Based on the G100UL fuel leak thread what's your position?

[tony]

5 hours ago, Ryan ORL said:

In the referenced FAA Approved Model List (AML), which you did not attach here.

The AML does not ensure compatibility with a specific fuel system. To me this implies every fuel system needs to be testing to ensure compatibility.   I think, I'll write Mr. Nguyen and ask for clarification.

[GeeBee]

I'll say this about those underground tanks at KRHV. They are at least almost as old as I am, because I was loading fuel out of them in 1969 as a line boy.

[EricJ]

31 minutes ago, George Braly said:

What you have written is not consistent with the real world experience and testing.  All of which was supervised and approved by 30 and 40 year experienced turbine and reciprocating propulsion engineers (and specially retained chemist) inside the FAA. 

George

What I have written is consistent with decades-long best practices and guidance in aviation and industrial maintenance.   There were previously posted links to two academic research documents on the topic dealing specifically with o-ring swelling in the context of aviation fuels, as well as FAA guidance and other industrial guidance.   You'll have to forgive me if I'm not persuaded by a single counter-argument from someone with a significant conflict of interest.   I take safety more seriously than that.

 

[Pinecone]

19 hours ago, EricJ said:

That is an appropriate test for determining swell in o-rings, and they appeared to exhibit swell at or above the usual maximum limits for static application, and well beyond limits for dynamic applications.  Depending on how the assessment of swell is made, the swelling may even be well beyond that allowed for static applications.  Those levels of excessive swelling due to exposure to a fuel would indicate that it may be expected to cause issues with nitrile o-rings and hoses in systems exposed to the fuel.   Since one downside of excessive swelling is accelerated degradation and wear of the material, failures may be latent so imho safety concerns are more than justified for both o-rings and hoses.

Again, GAMI tested O-rings installed in aircraft parts.  They have airplanes that have been flying for over 10 years on the fuel.

We have several months of the fuel in the "wild."  

NO issues.  

Yes, that is a valid test, but it also does not predict issues.  More likely, in developing the spec, they tested and got X swelling and said, OK, that is the amount of swelling we tested to, so that is the limit.

Sort of like Cross Wind limits.  Not the actual limit, but the limit of the testing.

[Pinecone]

On 1/6/2025 at 7:45 AM, Z W said:

Some members pretty much ran the EarthX people out of here after they posted about the STC for their new product for the old Mooney fleet. This thread feels the same. We could do better.

The Earth X people took the attitude that they know what we should buy and that is all they would offer.  Sort of like Apple.  Love our product the way WE think it should work.

My stand with them was, I don't need as much weight saving and would feel better with double the capacity.  Their answer was, you don't need that because we say so.  Oh well, scratch one customer.

[Pinecone]

18 hours ago, George Braly said:

 

For follow up on aircraft paint compatibility with G100UL Avgas - - - 

See the following links:

https://g100ul.com/faq#fuel-testing

https://www.youtube.com/watch?v=zrOoq-sB1Ig

I still think you need to test the conditions in the original video.

That is, wet with fuel, allow to mostly evaporate, rewet, repeat.

And with a couple of different primer systems.  Including single part lacquer type primers.

[PT20J]

1 hour ago, Pinecone said:

I still think you need to test the conditions in the original video.

That is, wet with fuel, allow to mostly evaporate, rewet, repeat.

And with a couple of different primer systems.  Including single part lacquer type primers.

I agree. Something happened to the painted parts in the video. The test should be repeated by others with sample parts from various aircraft with different paint systems. The GAMI tests were all with Beechcraft panels. Beech is known for quality. Who knows about the paint systems used by Cessna, Piper, Mooney, etc.

[George Braly]

11 minutes ago, PT20J said:

I agree. Something happened to the painted parts in the video. The test should be repeated by others with sample parts from various aircraft with different paint systems. The GAMI tests were all with Beechcraft panels. Beech is known for quality. Who knows about the paint systems used by Cessna, Piper, Mooney, etc.

Those panels were from aircraft that had been repainted in the field by various different paint shops.   

Further - - we know - - with certainty - -  that  various production runs of 100LL will do exactly the same thing to the paint as is depicted in the Mooney example - -  if the paint quality is poor.  

Can we use that fact as a baseline ?     

                                                                  ************************

Our job was to develop a fuel that could replace 100LL.   Without the lead.   In all of the engines and airplanes.  Without modifications.   At the time, that was the goal of the PAFI project, also.

But that PAFI goal never included creating a replacement for 100LL that did not degrade "inexpensive" paint as 100LL often does, and has for fifty years. 

 

[Marc_B]

3 hours ago, George Braly said:

Further - - we know - - with certainty - -  that  various production runs of 100LL will do exactly the same thing to the paint as is depicted in the Mooney example - -  if the paint quality is poor.  

Can we use that fact as a baseline ?     

Mr. Braly,

With all respect, the conflicting statements (edit) make it very difficult for us to distill fact from fiction.  Earlier you said "Contrary to a lot of internet rumors and gossip -- Neither 100LL nor G100UL Avgas strip aircraft painted surfaces."

The apparent truth is that under certain circumstances G100UL can strip paint, and has been shown to strip paint.

What we'd like to know is what circumstances are we likely to see this happen, and what we can do to prevent it.

It's clear that you have FAA certification for your product.  It's not clear what test data was shared with FAA for certification.  It's clear that you want to selectively share information and engage with GA pilots to help inform them of your product and increase sales of your STC and fuel recipe.  But what's not clear is if your engagement is just advertising or if you're willing to share pointed information to help the GA public navigate this political transition to unleaded fuel safely and without signficant damage to our aircraft or wallet.

Your ICA speaks of using viton and you openly have recommended viton products and say that you recommend "modern" maintenance recommendations (i.e. Bendix advisory you noted), but then say that your test data was done on nitrile components and tested fine.  So if that's the case, why would you suggest changes and why wouldn't you just leave that liability up to the mechanics working on the aircraft??

I'm not sure if the conflicting statements (edited) are intentional, suggest a possible risk that you feel is low, or just lawyer speak, but it is very confusing to well-intentioned pilots who are just trying to make the best decision for themselves and their families.

 

From your earlier post:

[Marc_B]

I think that it seems that the G100UL test with the 100LL sample that had "high toluene" may have been intended to show that 100LL with high toluene caused paint damage whereas the G100UL sample showed didn't??  I was very curious why GAMI wouldn't just test 100LL vs G100UL...why not just a simple "pumped fuel" vs "pumped fuel"??  Why add more toluene to one of the fuels, especially when the amount and concentration wasn't labeled?

https://www.youtube.com/watch?v=zrOoq-sB1Ig

[George Braly]

4 minutes ago, Marc_B said:

Mr. Braly,

With all respect, the double speak makes it very difficult for us to distill fact from fiction.  Earlier you said "Contrary to a lot of internet rumors and gossip -- Neither 100LL nor G100UL Avgas strip aircraft painted surfaces."

The truth is that under certain circumstances G100UL can strip paint, and has been shown to strip paint.

What we'd like to know is what circumstances are we likely to see this happen, and what we can do to prevent it.

It's clear that you have FAA certification for your product.  It's not clear what test data was shared with FAA for certification.  It's clear that you want to selectively share information and engage with GA pilots to help inform them of your product and increase sales of your STC and fuel recipe.  But what's not clear is if your engagement is just advertising or if you're willing to share pointed information to help the GA public navigate this political transition to unleaded fuel safely and without signficant damage to our aircraft or wallet.

Your ICA speaks of using viton and you openly have recommended viton products and say that you recommend "modern" maintenance recommendations (i.e. Bendix advisory you noted), but then say that your test data was done on nitrile components and tested fine.  So if that's the case, why would you suggest changes and why wouldn't you just leave that liability up to the mechanics working on the aircraft??

I'm not sure if your double speak is intentional, insinuating of a known risk that you feel is low, or just lawyer speak, but it is very confusing to well-intentioned pilots who are just trying to make the best decision for themselves and their families.

 

From your earlier post:

 

Mark,

You are right.  I have said that.  I, personally,  have never seen G100UL strip aircraft paint which had been applied in a manner consistent with standard aircraft paint shop practices.     That was the basis and context for my statement.  

I am not, in any way, trying to engage in what you call "double speak." 

I have seen our local FBO 100LL damage (leave a bare spot of aluminum)  when it was dripped (for several days) onto a surface on an aircraft that was not painted with standard aircraft quality paint.   

I note that there would have been "better ways" to address the subject than accusing me of "double speak". 

If the good folks in this "MooneySpace"  continue to attack my personal integrity - -  then I will withdraw from further participation. 

Regards, 

George 

[Marc_B]

36 minutes ago, George Braly said:

If the good folks in this "MooneySpace"  continue to attack my personal integrity - -  then I will withdraw from further participation. 

Mr. Braly,

If asking for clarifications on things that have been commented and answered in conflicting ways is attacking personal integrity, I apologize.  (Perhaps I should have used "conflicting statements" in place of "double speak.")  You speak on behalf of GAMI and for G100UL.  You are the gateway for information regarding a new fuel that has lots of questions.  If you misspeak or answer incorrectly, it matters.  We appreciate your input and appreciate transparency and clarity.

Thanks,

Marc.

[redbaron1982]

Someone already mentioned this: it's a waste of time to keep replying here. There are two different points of views, and none of the positions will change their opinion. All that had to be said was said.

I'm not saying that continuing the "fight" for each part's different interests doesn't make sense. I'm just saying that maybe it would be better to call your house rep and ask them not to ban 100LL, talk with fellow pilots to make them aware of your experience or make more / better tests to convince customers that your fuel is safe.

[DonMuncy]

1 hour ago, George Braly said:

If the good folks in this "MooneySpace"  continue to attack my personal integrity - -  then I will withdraw from further participation. 

Regards, 

George 

George,

I am certain it is very clear to you that there are many folks on this forum who fully support you and your products.

It is equally clear that there are many who are respectfully cautious about G100UL.

And there are some who are downright nasty, and question your integrity and motives.

I suspect that this diversity among members/posters is probably typical of most forums.

I would sincerely hope that you do not let the few who attack you, taint your view of the majority of us, and you will continue to participate in the exchange of ideas and information.

[Pinecone]

3 hours ago, PT20J said:

I agree. Something happened to the painted parts in the video. The test should be repeated by others with sample parts from various aircraft with different paint systems. The GAMI tests were all with Beechcraft panels. Beech is known for quality. Who knows about the paint systems used by Cessna, Piper, Mooney, etc.

Or by the myriad of paint shops, good and bad.

It really looks to me that the primer was attacked.  The top coat seems to be intact.

[Pinecone]

2 hours ago, Marc_B said:

I think that it seems that the G100UL test with the 100LL sample that had "high toluene" may have been intended to show that 100LL with high toluene caused paint damage whereas the G100UL sample showed didn't??  I was very curious why GAMI wouldn't just test 100LL vs G100UL...why not just a simple "pumped fuel" vs "pumped fuel"??  Why add more toluene to one of the fuels, especially when the amount and concentration wasn't labeled?

As has been pointed out time and time again, 100LL is not the same from refinery to refinery.  Those that put out a lower quality (for our purposes) alkylate need to use more aromatics to meet the spec.

100LL is not A product.  It is a range of possible mixtures that end up meeting the spec.

So George tested his local 100LL.  And he tested a high aromatic 100LL.  This could either come from another airport fed by a different refinery, or add aromatics to the local 100LL

This is also why those clamoring for an ASTM spec for G100UL do not understand specs.

An ASTM spec does not specify exact mixture to make Product A.  Say rum.  It specifies using ranges of various ingredients to come up with a rum.  Might be the same as Bacardi, but might be Captain Morgan.  Not the same, but still rum.

[Marc_B]

I guess the hard truth is that the multiple threads and hundreds of posts about G100UL haven't really added much clarity, controlled test data, or underlying scientific data one way or the other.  We have YouTube videos for both sides of the coin with multiple people presenting observational data to an inquisitive public, on a public forum, that just leads to more questions about details that may, or may not, be known.  We've only been presented observational, anecdotal evidence rather than controlled studies.  (not to suggest that this wasn't required for FAA Certification as I suspect that it was, and should be, and was hopefully very thorough)

Trying to figure out how to protect staining, if you should worry about damage to paint, what parts of your fuel system has nitrile components and if this even makes one bit of difference...  These are all questions that get generalized answers to specific questions; which leads to tons of speculation as we all try to learn more about this new reality that is coming regardless of if you like it, agree with it or feel like it's long overdue.

The "tone" of the questions/comments are also tainted in the underlying sentiment of whether you are a fan of unleaded fuel mandates or not.  So of course by nature these threads have political undertones as well.  Unfortunately, political discussions often go in circles because there are various sides of the argument and they're usually both right and both wrong.

In having public discourse on a (somewhat) anonymous forum, there will usually be critical questions, there may be apparent "trolls" and skeptics, and there may be vocal fans.  But majority of the Mooneyspace visitors and members (including myself) come to learn from each other how to be safer pilots and better take care of a great aircraft.

[MikeOH]

4 hours ago, George Braly said:

Those panels were from aircraft that had been repainted in the field by various different paint shops.   

Further - - we know - - with certainty - -  that  various production runs of 100LL will do exactly the same thing to the paint as is depicted in the Mooney example - -  if the paint quality is poor.  

Can we use that fact as a baseline ?

@George Braly

Sure, I accept that some blend of 100LL may well cause issues with some paint.

The fact that we would like you to acknowledge is that IN THE VIDEO, 100LL does NOT strip whatever that paint is, but G100UL DOES!

Can we use that fact as a baseline, as well?

[Z W]

14 hours ago, MikeOH said:

The fact that we would like you to acknowledge is that IN THE VIDEO, 100LL does NOT strip whatever that paint is, but G100UL DOES!

Can we use that fact as a baseline, as well?

We have two videos with what appear to be contradicting "facts". Somewhere, there's a scientific explanation for it. I don't think anyone knows what it is yet. In science there is no such thing as a "baseline" fact. Just ideas and theories.

Mr. Braly and GAMI have posted their video with their names and their company name behind it and come here to answer questions about it. They've had their testing of G100UL independently verified by the FAA, as far as I can tell. I've seen Mr. Braly from a distance speaking on G100UL at Oshkosh workshops and I'm pretty sure he's a real person involved in this industry for many decades.

The other video you reference as fact was posted as an unlisted video under an anonymous internet alias. All of the spoken "facts" in it are a from a faceless, nameless voice off-camera. He hasn't come to Mooneyspace to answer any questions. I don't think we know much of anything for sure based on his video.  Is it a reason to ask questions and engage in further testing? Sure. Can we use it as a "baseline" or "fact"? No, not reasonably. Demanding that anyone accept it as fact is also unreasonable. Do we really know that the substance in the video was G100UL, or that the paint was Jet-Glo?

[A64Pilot]

I called someone the other day that I figure has some knowledge on this subject. He wasn’t in the office but called me back today

We talked awhile and pointed me to this Website and told me that Gami did not participate in this testing.

https://www.faa.gov/sites/faa.gov/files/PAFI_Fuel_Development_Testing_Lessons_Learned.pdf

 

Edited 19 hours ago by A64Pilot

[MikeOH]

8 minutes ago, Z W said:

We have two videos with what appear to be contradicting "facts". Somewhere, there's a scientific explanation for it. I don't think anyone knows what it is yet. In science there is no such thing as a "baseline" fact. Just ideas and theories.

Mr. Braley and GAMI have posted their video with their names and their company name behind it and come here to answer questions about it. They've had their testing of G100UL independently verified by the FAA, as far as I can tell. I've seen Mr. Braley from a distance speaking on G100UL at Oshkosh workshops and I'm pretty sure he's a real person involved in this industry for many decades.

The other video you reference as fact was posted as an unlisted video under an anonymous internet alias. All of the spoken "facts" in it are a from a faceless, nameless voice off-camera. He hasn't come to Mooneyspace to answer any questions. I don't think we know much of anything for sure based on his video.  Is it a reason to ask questions and engage in further testing? Sure. Can we use it as a "baseline" or "fact"? No, not reasonably. Demanding that anyone accept it as fact is also unreasonable. Do we really know that the substance in the video was G100UL, or that the paint was Jet-Glo?

It was George that started the "baseline fact" claim, not me.  

You comment that there's "no such thing as a baseline fact" yet you seem ready to accept GAMI's test as valid and the contradictory test video as possibly fake!  THAT is not a very scientific approach, in my opinion.

The video test I viewed seemed very well thought out and performed, as I'm sure GAMI's was.  I believe both to be legitimate tests/experiments.  The missing information are the details of primers, paints, 100LL formulation, and test methods.

[GeeBee]

My father used to admonish me, "believe none of what you hear and half of what you see". The stakes here are so huge I would not be surprised there is subterfuge by any number of parties. As mentioned there is only one party so far that I have seen that has their testing verified by an independent party and indeed regulatory agency. I certainly welcome more testing, but it has to be more than a YouTube video. There are any number of independent test organizations that could perform the requisite tests. Of course engagement and payment would need to be by an interested but independent party like ABS, NBAA or EAA.

[Andy95W]

50 minutes ago, A64Pilot said:

I called someone the other day that I figure has some knowledge on this subject. He wasn’t in the office but called me back today

We talked awhile and pointed me to this Website and told me that Gami did not participate in this testing.

https://www.faa.gov/sites/faa.gov/files/PAFI_Fuel_Development_Testing_Lessons_Learned.pdf

 

Is that the study @George Braly said they pulled out of because somebody there was attempting to infringe on the G100UL patent?

I’m not pro or con anything here, but I’m definitely against theft of intellectual property and patent infringement. 

Edited 19 hours ago by Andy95W

[GeeBee]

7 hours ago, George Braly said:

 

Mark,

You are right.  I have said that.  I, personally,  have never seen G100UL strip aircraft paint which had been applied in a manner consistent with standard aircraft paint shop practices.     That was the basis and context for my statement.  

I am not, in any way, trying to engage in what you call "double speak." 

I have seen our local FBO 100LL damage (leave a bare spot of aluminum)  when it was dripped (for several days) onto a surface on an aircraft that was not painted with standard aircraft quality paint.   

I note that there would have been "better ways" to address the subject than accusing me of "double speak". 

If the good folks in this "MooneySpace"  continue to attack my personal integrity - -  then I will withdraw from further participation. 

Regards, 

George 

They have called me everything but a "child of God" on this site Mr. Braly. I understand your frustration, you have proven G100UL ad-infinitum, and I am sure there is abundant subterfuge against you and your product for all kinds of nefarious reasons.  Remember the old adage, the dogs bark, but the caravan moves on. 

[A64Pilot]

5 minutes ago, Andy95W said:

Is that the study @George Braly said they pulled out of because somebody there was attempting to infringe on the G100UL patent?

I’m not pro or con anything here, but I’m definitely against theft of intellectual property and patent infringement. 

I have no idea, just was told they didn’t participate

I guess that pretty much defines here say, doesn’t it.

If you go back in one of these threads I was calling BS on the Youtube video before I even saw it, because most of Youtube is BS, people trying for their 30 sec of fame or whatever drives all of that crap like idiots parachuting out of a rare antique airplane for instance

But I finally did view the video and I’ve done aircraft testing for most of my adult life and while it wasn’t lab level testing, I can tell you most of aircraft testing isn’t. I heated fuel for hot fuel testing with a Turkey fryer, an automatic transmission cooler, 50’ of fuel line and a fuel pump for instance with my Fluke recording fuel temp. You would believe how we tested for fuel pressure / flow in worst case nose up, min fuel.

Anyway I think his testing was pretty good actually, and unless he rigged the tests for his 30 sec of fame, which I don’t think he did, because that type as soon as they get a crowd really go into overdrive, but this guy hasn’t that I’m aware of, so I don’t think he has an agenda. 

Anyway in my opinion, which of course is all any of us can state, there is enough hear say data that if at all possible I won’t use this stuff, I’ll avoid flying to locations where it’s the only fuel and if I lived where it was I’d get my fuel supply by whatever means necessary.

The fuel staining isn’t by itself real concerning as Auto fuel also stains brown, my C-140 fuel caps have two holes in them, that the fuel vent and if topped off fuel gets sucked out onto the wing and it stains, but those stains do polish off. It just seems anything that gets into Jet-Glo and gets inside of the paint to where it can’t be polished off is in my opinion having some kind of reaction with the paint.

O-rings aren’t the issue to me, the issue is bladders, tank sealant, and all kinds of components that have rubber and plastics in them that you can’t upgrade to Viton, like pumps, fuel servos, fuel flow meters, fuel pressure transducers, valves and I’m sure there are other items that I’ve missed.

 

Edited 18 hours ago by A64Pilot