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

[A64Pilot]

If there are tanks, they alodined, and the pic of the tail is clearly alodined.

We had I think 5 tanks at Thrush each probably 4x8x30 feet. 

Going from memory first tank was an acid that cleaned and degreased as in finger prints etc

Second tank was to neutralize the acid

Third tank was a rinse tank

fourth tank was Alodine

Fifth tank was another rinse tank.

That’s from memory so I may not be exact but to alodine the metal needs to be very clean.

Being in a dry area I didn’t expect Mooney to alodine. I flew an AH-64 to the plant in maybe 89 and toured it and don’t remember tanks, but then in 89 I probably wouldn’t have known what they were unless I was told as I had no experience with manufacturing then.

Being alodined Mooney’s shouldn’t have nearly as much of an issue with aluminum part corrosion that they seem to.

Edited Tuesday at 07:26 PM by A64Pilot

[Marc_B]

@A64Pilot if you look in the pictures, that’s basically what the lineup was. 
alkaline cleaner; rinse; rinse with exiting spray; deoxidizer, rinse; rinse with exiting spray; M-CR 1200S Alodine; rinse with exiting spray.

@shawnd thanks for the pics showing skin surfaces with alodine. Curious if any of you know the history of treatments and paints with Mooney over the years? I know some years were better paint than others. I always thought that was the difference in paint shop personnel vs products? 

[shawnd]

I don't have the historical details, but we could reach out to Frank Crawford at Mooney or someone knowledgeable on the topic. Maybe @LANCECASPER knows someone?

While we now see Alodine-treated tanks and more recent model year skins treated, it's unclear when these techniques were first implemented on the assembly line.

[mluvara]

10 hours ago, Pinecone said:

This is what I said after your first video.  It appeared that the failure was at the primer layer.

And also, I was saying that it seemed to be an issue with low volatility components concentrating.

What would be good now it to test using your methods some parts over various primers and top coats, where the actually product used for each layer is known.

My suspicions are that single part primers are the issue and why some airplanes have paint issues, and others (like the AOPA Baron) do not, even with leaks.

The interesting thing in this whole discussion is people are talking about "What's the correct paint?". The answer is there is no mandated paint system (defined as primer+topcoat) for aircraft, unless the manufacturer has one in a maintenance manual. To say that primer/paint that is getting deteriorated with G100UL is improper or inferior is setting a new standard that did not exist with 100LL. 

I'm sure you saw it (and some might disagree), but in Video #2, I evaluated the areas of the AOPA Baron and there appeared to be areas of paint deterioration similar to my testing along the edges between Nov 2023 and at Oshkosh 2024.

And what about the affected Cirrus? Does Cirrus use inferior primer and paint systems?  Photo taken today. Note: loose paint was rubbed away since observation in Video #3.

Edited Wednesday at 01:00 AM by mluvara
Cirrus photo annotation

[shawnd]

Re: cirrus - ouch 

[gabez]

6 minutes ago, shawnd said:

Re: cirrus - ouch 

that is gnarly. I thought mine was the worst....

[A64Pilot]

Re Cirrus, I would be afraid that paint is the least of their worries. 

What made the Cirrus leak? They don’t have bladders do they? I assumed the tanks were integral?

More often than not anything that dissolves Jet-Glo will also dissolve composites, although I don’t know with what or how a Cirrus is made. I would assume prepeg and an Autoclave, but as they don’t interest me I haven’t looked.

I know only some paint remover can be used to remove paint on boats, some will dissolve even Epoxy boats, so fiberglass safe remover has to be used or way more common mechanical removal

Epoxy boats are ALL painted, you can’t Gelcoat epoxy, not sure why

Edited Wednesday at 01:25 AM by A64Pilot

[IvanP]

The damage to the Cirrus looks like it could affect the plane's airworthiness. Just curious about the product liability issues that may be involved in this scenario. If a "drop-in" replacement fuel approved by the FAA renders planes unairworthy what will the agency's response be? Who is liable for the damage? I can see some lawsuits coming up in the near future.

Let's just hope that we can stop the govt mandate to use this fuel. So long as we have a choice whether or not to experiment with G100UL or other UL fuels in our planes, it is up to the owners to evaluate the risk and decide. Once it becomes the only option available, we are in some deep $%^&.

Edited Wednesday at 01:35 AM by IvanP

[MikeOH]

1 hour ago, IvanP said:

Let's just hope that we can stop the govt mandate to use this fuel. So long as we have a choice whether or not to experiment with G100UL or other UL fuels in our planes, it is up to the owners to evaluate the risk and decide. Once it becomes the only option available, we are in some deep $%^&.

^^^ THIS 1000%. ^^^

GAMI should be free to sell G100UL...and I should be free to NOT buy it!

[redbaron1982]

1 hour ago, IvanP said:

The damage to the Cirrus looks like it could affect the plane's airworthiness. Just curious about the product liability issues that may be involved in this scenario. If a "drop-in" replacement fuel approved by the FAA renders planes unairworthy what will the agency's response be? Who is liable for the damage? I can see some lawsuits coming up in the near future.

Most likely lawyers are going to try to "collect" from everyone somehow involved, but I guess the one that is ultimately liable is the owner of the STC that made it legal to the owner/operator to fly using G100UL.

[gabez]

1 hour ago, IvanP said:

So long as we have a choice whether or not to experiment with G100UL or other UL fuels in our planes, it is up to the owners to evaluate the risk and decide. Once it becomes the only option available, we are in some deep $%^&.

sorry but I disagree with this statement. I am not qualified (nor I want to be) to experiment with any fuel or any aircraft. I want to fly a certified aircraft that runs on a certified/approved (what ever is the term) fuel. And, I need it to be safe. 

[Marc_B]

2 hours ago, mluvara said:

The interesting thing in this whole discussion is people are talking about "What's the correct paint?".

My curiosity of where this fails isn’t to minimize the damage of the unfortunate aircraft and their owners, but to learn what the future of unleaded fuel might hold. With aircraft that require higher octane fuel this has to come from somewhere. Be it aromatics, metallics, or oxygenates??  But there’s a very real chance that at some point we may uncover that certain elastomers, materials, compounds and treatments may be more resilient. The hard lessons learned today might save a lot of aircraft “tomorrow.”

Currently there’s no way I’d want to use this in my Mooney. Unfortunately I don’t see clarity and answers forthcoming.

[varlajo]

10 minutes ago, Marc_B said:

With aircraft that require higher octane fuel this has to come from somewhere. Be it aromatics, metallics, or oxygenates??  But there’s a very real chance that at some point we may uncover that certain elastomers, materials, compounds and treatments may be more resilient.

John Deakin, 1999: "When lead is needed, there is NO known practical (chemical) substitute, and none is likely to be found. The big petroleum companies have MAJOR reasons to find a fix (cost), and they and the FAA have been searching and experimenting very hard for nearly 10 years, at great expense. With no results. I've been to a lot of seminars where representatives from the petroleum companies stand up and expound for an hour, when they could have saved a lot of time by standing up and simply saying, "There has been no progress in this area," and sitting down again."

[Schllc]

This issue needs a novel approach. 
the FAA needs to get its head out of its 18th century ass and make  it easier to certify a new engine, that can have variable electronic ignition and eliminate the need for leaded fuel. 
Designing a new fuel is obviously a poor solution/approach
we have the technology already…

[LANCECASPER]

4 hours ago, shawnd said:

I don't have the historical details, but we could reach out to Frank Crawford at Mooney or someone knowledgeable on the topic. Maybe @LANCECASPER knows someone?

While we now see Alodine-treated tanks and more recent model year skins treated, it's unclear when these techniques were first implemented on the assembly line.

Around 2006 Mooney started a new process of sealing tanks, I believe using sealant on components as the tanks were being assembled rather than waiting until after to seal the tank.  I've heard that the long term results have proven much better. 

[IvanP]

2 hours ago, Schllc said:

This issue needs a novel approach. 
the FAA needs to get its head out of its 18th century ass and make  it easier to certify a new engine, that can have variable electronic ignition and eliminate the need for leaded fuel. 
Designing a new fuel is obviously a poor solution/approach
we have the technology already…

Certification of new engines with 21st century technology would be great and I hope that it will happen soon. However, even it it does happen tomorrow, it is unlikely to be a practical solution to the UL fuel compatibility issues we are facing now as most owners of piston aircraft would probably not be able to write a six figure check for a new engine when their current engines and fuel are operating as designed, nor should they be forced to do so. 

Given the current lead times for new or overhauled engines and engine components, we are talking about years of lead time even if the FAA certifies new engines. 

[Pinecone]

13 hours ago, mluvara said:

The interesting thing in this whole discussion is people are talking about "What's the correct paint?". The answer is there is no mandated paint system (defined as primer+topcoat) for aircraft, unless the manufacturer has one in a maintenance manual. To say that primer/paint that is getting deteriorated with G100UL is improper or inferior is setting a new standard that did not exist with 100LL. 

I'm sure you saw it (and some might disagree), but in Video #2, I evaluated the areas of the AOPA Baron and there appeared to be areas of paint deterioration similar to my testing along the edges between Nov 2023 and at Oshkosh 2024.

And what about the affected Cirrus? Does Cirrus use inferior primer and paint systems?  Photo taken today. Note: loose paint was rubbed away since observation in Video #3.

Is that the plane that had the different sealant?

Again, unless we know what paint system was used when it was last painted, we may be comparing apples with beef.

No, that does not help those with issues, but it can lead to a better understanding of what is going on.

[Fix]

I really had high hopes for G100UL.

But what I've seen and read about the problems I'm amazed that GAMI hasn't tested their fuel properly.
I don't care what paint a Baron has, it crazy that they didn't test on several aircraft brands to see if there was any issues.
Also with sealants and O-rings problems.

I can understand that GAMI "rushed" with their product to be available on the market and they want to have G100UL Commercially available in this race.

This is major mistake from their side, and i think Swift already on their website points out the problem with G100UL.

If there is not any "sabotage" from some other interested party in this race then GAMI will most likely have big problems ahead.

Who will pay for all this damage to aircraft owner paint, and that Cirrus fuselage damage.
This could turn into a nightmare for GAMI and in the end out of business.

Until things has been resolved I will never put G100UL in my aircraft (I can't since G100UL is not available in Europe yet).

[exM20K]

10 hours ago, Schllc said:

This issue needs a novel approach. 
the FAA needs to get its head out of its 18th century ass and make  it easier to certify a new engine, that can have variable electronic ignition and eliminate the need for leaded fuel. 
Designing a new fuel is obviously a poor solution/approach
we have the technology already…

Yes,but…

The challenges of creating a “modern” aero engine are significant. Deltahawk, for example. 

Diamond, Thielert, and Austro have had commercial success converting automotive diesels for aero use, but the problems have been, and remain, ever-present.

The 1.7 Thielert first generation engines had issues with snapped piston cooling nozzles and cracked heads.

The 2.0 Thielert (Continental) were better but had some fuel system issues.

The Austro engines started strong but now are operating under a 50 hour borescope mandatory service bulletin to look for cracked pistons with only a promise of a fix in the near future.

SMA flopped for reasons I don’t know.

Turbines don’t scale down to a 200HP size well.

I enjoyed a Wankel in an early 80’s Rx7 but don’t think I’d want to fly behind one.

So, tackle all these challenges for a market size as tiny as GA?

Meanwhile, what we have in the low-RPM air-cooled spark-ignition aero engines, work pretty well. Yes, continentals need cylinders every 1000 hours, and yes, Lycoming has had materials and manufacturing defects, but these engines work in the existing fleet of airframes. Redbird fit some 172’s with SMA or Continental diesels, and Piper put Continental diesels in some archers. Mr. Market rejected both.

If a new suite of engines can’t power our fleet, then vigorously defending 100LL until a viable substitute fuel is found is the only way I see to preserve our investments and freedom of flight.

-dan

[N201MKTurbo]

The only way to make our engines work on a reasonable unleaded fuel (UL94) is to reduce the cylinder pressure. This can be done with a MP limitation, a timing reduction or lower compression pistons. All of these things will reduce the engine power a bit. There is no modern computer magic that can change any of this.

[N201MKTurbo]

I would think that Lycoming could make a 200HP version of the IO-390 that could burn 94 UL.

[mluvara]

15 hours ago, A64Pilot said:

Re Cirrus, I would be afraid that paint is the least of their worries. 

What made the Cirrus leak? They don’t have bladders do they? I assumed the tanks were integral?

More often than not anything that dissolves Jet-Glo will also dissolve composites, although I don’t know with what or how a Cirrus is made. I would assume prepeg and an Autoclave, but as they don’t interest me I haven’t looked.

I know only some paint remover can be used to remove paint on boats, some will dissolve even Epoxy boats, so fiberglass safe remover has to be used or way more common mechanical removal

Epoxy boats are ALL painted, you can’t Gelcoat epoxy, not sure why

 

2 hours ago, Pinecone said:

Is that the plane that had the different sealant?

Again, unless we know what paint system was used when it was last painted, we may be comparing apples with beef.

No, that does not help those with issues, but it can lead to a better understanding of what is going on.

I will quote Cirrus's Feb 5 release

"We are actively engaged with a Cirrus owner who began using GAMI G100UL in November 2024 and has since observed paint degradation, seal degradation, and fuel leakage. Cirrus is working with the FAA and the aircraft owner to conduct further investigation and testing."

This aircraft is from Reid Hillview (RHV) and my understanding is that this is a 2010 model with original factory paint and seals (I have not personally inspected the logs), which uses wetted wings. I believe what GAMI references on their website was a factory aircraft used for testing with GAMI. Whether or not the affected Cirrus at RHV and the factory aircraft GAMI mentions have any similarities, I do not know. 

Note: I would assume the aircraft had its appropriate re-pack of the chute at the 10 year mark. I am not aware if they repaint the entire aircraft (including the bottom of the wing) or just the affected areas for the re-pack.

As to paint, I expect Cirrus has utilized quality paint throughout the production of their aircraft and as best as I can tell, currently utilizes Sherwin Williams.

Edited Wednesday at 04:43 PM by mluvara

[Schllc]

2 hours ago, exM20K said:

Yes,but…

The challenges of creating a “modern” aero engine are significant. Deltahawk, for example. 

Diamond, Thielert, and Austro have had commercial success converting automotive diesels for aero use, but the problems have been, and remain, ever-present.

The 1.7 Thielert first generation engines had issues with snapped piston cooling nozzles and cracked heads.

The 2.0 Thielert (Continental) were better but had some fuel system issues.

The Austro engines started strong but now are operating under a 50 hour borescope mandatory service bulletin to look for cracked pistons with only a promise of a fix in the near future.

SMA flopped for reasons I don’t know.

Turbines don’t scale down to a 200HP size well.

I enjoyed a Wankel in an early 80’s Rx7 but don’t think I’d want to fly behind one.

So, tackle all these challenges for a market size as tiny as GA?

Meanwhile, what we have in the low-RPM air-cooled spark-ignition aero engines, work pretty well. Yes, continentals need cylinders every 1000 hours, and yes, Lycoming has had materials and manufacturing defects, but these engines work in the existing fleet of airframes. Redbird fit some 172’s with SMA or Continental diesels, and Piper put Continental diesels in some archers. Mr. Market rejected both.

If a new suite of engines can’t power our fleet, then vigorously defending 100LL until a viable substitute fuel is found is the only way I see to preserve our investments and freedom of flight.

-dan

Dont disagree with this at all, however...

Your entire premise is predicated on the profitability and roi for manufacturers to build and deliver these engines.  I just replaced an engine in a sprinter van for my company that came complete, with turbo and exhaust for 11k.  Granted these engines are made in much higher quantities, but the second major factor is the approval process.  

The FAA needs to find a more efficient way to approve things for our planes.  The clutch backspring is a great example.  This is a $10 part at best, but the regulations are so onerous and obtuse that someone has to charge 2500 to make it work.

There has to be a spot in the middle that works, there is no reason that our part 91 aircraft should have to meet some of these standards for parts.  The only justification/explanation for this process remaining the way it is, is to either eliminate GA pistons completely, or rank incompetence. 

I personally believe it is the unspoken mission to eliminate all of our annoying little piston planes, and they are engaging in a war of attrition by just making it so stupid expensive, that even people with the money to burn can't swallow the pill.

Replacement engines are not a simple solution, but 40years of whining about a replacement fuel hasn't gotten us anywhere so far, so at what point do you look for a different path?

Or, just accept the FACT that the scant amount of lead our engines burn is like spitting in the ocean and saying you raised sea levels.  Technically it may be true but really?

[mluvara]

12 hours ago, Marc_B said:

My curiosity of where this fails isn’t to minimize the damage of the unfortunate aircraft and their owners, but to learn what the future of unleaded fuel might hold. With aircraft that require higher octane fuel this has to come from somewhere. Be it aromatics, metallics, or oxygenates??  But there’s a very real chance that at some point we may uncover that certain elastomers, materials, compounds and treatments may be more resilient. The hard lessons learned today might save a lot of aircraft “tomorrow.”

Currently there’s no way I’d want to use this in my Mooney. Unfortunately I don’t see clarity and answers forthcoming.

Understood and agree about the fact that learnings here are invaluable.

I guess I was responding to a lot of the discussion on the net where people were blaming the paint type and quality. I'm sure that I'm not alone in the belief that I currently won't tolerate the notion that I have to repaint prior to using a new fuel, or repaint because of spilled fuel. I might as well just fly polished aircraft. 

I started this testing by using painted surfaces from personal aircraft. My Citabria has the same paint on the cowling (which frequently gets drips out of the bottom) as the inspection panels have. I'm not interested in repainting the aircraft at this time just because a fuel may require that. And I still have many open questions about the effect on fabric and long term effects on other materials. 

 

[IvanP]

1 hour ago, N201MKTurbo said:

The only way to make our engines work on a reasonable unleaded fuel (UL94) is to reduce the cylinder pressure. This can be done with a MP limitation, a timing reduction or lower compression pistons. All of these things will reduce the engine power a bit. There is no modern computer magic that can change any of this.

In other words, take well runnig high compression high performance engines and hobble them to perfom like C-172 at the altar of the environmetalist gods