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

[gabez]

it would be interesting to know if the plane in the PAFI had a leak prior to using the candidate fuel. I mean why would you use a leaking plane

 

[philiplane]

10 hours ago, redbaron1982 said:

That's odd. If that were from 100LL, I would expect to see some blue staining, but instead, there is some brown residue.

It is disturbing that the same photos are in the PAFI document of Lessons Learned.

Providing the source of these pictures could help clear up the confusion.

100LL also leaves a dark brown residue from extended seepage.

[philiplane]

12 hours ago, gabez said:

where was that disclosed by GAMI? 

What's to "disclose"? Aviation fuels use various blends of distillates, and solvents like toluene and xylene. Both of these solvents soften paint. 

[gabez]

6 minutes ago, philiplane said:

What's to "disclose"? Aviation fuels use various blends of distillates, and solvents like toluene and xylene. Both of these solvents soften paint. 

you stated "Since it has more solvent action than 100LL"....the question is not if aviation fuel has solvents, I am asking about your statement. where did you find that and/or where was that disclosed? 

[philiplane]

6 minutes ago, gabez said:

you stated "Since it has more solvent action than 100LL"....the question is not if aviation fuel has solvents, I am asking about your statement. where did you find that and/or where was that disclosed? 

The MSDS sheets for G100UL and for 100LL avgas list the components of each, and the percentage ranges of each component. It's not a secret. Nor is it a secret that toluene or xylene soften paint. You can buy them at any hardware store for the express purpose of thinning enamel paints. 

Fuel tanks aren't supposed to leak. But if they do, blaming the fuel for then stripping the paint is not the answer. Fixing the leak is the answer. 

[EricJ]

28 minutes ago, philiplane said:

Fuel tanks aren't supposed to leak. But if they do, blaming the fuel for then stripping the paint is not the answer. Fixing the leak is the answer. 

If fuel has historically never stripped your paint, and a new fuel is represented as being essentially a drop-in for the old fuel, but it does strip your paint, I don't think the leaks are the issue.    Tanks will develop leaks, whether they have bladders or wet wings or integral tanks or whatever, and if the new way of finding a leak is that that paint gets stripped off, I think that's a highly undesirable feature of the fuel.

 

[gabez]

2 hours ago, EricJ said:

If fuel has historically never stripped your paint, and a new fuel is represented as being essentially a drop-in for the old fuel, but it does strip your paint, I don't think the leaks are the issue.    Tanks will develop leaks, whether they have bladders or wet wings or integral tanks or whatever, and if the new way of finding a leak is that that paint gets stripped off, I think that's a highly undesirable feature of the fuel.

 

I agree with you. Either it is drop in and it works with all vintages or it is not and guardrails will need to be put in place. 

[George Braly]

17 hours ago, mluvara said:

Are you saying that the photos in the PAFI lessons learned (page 7) are misleading and not from a candidate fuel, but from 100LL?

 

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

Mike, 

I am aware where those photos came from.  I have been double checking and trying to verify from some contacts in PAFI / EAGLE that those pictures are from 100LL.   As a side matter - - PAFI / EAGLE has been less than "transparent" about a lot of their data.   Also, there are not and have not been any fuels in the PAFI program with significant aromatics that have been tested by PAFI / EAGLE. 

However, based on my understanding of the various aircraft that were tested and that used those various test fuels I have reason to believe this airplane make/model was not one of the PAFI test planes.  I think the PAFI / EAGLE folks may have used this as a convenient example.    

In any event, there are other similar pictures available that demonstrate similar appearances that were documented from years ago before PAFI/EAGLE ever came into existence.  When I run across those, I will try to post those up, also.    

[Marc_B]

6 hours ago, George Braly said:

I am aware where those photos came from.  I have been double checking and trying to verify from some contacts in PAFI / EAGLE that those pictures are from 100LL. 

@George Braly you're aware they are pictures from PAFI lessons learned document, or you're aware of what aircraft and fuel it was running? 

[PT20J]

27 minutes ago, Marc_B said:

@George Braly you're aware they are pictures from PAFI lessons learned document, or you're aware of what aircraft and fuel it was running? 

I believe he answered that in his post. 

[Schllc]

Mr Braley posted his personal cell phone number in this thread, and offered to speak to me.  I took him on his offer.  
He answered my call today and spoke to me very candidly and cordially for a little more than 30 minutes, and would have spoken longer I am sure.  I got my questions answered, some food for thought, and understand he is a busy man and wanted to respect his time.  
My description of the the conversation was this…
He was well informed, direct, and willing to discuss anything openly and honestly. 
He will talk to anyone who wants to have a civil conversation, and while ours didn’t get close to anything else, I certainly got the sense from the man that he would engage that way to a point as well if requested. 
Overall, I would say if you really are curious about this situation, and want to get the answers directly from the source, or at least really listen to the other side of the story, he will likely take your call and share what he knows. 

[Marc_B]

2 hours ago, PT20J said:

I believe he answered that in his post. 

Sort of, but not entirely.  What I mean, is that I think an assumption was made that the pictures in the PAFI lessons learned "must" have been 100LL as it was felt that PAFI did not have a high aromatic fuel.  BUT, that doesn't mean that the picture was 100LL or even a high aromatic fuel for that matter.  I was just asking if Mr. Braly knew what airplane this was and what fuel it was running if he cited this.  It was my understanding that many fuels (Bertorelli mentioned in video below) were tested leading up to the candidate fuels in the PAFI program which may or may not have contributed to the PAFI lessons learned.  I have no clue where the pictures in the PAFI lessons learned came from, but I'd hope that Mr. Braly did if he was citing these as examples.

Sounds like Mr. Braly was checking references to find out if his assumption was correct. 

 

[ragedracer1977]

On 1/26/2025 at 5:22 PM, George Braly said:

Marc,

I wish I had the band-width to jump into this with more time and data.   

However, claims that 100LL does not damage paint - - are contrary to lots of observations from the field.

Let me try to verify the source of the fuel in that photograph - - in the mean time, I deleted it from the post.  

I apologize for any confusion.

Let me try to get better data.

In the mean time, I have to (get to) go fly a new experimental turbo system!   

George 

 

George, 

i see you updated this to verify. Good to hear!

 I’m a relatively blunt person, as you are.  Sometimes that comes off as rude.  Sorry if I come off that way. 

 I do have to ask - you say this is one of countless examples of 100LL paint damage.  I think of myself as pretty good at internet research… I’ve honestly spent several hours searching in every fashion I know. I cannot find even a [i]single[/i] example photo of paint damage caused by a 100LL fuel leak. 

My Google-fu may be weak.  Can you provide some examples?

All that google stuff did lead me to a couple of additional questions.

100LL is bad for tires. Even a small leak can pretty seriously damage the rubber.  Is the effect any different with G100UL? What about hydraulic brake lines in the area?

 Another concern I thought about pertains to my own plane.  One of the most hazardous systems in twin Cessna’s is the heater. It runs on 100LL.  Have you tested any janitrol/southwind type combustion heaters? Is the “free-air” (my non expert description!) combustion of G100UL similar to 100LL? The fuel lines for the heater, in the nose, are partially neoprene rubber. (S51-4 hose).  Will they play well with the high aromatic content?
By nature, they run very rich. Any issues with deposits, etc?
 

 

[Pinecone]

On 1/17/2025 at 9:35 PM, Justin Schmidt said:

Are we forgetting that auto manufacturers are still saying 6000 miles or 3 months

My 2012 Fiat is 1 year or 8000 miles.

My 2002 BMW is variable, but starts at 15,525 miles or 1 year.  BMW in the 90s used a complex algorithm that took into account miles, RPM, cold starts, etc.  They found that the fuel burned gave them almost the same results.  So for my 2002 M3, IIRC, it is 600 gallons of fuel burned between changes.  Drive sedately and you can go over 15,525 miles.  Drive hard and you can get the system to request a change as short as 5000 miles (one crazy guy that believed that red line was the perfect RPM for all operations).

 

[Pinecone]

On 1/18/2025 at 8:36 AM, A64Pilot said:

Milage is not really a very accurate way to schedule oil life, but it was forever the only thing available, hours is better, but even more accurate is the amount of fuel used, fuel use rate being a good metric to determine how hard the engine was being run.

 

That is what BMW went to in the early 2000s.

[Pinecone]

On 1/18/2025 at 11:35 AM, gabez said:

Quick update: I was able to see my plane, the tanks, videos of the borescope of the cylinders. I was also able to see the cylinder, piston and push rod of the Grumman that nuked at Hollister. Because it's an active FAA investigation I am told to wait to post pics/videos until the FAA makes their decision as this is with DC now. Investigators came took pics, samples and actually put G100UL back into my plane and run it to collect oil sample...oof. To GAMI's defense they can't access samples either as per FAA request. 

The leaks are coming from the copilot aux tank, outboard seam and inboard seam. Also from 3 screws from an access panel on the pilot side main. The sealant is original from when Mooney built the aircraft and when the Aux tank were installed. On the outboard side it seems the fuel drains off the tank from a drain hole. Again, this aircraft did not have leaks and the magnitude of the current leak is pretty vast. I would have had blue stains of the same magnitude. Plane just completed annual in November we would have seen this if it was there. 

I used about 80 gallons of G100UL, 30 gallons, 30 gallons, 20 gallons, give or take:

Refuel/Flight 1: 15 gallons in the Laux, 15 gallons in Raux, main(s) had about 20 gallons each of 100LL

Refuel/Flight 2: 15 gallons in the Laux, 15 gallons in Raux, main(s) had a mix of 100LL/G100UL

Refuel/Flight 3: 10 gallons in the Laux, 10 gallons in Raux, main(s) had a mostly if not all G100UL 

So the aux saw most of the G100UL and the main only at the very tail end. The RV and Grumman had the G100UL for several weeks before the former realized fuel on the floor and the Grumman 

Repairs have started already. I am also told some aircraft that had purchased G100UL, have now pulled the fuel out of their tanks so I don't believe many are purchasing the fuel (the latter is just my hypothesis). 

Additionally, the paint peeled from the inside out like it exploded I think pouring fuel over the paint does not reflect the dynamic of what is happening. Independently from any lab tests, what we are experiencing is as simple as, the tests performed were not representative of real world conditions and that is to nobody's fault, it happens with car manufacturers all the time, GAMI needs to step in now and make it right financially. 

Also, I keep hearing of testing about paint and O rings (which is great) but any testing on sealant? I agree with GAMI fuel belongs in the tanks....we can't keep it there tho so I want to see what testing what done on the tank sealant. 

 

More to come...

When you say you fueled the aux tank, what aux tanks do you have?  If you have the typical Mooney Monroy extended tanks, they are not separate tanks, they extend the existing tanks.

The picture of your pain looks like that of the You Tube video, which, TO ME, appears to be a primer failure.

[Pinecone]

On 1/18/2025 at 10:16 AM, Schllc said:

My uncle, in the early 80’s, participated in a synthetic oil change study where he sent samples of his oil every 1000 miles for analysis. He did this for three years. 

There used to be a web site of a guy that was seeing how long he could run an engine without changing the oil at all.  He did change the filter at the recommended interval and then topped up the oil removed with the filter.  He did Blackstone oil analysis at each filter change. 

IIRC he was well over 300,000 miles.

[Pinecone]

On 1/21/2025 at 9:03 PM, GeeBee said:

That is my suspicion too.

Mine also.  I have said so since the video first came out.

[Pinecone]

On 1/26/2025 at 5:44 PM, gabez said:

what's your point? Tanks leak yes. do all our tanks decided to start leaking within a week of using G100UL? I doubt it.

To be accurate, not ALL fuel tanks start leaking within a week of using G100UL.

[mluvara]

21 hours ago, George Braly said:

Mike, 

I am aware where those photos came from.  I have been double checking and trying to verify from some contacts in PAFI / EAGLE that those pictures are from 100LL.   As a side matter - - PAFI / EAGLE has been less than "transparent" about a lot of their data.   Also, there are not and have not been any fuels in the PAFI program with significant aromatics that have been tested by PAFI / EAGLE. 

However, based on my understanding of the various aircraft that were tested and that used those various test fuels I have reason to believe this airplane make/model was not one of the PAFI test planes.  I think the PAFI / EAGLE folks may have used this as a convenient example.    

In any event, there are other similar pictures available that demonstrate similar appearances that were documented from years ago before PAFI/EAGLE ever came into existence.  When I run across those, I will try to post those up, also.    

"Tu Quoque, 100LL?"

I clarified with the FAA. See below.

How about we try not to distract from the discussion of G100UL effects? We know the experience of 100LL.

 

[gabez]

1 hour ago, Pinecone said:

To be accurate, not ALL fuel tanks start leaking within a week of using G100UL.

how do you know? who has wet tanks and currently using G100UL? 

we do have 7 aircrafts with reported problems after introducing G100

Edited Tuesday at 05:19 PM by gabez

[philiplane]

Here is wrinkled paint on the fuel tank vent on a 2015 Cirrus, which has never seen G100UL. This is a well-cured urethane paint that has never been refinished since new.

The wrinkles are caused by 100LL. And there is rarely any liquid here, only if you overfill the tank and the plane is on a slope.