G100UL - fuel leak

[redbaron1982]

It looks like GAMI is acknowledging now that nitrile o-ring may swell if soaked in G100UL.

https://www.avweb.com/aviation-news/gami-says-all-high-aromatic-gasolines-are-hard-on-paint/

[gabez]

14 minutes ago, redbaron1982 said:

It looks like GAMI is acknowledging now that nitrile o-ring may swell if soaked in G100UL.

https://www.avweb.com/aviation-news/gami-says-all-high-aromatic-gasolines-are-hard-on-paint/

well the cat is our of the bag now. still nothing from my mechanic hopefully I get something late this week, beginning next

 

[MikeOH]

2 hours ago, wombat said:

My take-away from all of this is:

#1: Based on the independent testing shown in this video: https://youtu.be/sPeQ6T3vB2E the negative effects that the OP @gabez and @larryb are probably caused by the G100UL they used.  No testing was done to determine if this fuel was contaminated or if it met the manufacturer's specifications.

#2:  There are a lot of people that have very strong opinions about how much testing should be done prior to both making a new product available for use and making a new product a defacto requirement (such as prohibiting other options).

#3: There are a lot of people that have very strong opinions about how bad the TEL from avgas is for people in the quantities and concentrations created by piston GA use.

 

Personally, I'm disappointed that @George Braly's product seems to have this side effect and would love to hear back from him about this.   This makes me less excited about the fuel, but I would still be willing to use it.    I'm much happier knowing about the negative aspects than being unaware of them.

This not disappointment in George or in GAMI; I don't have any evidence to indicate anything other than someone trying their best to bring a product to market legally and safely.

I think that's a pretty decent summary of take-always.  And, agree, best to know about the negative aspects.  Which is why I maintain my position that we should not be forced to a single fuel solution until it is completely vetted in the field (years).

In regards to your last paragraph, would you have those same "someone trying their best" comments had one of Big Oil developed G100UL and these issues were now coming to light?

[wombat]

10 minutes ago, MikeOH said:

... would you have those same "someone trying their best" comments had one of Big Oil developed G100UL and these issues were now coming to light?

Probably not.

On the other hand, I would have expected Big Oil to have done significantly more testing and be less open about what testing they did.

[MikeOH]

49 minutes ago, wombat said:

Probably not.

On the other hand, I would have expected Big Oil to have done significantly more testing and be less open about what testing they did.

Thanks for your honest answer!

I have no inherent animus towards George or Big Oil; they are BOTH out to make a PROFIT.  I attempt to be objective regardless of who is providing a new product; either could be honest, or not, open with downsides, or not.  All should be held to the same standards.

I have no reason to believe one or the other is more likely to be 'less open'

[Larry]

In some municipalities, homes near the airports are old enough to have been painted with paint containing lead.  Does the testing for lead take this under consideration?

[Shadrach]

23 hours ago, FlyingDude said:

I asked chatgpt to calculate the expansion of 360 liters (90 gallon) of avgas from 0* Celsius while receiving 2kW power which would be the full sun load on 2 m2 surface area which is oversized for the above wing surface at 45th parallel and assumes full absorption, which means the wings are pitch black.  16mL per second. That's pretty nothing for the fuel vents to drain.

 

Maybe it is due to the configuration of the three bay, 64 gal tanks, but I can say that I have never seen them leak fuel from the vents. 

[Shiroyuki]

7 hours ago, redbaron1982 said:

It looks like GAMI is acknowledging now that nitrile o-ring may swell if soaked in G100UL.

https://www.avweb.com/aviation-news/gami-says-all-high-aromatic-gasolines-are-hard-on-paint/

This is completely unacceptable response from GAMI.

In summary:

Yes we know our fuel is hard on paint, but 100LL is also hard on paint.

Yes we know O-ring will swell, but it still work fine.

I call these bullshit. We have issue with this fuel because it is way more harsh on paint to a point it strips the paint in 48 hours, and regarding the o-ring, you can't convince me a 10% larger diameter will work fine.

And what about the ultimate question? If this fuel is so harsh on everything, what is it going to do with PRC or tank sealant? If it eat tank sealant like paint or nitrile, no way in a million light year i would touch this fuel ever. There's no way to fix that!

I hope no one is going to find out that o-ring issue the hard way. Maybe one day someone got a small leak on a fuel line going to the engine, then dripped onto muffler... That would put an end to G100UL.

[Shiroyuki]

Just spent some time reading swift fuel's website and it mentioned:

"This is because G100UL contains an aromatic amine “meta-toluidine” – an aggressive solvent that smells like turpentine – that testing shows is particularly prone to damaging paint/coatings, sealants, bladders, diaphragms, and various elastomeric parts in aircraft fuels systems."

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"Due to liability concerns, Swift Fuels avgas products may not be intermixed with G100UL which contains 3% – 4.5% m-toluidine (an aggressive solvent). Such solvents as found in G100UL (aka “aromatic amines”) are known to disturb certain aircraft fuel system elastomers, sealants, and anti-corrosive coatings."

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"Aromatic amines are very aggressive solvents that tend to disturb fuel-wetted aircraft fuel system components

Swift Fuels conducted extensive testing on aromatic amines between 2012 and 2022 and publicly announced our decision not to utilize aromatic amines as octane boosters in commercially available avgas.

Swift Fuels experience has been that aromatic amines can disturb aircraft fuel bladders, anti-corrosion coatings, sealants, epoxy coatings, servos, elastomers, hoses, aircraft fabric, and other critical components leading to flight safety issues.

Aromatic amines are also heavy and tend to freeze well above -58°C, thus requiring special blending with heavy aromatics. This can change the weight/balance of the aircraft. It can also trigger fuel maldistribution in certain carbureted engines."

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So I suppose they are not wrong...

[Fly Boomer]

Ran across this article discussing the effect car gas can have on your car paint.  Car gas, as you know, is lower octane, can contain a percentage of (benign) alcohol, and likely has a lower percentages of aromatics.  Aircraft paint, as you know, is tougher than car paint because it has to stand up to abuses not experienced on our roads.  Anyway, the assertion is that car gas can stain your paint or, with enough exposure, can strip your paint.  Who knew?

https://paintloving.com/does-gas-ruin-car-paint/
 

[GeeBee]

Not just KRHV, Centennial in Arapahoe, CO and most recently KVNY have come under the lead gun. Look, we can argue about the validity of the studies, the numbers etc all we want, and it matters little. Like the drone scares in NJ, once the public is stampeded, you better have a plan to GTFOOTW.

[MikeOH]

12 minutes ago, GeeBee said:

Not just KRHV, Centennial in Arapahoe, CO and most recently KVNY have come under the lead gun. Look, we can argue about the validity of the studies, the numbers etc all we want, and it matters little. Like the drone scares in NJ, once the public is stampeded, you better have a plan to GTFOOTW.

WOW!  Now you're resorting to vulgarity rather than logic?

The validity of these 'studies' needs to be challenged in court.

Bizarre analogy with 'drone scare' but, maybe, the same outcome...the drone scare is already fading and will be in the news cycle rear-view mirror shortly.  If G100UL doesn't work out, and there are no other alternatives, then this, too, will fade until another contender appears.  GA isn't going to get 'shut down' over this.

[exM20K]

1 hour ago, GeeBee said:

Not just KRHV, Centennial in Arapahoe, CO and most recently KVNY have come under the lead gun. Look, we can argue about the validity of the studies, the numbers etc all we want, and it matters little. Like the drone scares in NJ, once the public is stampeded, you better have a plan to GTFOOTW.

I agree with the emotional stampede but strongly disagree with getting out of the way.

One cannot reason someone out of a position they have been driven in a panic into. One can only work within the political and legal system to win.

I’m deeply involved in one of the great and current civil rights policy debates, and I used to engage with the other side in describing how the existing laws function in legal commerce. No more.  We now fight in court, where we win with the facts and reason. And we win.

I am far from fluent on environmental law and the regulatory state, but the 100LL thing will ultimately be decided there. I hope Million Dollar Mark has his experts queued up to push back against preposterous “studies” showing abnormal and elevated lead levels in children residing near GA airports, but I fear he hasn’t.
 

If the AOPA’s leadership wishes to stop the bleeding of membership and re-establish its relevance to grassroots GA, it has a window here to take an aggressive stand against the emotional tidal wave by side-stepping into the legal realm to protect our ability to fly. Else they will feed off the corpse of a once-great association while somebody else carries the fight.

Don’t fold.

-dan

[GeeBee]

Here is your fight and the cause of the stampede. You really think you or AOPA can overcome this kind of science? Carry on Don Quixote:

"Protecting children from exposure to lead is important to lifelong good health. No safe BLL in children has been identified. Even low levels of lead in blood have been shown to have effect. Low levels of lead can reduce a child's learning capacity, ability to pay attention, and academic achievement.

Some effects of exposure to lead can be permanent. If caught early, however, parents, healthcare providers, and communities can take actions to prevent further exposure. The most important step that anyone can take is to prevent lead exposure before it occurs."

https://www.cdc.gov/lead-prevention/php/news-features/updates-blood-lead-reference-value.html

 

"Currently, the source
category with the greatest contribution to total U.S.
air emissions [ed: of lead] is piston-engine aircraft operating on
leaded fuel (EPA, 2018d; Task Force, 2016). "

 

https://www.epa.gov/sites/default/files/2018-12/documents/fedactionplan_lead_final.pdf