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

[Sabremech]

12 minutes ago, GeeBee said:

Uh I believe you are putting words in my mouth. I doubt any fuel would be as aggressive as Skydrol since fuel is not di-ester based. However a new fuel may necessitate some higher level of maintenance, just as boat owner had to do with added ethanol. I had to replace all my fuel lines for instance. I do believe in nice and tight fuel systems. which is why I resealed my tanks even though the weeping was in the "permissible" zone. I know there is "permissible" tank leakage, but I'm not a fan of flying a giant Van Der Graff generator seeping fuel. Call me crazy. It may be very likely you will have to reseal your tanks and replace a few o-rings to accept the new fuel, just like you had to get a transponder, then an encoder, then ADS-B and if you are Canadian, a diversity set up. Things change and sometimes you have to spend money if you want to keep flying the plane of your choice.

Why should we have to accept this additional maintenance and cost to run a different fuel? None of this is cheap! it sure seems that the mission continues to make flying only possible for the wealthy! Why not design and manufacture a fuel that is a direct drop in replacement that does NOT require additional maintenance and cost to any owner? That should be the priority to not add additional cost going forward! If the new fuel costs a little more per gallon to get it out in the field, that’s understandable. To require me to reseal my poorly maintained 50 + year old tanks because those schmuck mechanics over the years couldn’t do it right is ridiculous. Stop blaming mechanics for this mess. Stop blaming mechanics for not adhering to some obscure letter from the FAA that says we should be replacing o-rings with Viton or Flourosilicone every chance we get. This mess isn’t on us and it shouldn’t be. There’s problems with this fuel for the guy on a budget. Those who don’t have a budget could care less and are over zealous fans of this product because it doesn’t impact their wallet like it does most of us little guys who just want to enjoy the same freedom of flying. @George Braly, good job on making an effort and progress on your unleaded fuel but please stop discounting the little guy on a budget. Paint stains or paint loss matter to us! Don’t brush us off like AOPA does. 

[PT20J]

Can we pleeease stop discussing Skydrol. Everyone agrees on two things: 1) it's nasty stuff, and 2) it's not used in Mooneys.

I would still like to figure out how to resolve the discrepancy between the two tests with one showing no affect on paint and the other showing severe paint damage. 

The discussion about o-rings got me wondering how long nitrile o-rings last in service. As near as I can find out, no one knows because there are too many variables. SAE AS5316 sets the shelf life for aerospace applications at 15 years. But I found a paper that suggests 7 would be more appropriate. https://www.sciencedirect.com/science/article/abs/pii/S0141391022003779

So, let's say 35 years ago the factory installed an o-ring that had been stored for 5 years. That means that the o-ring is 40 years old. Now suppose the fuel is switched to G100UL and sometime later the o-ring starts to leak. How can we know that that old/tired o-ring would not have leaked if it had remained on 100LL? I'm not arguing one way or the other, but merely pointing out that nitrile o-rings are life limited parts and perhaps they don't get replaced as often as they should. 

Edited January 8 by PT20J
Corrected to indicate that nitrile o-rings are life limited. Fluorosilicone and Viton have unlimited shelf life.

[George Braly]

22 minutes ago, PT20J said:

Can we pleeease stop discussing Skydrol. Everyone agrees on two things: 1) it's nasty stuff, and 2) it's not used in Mooneys.

I would still like to figure out how to resolve the discrepancy between the two tests with one showing no affect on paint and the other showing severe paint damage. 

The discussion about o-rings got me wondering how long nitrile o-rings last in service. As near as I can find out, no one knows because there are too many variables. SAE AS5316 sets the shelf life for aerospace applications at 15 years. But I found a paper that suggests 7 would be more appropriate. https://www.sciencedirect.com/science/article/abs/pii/S0141391022003779

So, let's say 35 years ago the factory installed an o-ring that had been stored for 5 years. That means that the o-ring is 40 years old. Now suppose the fuel is switched to G100UL and sometime later the o-ring starts to leak. How can we know that that old/tired o-ring would not have leaked if it had remained on 100LL? I'm not arguing one way or the other, but merely pointing out that nitrile o-rings are life limited parts and perhaps they don't get replaced as often as they should. 

 

Not only are nitrile  / buna N parts generally "life limited" - -  if they are in a Bendix fuel unit - - there is supposed to be an expiration date sticker on the unit that alerts the mechanic that the unit must be overhauled before the aircraft can be returned to service.    

If, and only if, the unit is fully serviced and ALL of the nitrile seals are replaced with fluorosilicone - -  can the life limit sticker be removed from the unit. 

[Sabremech]

3 minutes ago, George Braly said:

 

Not only are nitrile  / buna N parts generally "life limited" - -  if they are in a Bendix fuel unit - - there is supposed to be an expiration date sticker on the unit that alerts the mechanic that the unit must be overhauled before the aircraft can be returned to service.    

If, and only if, the unit is fully serviced and ALL of the nitrile seals are replaced with fluorosilicone - -  can the life limit sticker be removed from the unit. 

Unless it’s a flight school aircraft, there is no requirement to have it overhauled. Nor can I force an owner to have it overhauled as a mechanic. 
Where are you coming up with this stuff? 

[George Braly]

Please educate me:

Private responses are fine:  gwbraly@gami.com

For those of you that are concerned about fuel leakage and possible paint damage,  please let me know the following:

1)   Year / Make Model;  (Optional N number)

2)   Year when last painted.

3)  Type of paint when last painted, if known.

4) Is your wing currently "weeping" or otherwise exhibiting any indication fuel leakage ?  (Photographs would be helpful.)

 

[George Braly]

1 minute ago, Sabremech said:

Unless it’s a flight school aircraft, there is no requirement to have it overhauled. Nor can I force an owner to have it overhauled as a mechanic. 
 

Sabre,

You may be right on the regulatory issue.  I have not researched that. 

But what you stated explicitly contradicts the Bendix document.     

And - - regardless of whether or not your regulatory interpretation is correct:

Failing to comply with that 1980 Service Bulletin - -  absent a LOT of explicit log book documentation and warnings to the owner(s) of the aircraft - - the failure to comply with a  SB relating to the fuel system - - would likely subject the mechanic to some serious liability in the event the fuel servo failed and resulted in an accident. 

George

[Sabremech]

1 minute ago, George Braly said:

Sabre,

You may be right on the regulatory issue.  I have not researched that. 

But what you stated explicitly contradicts the Bendix document.     

And - - regardless of whether or not your regulatory interpretation is correct:

Failing to comply with that 1980 Service Bulletin - -  absent a LOT of explicit log book documentation and warnings to the owner(s) of the aircraft - - the failure to comply with a  SB relating to the fuel system - - would likely subject the mechanic to some serious liability in the event the fuel servo failed and resulted in an accident. 

George

Again, we are not required to force the owners to comply with any S/B or overhaul requirements. Unless the aircraft is a flight school aircraft, the requirement you state does not apply and can not be forced. The liability is on the owner and not the mechanic unless we worked on the servo. Then we are liable for the work we did and not the whole servo. 

[EricJ]

13 minutes ago, George Braly said:

Sabre,

You may be right on the regulatory issue.  I have not researched that. 

But what you stated explicitly contradicts the Bendix document.     

And - - regardless of whether or not your regulatory interpretation is correct:

Failing to comply with that 1980 Service Bulletin - -  absent a LOT of explicit log book documentation and warnings to the owner(s) of the aircraft - - the failure to comply with a  SB relating to the fuel system - - would likely subject the mechanic to some serious liability in the event the fuel servo failed and resulted in an accident. 

George

It doesn't.    You seem to be unaware of how maintenance is done in GA for privately owned aircraft, and this seems to color your reponses to the impractical side and discounts the risk to the affected fleet of using fuel that potentially impairs material performance.   I find this seeming disregard for the safety of the affected fleet disturbing.

[GeeBee]

1 hour ago, Sabremech said:

Why should we have to accept this additional maintenance and cost to run a different fuel? None of this is cheap! it sure seems that the mission continues to make flying only possible for the wealthy! Why not design and manufacture a fuel that is a direct drop in replacement that does NOT require additional maintenance and cost to any owner? That should be the priority to not add additional cost going forward!

Because it is likely you "can't get there from here". As I said before, it is unlikely there will not be some magic elixir that will work perfectly without some changes to our aircraft and the way we operate and some of that will cost money. As I see it, G100UL is the most "minimally invasive option" out of a basket of bad options. 

I would like to have a perfect "drop in" option that would cost me no money, or changes but then I learned those centerfolds are airbrushed.

"You can't always get what you want, but you get what you need".--Mick Jagger 

[Sabremech]

13 minutes ago, GeeBee said:

Because it is likely you "can't get there from here". As I said before, it is unlikely there will not be some magic elixir that will work perfectly without some changes to our aircraft and the way we operate and some of that will cost money. As I see it, G100UL is the most "minimally invasive option" out of a basket of bad options. 

I would like to have a perfect "drop in" option that would cost me no money, or changes but then I learned those centerfolds are airbrushed.

"You can't always get what you want, but you get what you need".--Mick Jagger 

It’s early in the game. Other companies are working on a fuel as well. You could temper your bias a bit. Are you a silent investor? Might explain your over exuberance. 

[MikeOH]

2 hours ago, Justin Schmidt said:

Please share the actual scientific/engineering data that g100ul causes problems.

GAMI has admitted O-rings swell, and staining can occur.  Do you need me to post fuel prices to prove G100UL is more expensive?

[GeeBee]

19 minutes ago, Sabremech said:

It’s early in the game. Other companies are working on a fuel as well. You could temper your bias a bit. Are you a silent investor? Might explain your over exuberance. 

I am not an investor, but I wish I was. I have been watching this for a long time and I don't see Swift who is the closest competitor as being able to be used fleet wide. Too narrow detonation margin. Heck they even lost the UND fleet with their 94UL and their 100R is supposed to work? As of right now 100R is usable in only C-172 with lower compression engines. The others have suggested de-rating engines. That is not going to work. For starters, how do you modify the performance data in the AFM's especially of airplanes and manufacturers out of business like Mooney? G100UL has so much margin the warbird guys are able to run with the ignition un-retarded. If I remember correctly, Mr. Braly was running an TIO-550 at over 400 hp in the test cell with no detonation.

[MikeOH]

@George Braly

Why have you not answered what material the seals and O-rings in the test Cirrus and Embry-Riddle 172 were made out of?  That is important data to know when you post that there have been no issues with those aircrafts' fuel systems.

[Aaviationist]

7 minutes ago, MikeOH said:

@George Braly

Why have you not answered what material the seals and O-rings in the test Cirrus and Embry-Riddle 172 were made out of?  That is important data to know when you post that there have been no issues with those aircrafts' fuel systems.

I’m not sure why he responds to you at all. You have been nothing but completely unreasonable and combative. We get it. You aren’t going to use it. Why do you also need to act like a spoiled child?
 

what specifically is it you want?  Both in fuel and in this conversation. 
 

 

Edited January 9 by Aaviationist

[Sabremech]

13 minutes ago, GeeBee said:

I am not an investor, but I wish I was. I have been watching this for a long time and I don't see Swift who is the closest competitor as being able to be used fleet wide. Too narrow detonation margin. Heck they even lost the UND fleet with their 94UL and their 100R is supposed to work? As of right now 100R is usable in only C-172 with lower compression engines. The others have suggested de-rating engines. That is not going to work. For starters, how do you modify the performance data in the AFM's especially of airplanes and manufacturers out of business like Mooney? G100UL has so much margin the warbird guys are able to run with the ignition un-retarded. If I remember correctly, Mr. Braly was running an TIO-550 at over 400 hp in the test cell with no detonation.

There’s more companies working on this so hold your excitement. There’s Shell with their 100VLL, LyondellBasell/VP Racing working through the PAFI/ EAGLE process and doing well along with Swift fuels. Hopefully we’ll have some choices in the near future. 

[MikeOH]

19 minutes ago, Aaviationist said:

I’m not sure why he responds to you at all. You have been nothing but completely unreasonable and combative. 
 

what specifically is it you want?  Both in fuel and in this conversation. 

I've been logical in my arguments but refuse to 'disappear' just because you don't like what I say.  Rather than attack me personally, why don't you debate my points, one by one?  Maybe you can't?

I want to continue to make other, perhaps silent, Mooney owners think about the DOWNSIDES of G100UL, or any other unleaded fuel that becomes available, compared to 100LL which has worked fine.  I would like a fuel that is as close as possible to the performance of 100LL at a price that is as close as possible.  While I realize that is likely NOT going to happen, the mindset that we should just accept G100UL with its limitation WITHOUT complaint is ridiculous.  Kalifornia may be a lost cause but educating others in other states may prevent a runaway Federal mandate to use a single source fuel with, possibly, significant long term issues.  That approach seems a prudent method to work a new fuel into the GA fleet.  Why that bothers you so much is a mystery to me.

[Justin Schmidt]

16 minutes ago, MikeOH said:

GAMI has admitted O-rings swell, and staining can occur.  Do you need me to post fuel prices to prove G100UL is more expensive?

Many things do swell O-rings and there are allowances, that has been discussed. Staining of the paint can occur with many aviation products, I have 100ll blue stain by the cap when line guy didn't secure it correctly after a top off.

Frankly, not concerned about a few cents increase. Economies of scale is a real thing and if you are quibbling over a few pennies or even a dollar, perhaps aircraft ownership is not for you. Fuel of all types is a massively variable economy most of which we have no control over.

I'm more concerned about a group of you all operating under anonymity impugn the character and integrity of someone and a company without any controlled data.

There is zero evidence that g100ul causes any damage. In engineering you get the data before opening your mouth else one would be in a court room facing a libel lawsuit or even criminal. Evidence must be controlled and proper process else it isn't valid.

Now if one proves GAMI isn't working with someone that had an issue, that would be an issue. And until there is scientific, engineering data that says something, everyone should really shut up, keep it as something happened we are working on finding out the cause. Root cause analysis.

[GeeBee]

17 minutes ago, MikeOH said:

I've been logical in my arguments but refuse to 'disappear' just because you don't like what I say.  Rather than attack me personally, why don't you debate my points, one by one?  Maybe you can't?

I want to continue to make other, perhaps silent, Mooney owners think about the DOWNSIDES of G100UL, or any other unleaded fuel that becomes available, compared to 100LL which has worked fine.  I would like a fuel that is as close as possible to the performance of 100LL at a price that is as close as possible.  While I realize that is likely NOT going to happen, the mindset that we should just accept G100UL with its limitation WITHOUT complaint is ridiculous.  Kalifornia may be a lost cause but educating others in other states may prevent a runaway Federal mandate to use a single source fuel with, possibly, significant long term issues.  That approach seems a prudent method to work a new fuel into the GA fleet.  Why that bothers you so much is a mystery to me.

Did you know those centerfolds are airbrushed?

[PT20J]

1 hour ago, George Braly said:

 

Not only are nitrile  / buna N parts generally "life limited" - -  if they are in a Bendix fuel unit - - there is supposed to be an expiration date sticker on the unit that alerts the mechanic that the unit must be overhauled before the aircraft can be returned to service.    

If, and only if, the unit is fully serviced and ALL of the nitrile seals are replaced with fluorosilicone - -  can the life limit sticker be removed from the unit. 

The RSA fuel servos originally used Buna-N rubber parts and a cure date decal was affixed to the servo. Back in 1980, Bendix switched to flourosilicone parts and issued a service bulletin. 

RS-76-Rev1.pdf

[Aaviationist]

27 minutes ago, MikeOH said:

I've been logical in my arguments but refuse to 'disappear' just because you don't like what I say.  Rather than attack me personally, why don't you debate my points, one by one?  Maybe you can't?

I want to continue to make other, perhaps silent, Mooney owners think about the DOWNSIDES of G100UL, or any other unleaded fuel that becomes available, compared to 100LL which has worked fine.  I would like a fuel that is as close as possible to the performance of 100LL at a price that is as close as possible.  While I realize that is likely NOT going to happen, the mindset that we should just accept G100UL with its limitation WITHOUT complaint is ridiculous.  Kalifornia may be a lost cause but educating others in other states may prevent a runaway Federal mandate to use a single source fuel with, possibly, significant long term issues.  That approach seems a prudent method to work a new fuel into the GA fleet.  Why that bothers you so much is a mystery to me.

You’ve said the same thing. Nearly a dozen times. Your points have been debated over and over again and now you just whine like a child. 
 

Don’t use the fuel. Nobody cares. You aren’t educating anybody about anything.  You’re in California, go get some of each fuel, paint a couple pieces of aluminum with a common paint, throw them in the fuel, and let us know what happens. 
 

You are basing your entire repetitive argument on a single anonymous video, which was then refuted. 
 

you aren’t making any logical sense, you aren’t adding anything to the conversation, and quite frankly, you’re being a bully. 
 

alternatively, you can go formulate your own fuel. 

[Marc_B]

I think this is a discussion of risk and liability. So far we’ve only heard that this new fuel recipe is FAA approved. You can’t know what’s in it or how it varies from mix to mix. It may or may not cause issues with paint and elastomers and it hasn’t been in use long enough to prove itself one way or the other outside of a few case reports  

GAMI has pointed out poor wet wings/bladders and poor maintenance are the typical causes of leaks. GAMi has pointed out that 100LL and toluene are the usual cause of paint damage. GAMI has recommended viton o-rings and Teflon lined hoses but their test data with the FAA didn’t use this and it’s a “drop in fuel” fleet wide so no modification is necessary. So any modification is left to the PIC/owner and their mechanic for determining suitability.  Paint staining is known and requires “refueling hygiene” and is not considered to be damaging but rather known cosmetic issue due to fueling technique or leaks  

its ready to be used for those willing to use it. But the liability for any damage is assumed by the PIC/owner.  There’s been no admission of any harm or damage that wasn’t already in existence with 100LL.

it hasn’t been approved by Continental, Lycoming, Textron, Cirrus yet. But you can have approval from the FAA in the form of a STC that’s completed by your mechanic.  This is 100% legitimate and was proven to the FAA by years of testing.

Field testing and approval by the major companies will help improve individual comfort level with the product if this is shown to have good service record. Legislation is likely to escalate adoption. 
 

 

No need to argue points or discuss merits. Either use it or don’t. But those owners who are advocates, please use the alternative fuels to help speed knowledge and either prove a good track record or discredit it. This would be a big service to the GA community. 

[EricJ]

35 minutes ago, Justin Schmidt said:

There is zero evidence that g100ul causes any damage. In engineering you get the data before opening your mouth else one would be in a court room facing a libel lawsuit or even criminal. Evidence must be controlled and proper process else it isn't valid.

Field data is always important and very seldom controlled.   Field experiments done reasonably by concerned practicioners can also be invaluable, since they may have timely access and insights that might otherwise be overlooked.   I was an R&D engineer for several decades.   BTDT.

History has shown that an engineer or company that ignores field data does so at their own peril.

35 minutes ago, Justin Schmidt said:

Now if one proves GAMI isn't working with someone that had an issue, that would be an issue. And until there is scientific, engineering data that says something, everyone should really shut up, keep it as something happened we are working on finding out the cause. Root cause analysis.

In aviation you should absolutely not shut up about safety concerns.

[GeeBee]

1 hour ago, Sabremech said:

There’s more companies working on this so hold your excitement. There’s Shell with their 100VLL, LyondellBasell/VP Racing working through the PAFI/ EAGLE process and doing well along with Swift fuels. Hopefully we’ll have some choices in the near future. 

I would suggest you read the article in Aviation Consumer, October 2024 "High-Octane Unleaded : Where Are We"

You will be surprised to find Lyondell/Basell cannot work in airplanes with big bore Continentals or Lycomings. Swift fuels UL100R will actually result in a range decrease of 7% because of lower BTU and they too say the big bore engines are likely not possible. Further it uses ETBE which is actually illegal in CA for self propelled vehicles. Finally ETBE is ethanol, great, if you want to corrode out your tanks and fuel system. I sooner replace O-rings and seal my tanks, while they are still un-corroded.  Shell has withdrawn.

[Justin Schmidt]

16 minutes ago, EricJ said:

Field data is always important and very seldom controlled. 

In engineering field data means diddly shit. Only used to initiate proper engineering process of troubleshooting, root cause and the such. The navy would have crucified us if we initiated anything as fact on the submarine based off of field data. The worst engineers I have ever encountered were those knee jerk, gut reaction, quick draw fools. They would say things like "I have seen it before", "in my day we just", "it works on mine", "this one time and place it did this".

I have, also, seen quick draw "solutions" from field data troubleshooting kill people do forgive me on being a legitimate engineer wanting actual data from legitimate sources and processes.

One should shut up about blaming someone, a company or product when there is nothing to support the accusations and while data is properly being collected. There is a legal term for it...libel. George is a hell a lot more patient than I would be.

For all you know the guy could have used paint stripper in an attempt to get a free tank seal or paint job.

 

[Paul Thomas]

Re-arguing the same point with no new information is taking away from the actual data presented by users (that includes the youTube video) and the manufacturer. We're getting to the point where people are arguing just to argue and throwing in red herring just hoping to score a point.

The people I want to hear from the most are G100UL users. I want to hear the good, the bad, and the ugly but it's getting drowned by the noise made from members on both side of the isle that just want to argue. I'd say a thread for field reports should be created, but I'd imagine it would get taken over by the same members.

I get it, both sides have dug in and are deeply passionate about their positions but the tone and quality of the arguments are disappointing. Let's keep it fun and educational.