Tim Savage found when his company started completely disassembling T-6s and SNJs to rebuild them:

http://www.courtesyaircraft.com/Midwest ... %20PDF.pdf

You seem to think that these statements indicate some kind of knowing and willful signoff of unairworthy parts as airworthy.

What people are REALLY saying is, "you don't know what you don't know". In the case of the T-6s, they found heavy corrosion in areas that aren't usually -- or ever -- looked at.

What I said in a previous post was that as a pilot, you never know what a previous pilot has done to the airplane. As much as warbird pilots have demonstrated a lack of understanding of "asymmetric G", it's reasonable to expect that stress damage has unknowingly been done on many warbird trainers and fighters. Again, nothing seedy or intentional or illegal - pilots simply don't KNOW that they are hurting the airplane.

Third, metal has a finite number of cycles -- and on warbirds, there is a reasonable chance that because of the conditions these airplanes were built under in the 1940s, it's not possible to apply current/modern standards of determining that fatigue life. In the heavy rebuilds of Mustangs and T-6s in the last decade, it has become obvious that standards for forging and extruding metal during WWII were lowered; one, for expediency, and two, because these airplanes simply weren't expected to be around long enough for it to matter.

So, all of these reasons put together are why many warbird owners and operators take it easy on their airplanes. Because it's better to be easy on your machine and be alive than it is to fly it out to some limit printed in the operating instruction and be dead wrong.

Last edited by Randy Haskin on Tue Mar 24, 2009 12:42 am, edited 1 time in total.

[262]

again, it is the history we will lose,please go ask a plane owner to push his plane to combat power or g limit and see what he said.bill

[A2C]

He's wrong.

What people are REALLY saying is, "you don't know what you don't know". In the case of the T-6s, they found heavy corrosion in areas that aren't usually -- or ever -- looked at.

Conversely, you know what you know. In saying they "aren't usually looked at", he could be refering to people doing illegal paper sign-offs. (Certainly no one I know). You can't make sweeping generalities.

What I said in a previous post was that as a pilot, you never know what a previous pilot has done to the airplane. As much as warbird pilots have demonstrated a lack of understanding of "asymmetric G", it's reasonable to expect that stress damage has been unknowingly been done on many warbird trainers and fighters. Again, nothing seedy or intentional or illegal - pilots simply don't KNOW that they are hurting the airplane.

B.S. That can apply to any airplane.

Third, metal has a finite number of cycles -- and on warbirds, there is a reasonable chance that because of the conditions these airplanes were built under in the 1940s, it's not possible to apply current/modern standards of determining that fatigue life. In the heavy rebuilds of Mustangs and T-6s in the last decade, it has become obvious that standards for forging and extruding metal during WWII were lowered; one, for expediency, and two, because these airplanes simply weren't expected to be around long enough for it to matter.

Wrong. Why have B-52's been flying for 10's of thousands of hours and over 50 years w/o cracking? Fatigue cracking occurs in predictible and traceable and specific areas on the aircraft.

So, all of these reasons put together are why many warbird owners and operators take it easy on their airplanes. Because it's better to be easy on your machine and be alive than it is to fly it out to some limit printed in the operating instruction and be dead wrong.

Non-sense. An airplane can be flown to it's operating limits. If patterns of cracking or anything else emerge over the lifetime of the aircraft it can be taken care of w/ AD's.

[262]

ad,s are in place to fix a known problem after a plane has killed a pilot!bill

[A2C]

ad,s are in place to fix a known problem after a plane has killed a pilot!bill

So what are you trying to accomplish in saying this? Are you saying you can't accept any risk in life? That's why we have lawyers, because no one accepts risk and responsibility. They want to create a utopia. There are no utopias. Bill, you can have a heart attack driving home tomorrow. (I hope you don't).

So with aircraft. If you want to fly anything at all you take a risk and live with it. If you worry yourself to death over an AD that is impossible to predict, maybe you should find another hobby or profession.

[Randy Haskin]

Not sure why I feel compelled to even answer this, save for the fact that I think your line of thought is just completely off the tracks.

Conversely, you know what you know. In saying they "aren't usually looked at", he could be refering to people doing illegal paper sign-offs. (Certainly no one I know). You can't make sweeping generalities.

I'm making sweeping generalities? Hmmm. The article I attached was talking about de-riveting horizontal stabilizers and wing center sections. When was the last time an annual had that required as one of it's checks? I'm not saying that there aren't maintainers out there who pencil-whip maintenance, but that wasn't the point of my post or anybody else's post here -- YOU brought that up.

B.S. That can apply to any airplane.

You're right -- that can be applied to any airplane. But that makes the statement FAR from being BS...it makes it even MORE applicable to warbird aircraft.

Wrong. Why have B-52's been flying for 10's of thousands of hours and over 50 years w/o cracking? Fatigue cracking occurs in predictible and traceable and specific areas on the aircraft.

Interesting that you say categorically, "WRONG", and then go on to mention something completely un-related to warbirds. Unless, of course, you know about some B-52s that were made during WWII and are still operating that I am not aware of. Last time I checked the currently-flying B-52Hs were made in the 1960s.

I'm talking about airplanes made during WWII -- between, say, 1943 and 1945. A time when raw materials were not readily available. A time that, it's believed, precision in metallurgy was foregone because of the need to crank out airplanes. A time that corrosion control on interior surfaces was foregone because the manufacturer didn't think the airplanes would exist long enough for corrosion in those places to be an issue.

So, I'll entertain it when you say "wrong" so long as you can back it up with an educated discussion about metallurgy and corrosion control at US aircraft manufacturers in the mid 1940s.

Non-sense. An airplane can be flown to it's operating limits. If patterns of cracking or anything else emerge over the lifetime of the aircraft it can be taken care of w/ AD's.

This is probably one of the most ignorant and misguided statements I've read on WIX in a long time.

You are right -- in theory. So long as an airplane was built correctly, maintained correctly, and flown correctly. Those are things you just can't be sure of on many warbird aircraft.

Just how much time to do you have flying warbirds?

Last edited by Randy Haskin on Tue Mar 24, 2009 1:35 am, edited 1 time in total.

[262]

a2c,
you are way in left field,have you been "danger close" with a a-10 or spector inbound?you dont have a clue!that is why we need to give our kids a clue.i have 2 kids in iraq and1 going in june.i have a clue.bill