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

[gabez]

9 hours ago, EricJ said:

That seems to be a positive development.  I hope it winds up being broadly applicable.

it's progress from a company that actual makes fuel for living.

I think we have supplies of paint stripper for the next decade. Hopefully GAMI cuts a deal with Home Depot so it's more readily accessible. 

[MisfitSELF]

On 8/24/2025 at 9:47 AM, Aaviationist said:

No, you paid 400$ for an STC allowing you to use the fuel covered under the STC. 
 

are you saying Gami or someone prevented you from using the fuel?

 

how much of the STC’d fuel have you run through your engine?

For one thing the fuel isn't available on any wide scale and likely won't be because of these issues.  And is was advertised to cause no issues and be a "drop in replacement".  It's not that, it's not as advertised, and I'm out $400.  It's not really much in the aviation scheme of things but those are real damages.  I paid for a product, it turns out is vaporware and even if I could get it, would likely result in damage to my aircraft.  You damn right I want my money back. 

You order some $400 product on Amazon based on reviews, turns out all the "5 star reviews" are false advertising and the product doesn't work or causes harm, would you just suck it up or return it?

[MikeOH]

29 minutes ago, MisfitSELF said:

You order some $400 product on Amazon based on reviews, turns out all the "5 star reviews" are false advertising and the product doesn't work or causes harm

BINGO!

Product misrepresentation, plain and simple.  The idea that you shouldn't expect to recover those damages is almost as ridiculous as claiming that the $400 isn't even damages in the first place!  You paid for a "license" to use a misrepresented product...damn right I'd want my money back.

[Aaviationist]

15 hours ago, MikeOH said:

BINGO!

Product misrepresentation, plain and simple.  The idea that you shouldn't expect to recover those damages is almost as ridiculous as claiming that the $400 isn't even damages in the first place!  You paid for a "license" to use a misrepresented product...damn right I'd want my money back.

Circle talk Mike strikes again. 
 

 

[gabez]

On 9/4/2025 at 7:33 AM, PT20J said:

Can you get data for the 100LL pumps for comparison?

I just got the data from the county. KWVI sells, on average, 11,600 gallons of 100LL per month

[MikeOH]

Anyone have recent updates on the G100UL situation?

Current data on sales volumes at RHV, WVI, and anywhere else it's available?

Seems like there might be updates on the Consent Decree case, as well.  IIRC, there was some possibility of appeals, or some such.

[haymak3r]

Has anybody watched the podcast with gami, and savvy? I don't recall it mentioned at all regarding the multitude of reports about paint, etc with g100ul. Are they really just going to ignore this? Basically, if you have a slight fuel leak, or any gets on any paint at any time. Then we should just expect our paint to be ruined? 

[Paul Thomas]

The FAA seems to be getting more serious about the end of 100LL.

G100UL seems to have been really quiet. You'd think with as much product as they are sitting on, they would want to move it given the cost of storage and cost capital tied up. I'm surprised it hasn't been discounted to see if more people would adopt it. Getting people to adopt it is so important to having other believe in the product and getting first mover advantage.

At some point, I'd imagine we are going to have to make choices that please none of us.

[MikeOH]

3 minutes ago, Paul Thomas said:

G100UL seems to have been really quiet. You'd think with as much product as they are sitting on, they would want to move it

Exactly!  That's what prompted me to revisit this; seems weird...I don't really follow any other aviation fora, so I have no idea if the topic is being actively discussed elsewhere??

[GeeBee]

28 minutes ago, haymak3r said:

Has anybody watched the podcast with gami, and savvy? I don't recall it mentioned at all regarding the multitude of reports about paint, etc with g100ul. Are they really just going to ignore this? Basically, if you have a slight fuel leak, or any gets on any paint at any time. Then we should just expect our paint to be ruined? 

Yes, I did watch it. George Braly said basically Mooneys and twin Cessnas with integral tanks are leaking fuel storage devices. He said, they have always leaked and will continue to leak no matter the fuel. He said they leak with 100LL at the same rate as with G100UL.

[Paul Thomas]

Just now, MikeOH said:

Exactly!  That's what prompted me to revisit this; seems weird...I don't really follow any other aviation fora, so I have no idea if the topic is being actively discussed elsewhere??

The thread was revived on Beechtalk last week when the FAA published their going away from 100LL but it had otherwise been silence for months.

[Marc_B]

@haymak3r The podcast was really about Braly's work with LOP, Aircraft Pilot Seminars, and the development of their test cell.  Braly did mention that "people say G100UL causes fuel leaks...well Mooneys have been leaking 100 low lead for 30 years" to which Busch chuckled, and dismissed concerns as nothing new to see here.  Nothing mentioned about paint or other material issues.

Braly still posts on BeechTalk and most "advertising" for G100UL is more of trying to discredit his competitors.  I've not seen any new information since rollout.  No new materials testing.  The slide GAMI still uses (posted by Braly 1/18/26) shows about 125 aircraft using G100UL and 10 having issues that are described as "inservice seepage issues - net of known preexisting 100LL seepage."

Braly's post on 1/18/2026 was "There were about 11 or 12 reports ( I do not remember with looking it up) of aircraft with some type of leakage of G100UL or, in a couple of instances, other issues."

I'm not sure there will be any more to update...my guess is holding off to try to bide time till 2030 or another legal mandate for a ban.

[George Braly]

35 minutes ago, haymak3r said:

Has anybody watched the podcast with gami, and savvy? I don't recall it mentioned at all regarding the multitude of reports about paint, etc with g100ul. Are they really just going to ignore this? Basically, if you have a slight fuel leak, or any gets on any paint at any time. Then we should just expect our paint to be ruined? 

There are several Mooneys that have used G100UL Avgas.   No leaks and no paint damage.  

I borescoped the fuel tank of one Mooney that had leaked.  There were at least two (likely three) different types of internal sealant applications (wrong sealant - wrong technique) clearly visible where someone had tried to do field repairs of earlier 100LL leakage.   There are three shops around the country that specialize in stripping the interior fuel tank sealant and then applying new sealant - - - properly applying new sealant.  (Note the factory applied sealant was never properly applied by the factory - - according to the repair shops.)

Basically, those repair shops tell us that any Mooney with more than about 20 years since factory sealant is a ticking leak-bomb for fuel leakage. 

I inspected a Mooney at RHV that had been using G100UL Avgas for several months.  No evidence of any issues.  I asked the owner if I could borescope his fuel tanks.  He grinned and approved.   When I looked in the tank the sealant was as pristine and perfect as you could ever expect.   

When I quizzed the owner, he grinned and told me that his plane started leaking 100LL when it was about 15 years old.  He had it resealed about 8 years previous - - at  "Weep No More"  (shop in Minnesota that specializes in resealing fuel tanks.) 

                                         ***********

There are about 150 aircraft that have used G100UL Avgas.   Of that number, there are 5 that have reported in-service issues that did not have clear evidence of prior leakage of 100LL.   

If you spill G100UL on your wing during refueling - - and clean it up  ("Good fuel hygiene") before it evaporates and dries out in sunlight) then it does no damage to the paint.   If you spill it and let it sit and evaporate for a while, without cleaning it up, then it will slightly stain the paint a brownish color. 

Various ones of the popular crystal coatings offer substantial protection of the paint.

A couple of those commercial products are extremely effective at protecting the paint from stains and damage and have a number of other general benefits with respect to improving the durability of the paint and greatly enhancing the ability to clean  bugs and debris from the wings. 

George

[redbaron1982]

What about the Cessna 421 that was totalled by the insurance company after all the damages caused by G100UL? I'm really curious about it. 

I'm baffled about the ongoing denial by GAMI on all the issues people are having after using G100UL. If GAMI would be more transparent I would be open to using it, but their denial is a safety of flight issue.

[varlajo]

- Your toothpaste dissolves teeth.
- With appropriate oral hygiene, teeth are not dissolved. 
- Here are statements from users whose teeth have dissolved. 
- With appropriate oral hygiene, teeth are not dissolved. 
- Here is evidence that a tooth placed in your toothpaste dissolves.
- With appropriate oral hygiene, teeth are not dissolved. 
- I hear Colgate makes decent toothpaste now.
- Colgate toothpaste can't exist in principle. 

[Justin Schmidt]

19 minutes ago, varlajo said:

- Your toothpaste dissolves teeth.
- With appropriate oral hygiene, teeth are not dissolved. 
- Here are statements from users whose teeth have dissolved. 
- With appropriate oral hygiene, teeth are not dissolved. 
- Here is evidence that a tooth placed in your toothpaste dissolves.
- With appropriate oral hygiene, teeth are not dissolved. 
- I hear Colgate makes decent toothpaste now.
- Colgate toothpaste can't exist in principle. 

What kind of alcohol was that from, i would like some 

[EricJ]

1 hour ago, Marc_B said:

@haymak3r The podcast was really about Braly's work with LOP, Aircraft Pilot Seminars, and the development of their test cell.  Braly did mention that "people say G100UL causes fuel leaks...well Mooneys have been leaking 100 low lead for 30 years" to which Busch chuckled, and dismissed concerns as nothing new to see here.  Nothing mentioned about paint or other material issues.

The more those guys talk that way the more I lose respect for both of them.   Likewise Scott Perdue.    It's pretty much gaslighting at this point, in my opinion.

27 minutes ago, redbaron1982 said:

What about the Cessna 421 that was totalled by the insurance company after all the damages caused by G100UL? I'm really curious about it. 

That seemed to put a pin in a lot of the discussions about it, and things seemed to go pretty quiet after that since I think it was an easy decision point for many people.   It seemed like there wasn't much left to discuss after that for a lot of folks.

15 minutes ago, varlajo said:

- Your toothpaste dissolves teeth.
- With appropriate oral hygiene, teeth are not dissolved. 
- Here are statements from users whose teeth have dissolved. 
- With appropriate oral hygiene, teeth are not dissolved. 
- Here is evidence that a tooth placed in your toothpaste dissolves.
- With appropriate oral hygiene, teeth are not dissolved. 
- I hear Colgate makes decent toothpaste now.
- Colgate toothpaste can't exist in principle. 

- It only dissolves teeth in people with bad teeth.

- It dissolves teeth in 30% of the population!

- That 30% had bad teeth.   70% of the population can use it with no trouble.

- It dissolved my teeth and my kids teeth!

- You should have taken better care of your teeth.   The majority of the population are fine with it.

If that were spark plugs or tires or paint or oil or anything else (toothpaste) the manufacturers would be scrambling to fix the problems and make those damaged as whole as possible, but there seems to be a really good supply of hubris to go around for this one.

[varlajo]

1 minute ago, EricJ said:

The more those guys talk that way the more I lose respect for both of them.   Likewise Scott Perdue.    It's pretty much gaslighting at this point, in my opinion.

I tend to agree, unfortunately. GAMI injectors were a revolutionary advancement, and a few their other bits and bobs are quite successful as well. In fact, I've been looking forward to the release of their backup alternator. But the G100UL story is nothing short of farcical. 

[Justin Schmidt]

9 minutes ago, EricJ said:

The more those guys talk that way the more I lose respect for both of them.   Likewise Scott Perdue.    It's pretty much gaslighting at this point, in my opinion.

I have come to that,also,over the last year. He had a clear point in time to be transparent and involve others. Scott seems to just run ads for him.

For mike, how he and everyone thinks he came up with everything aviation, a spotlight fool that has never touched a wrench

[varlajo]

12 minutes ago, Justin Schmidt said:

What kind of alcohol was that from, i would like some 

You'd need an STC and a placard. And a special mat! 

[Andy95W]

I was a supporter and advocate for G100UL from the moment they got their STC.  I was looking forward to running it in my engine, and was glad that there was finally a lead-free solution for our engines.

I attended George Braly’s seminars at Oshkosh over the years to hear and learn more.  At last year’s, he seemed to blame Mooney fuel leaks on Mooneys, the Mooney design, and Mooney owners.  He came across as a lawyer-turned-salesman who was using lawyerly obfuscation and deflection to shift blame away from his product.  I left halfway through the seminar.

Needless to say, I’m no longer an advocate for G100UL.

[MikeOH]

5 hours ago, George Braly said:

There are about 150 aircraft that have used G100UL Avgas.   Of that number, there are 5 that have reported in-service issues that did not have clear evidence of prior leakage of 100LL.   

By my math, that's a 3.3% failure rate, or 33,000 ppm defect level.

Not sure what engineer/scientist/QA department would approve a product to ship with those numbers!

[MikeOH]

4 hours ago, EricJ said:

The more those guys talk that way the more I lose respect for both of them.   Likewise Scott Perdue.    It's pretty much gaslighting at this point, in my opinion.

I've never had much respect for Perdue, but always thought Braly did a great job of marketing science that had been known since Lindburgh's time and WWII, as his own but made sense from "a lawyer turned salesman!" point of view  So, good on him for GAMI... up until this G100UL fiasco!

OTOH, I've liked Mike Busch and his engine philosophy, but admit this 'softball interview' with Braly was a bit disappointing, unfortunately. Definitely felt like gaslighting and helpin' out a good ol' boy vibe.

[redbaron1982]

4 minutes ago, MikeOH said:

OTOH, I've liked Mike Busch and his engine philosophy, but admit this 'softball interview' with Braly was a bit disappointing, unfortunately. Definitely felt like gaslighting and helpin' out a good ol' boy vibe.

True. Up to this point my thinking was "Hey, Mike Busch doesn't want to get involved in this drama, I respect that". Now I am not so sure. Interviewing Braly without bringing up all the issues with G100UL is almost the same as endorsing G100UL.

[varlajo]

31 minutes ago, MikeOH said:

By my math, that's a 3.3% failure rate, or 33,000 ppm defect level.

Not sure what engineer/scientist/QA department would approve a product to ship with those numbers!

I am not necessarily buying the 150 aircraft number either. KWVI, a very busy GA airport where G100UL does not have a monopoly, reported just 13 (thirteen) G100UL sales transaction per month in late summer. How many aircraft would that be? Four? Five?