G100UL unleaded avgas approved

Captain Sweet T said:
Anyone know the timeline on testing and possible go live?
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the company will work with the FAA to expand the approved model list (AML) of engines and airframes after a period of testing with the Lycoming-powered Cessnas. Braly reports that he has been in discussions with Embry-Riddle Aeronautical University about possibly using the university’s fleet of Cessna 172s as part of a controlled test, although that discussion is ongoing.
While the STCs represent a significant step in the long path toward the elimination of leaded avgas, it will be some time before G100UL might be available fleetwide, and then only if it proves itself in this large-scale test.

To answer your question. Many years.
 
Cap'n Jack said:
But not a very good one. Paint your house with lead oxide pigmented paint and let your children play in those rooms.
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So long as the lead stays in the resin matrix and the children don’t eat it, absolutely nothing happens. Same with asbestos.
Not saying any of it is a good thing but people get hyperbolic about things they don’t understand.
Not that your opinion is relevant. Been working and supervising the use of a large variety of industrial chemicals for 35 years. Not little beakers in a lab in a hood. You?
 
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For timeline, it might be a lot faster than most of you think.
First, note that the FAA has defined the list of additional tests required. This is often a long process to get the tests defined.
Second, all but a few of these tests have been completed already, but reports are pending. That means they did the work and have the data, just not written the report.
Third, there really are not that many material and engine combinations in the fleet. The FAA highly likely focus on material combinations (e.g. fuel bladders, wet wings, composite vs metal tanks) and engines most at risk of problems. E.g. turbo charged.
Four, I have previously read a comment from an engineer who works for a large refinery. They make 100LL, the annual production is a single day of production, and it shuts down the plant for two days after to clean and remove the TEL. Therefore it is always scheduled when they are going to shutdown for maintenance which is not always when the fuel is required. Which causes other problems, plus the dedicated tanks and equipment He previously said the day either PAFI succeeds or GAMI gets the STC the refinery will never make 100ll again.
Five, we have a tanker driver shortage that is not going away. G100UL by mostly going through pipelines will reduce tanker demand.

Tim

Sent from my HD1907 using Tapatalk
 
tspear said:
For timeline, it might be a lot faster than most of you think.
First, note that the FAA has defined the list of additional tests required. This is often a long process to get the tests defined.
Second, all but a few of these tests have been completed already, but reports are pending. That means they did the work and have the data, just not written the report.
Third, there really are not that many material and engine combinations in the fleet. The FAA highly likely focus on material combinations (e.g. fuel bladders, wet wings, composite vs metal tanks) and engines most at risk of problems. E.g. turbo charged.
Four, I have previously read a comment from an engineer who works for a large refinery. They make 100LL, the annual production is a single day of production, and it shuts down the plant for two days after to clean and remove the TEL. Therefore it is always scheduled when they are going to shutdown for maintenance which is not always when the fuel is required. Which causes other problems, plus the dedicated tanks and equipment He previously said the day either PAFI succeeds or GAMI gets the STC the refinery will never make 100ll again.
Five, we have a tanker driver shortage that is not going away. G100UL by mostly going through pipelines will reduce tanker demand.

Tim

Sent from my HD1907 using Tapatalk
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Add to that there is one global supplier of TEL. That plant stops making it for any reason, game over.
 
Hang 4 said:
Add to that there is one global supplier of TEL. That plant stops making it for any reason, game over.
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That has been a risk for a while. A number of years ago I recall the FAA actually put in place a mitigation plan to start production somewhere if the existing plant closes. No idea if ever updated, or what the FAA would do now with the potential out.

Tim
 
Morgan3820 said:
So long as the lead stays in the resin matrix and the children don’t eat it, absolutely nothing happens. Same with asbestos.
Not saying any of it is a good thing but people get hyperbolic about things they don’t understand.
Not that your opinion is relevant. Been working and supervising the use of a large variety of industrial chemicals for 35 years. Not little beakers in a lab in a hood. You?
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The problem is that it doesn't stay in the matrix, and children have eaten it. Some lead compounds are sweet, so children are attracted to them. The paint matrix breaks down and the lead pigment becomes dust that is inhaled. That's why lead paint has been banned from use in homes and used minimally elsewhere.

An appeal to your "authority" is a fallacy, as you are demonstrating. What type of chemist I might be doesn't matter. Lead still is a toxin. My opinion is certainly as relevant as anyone else's here.
 
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The sooner we get rid of 100LL the better. Sadly, it sounds like we are still a ways off from that reality. It seems it's the "drop in replacement" for all engines and airframes part that has everyone stuck.

What I want to know is; if there is no lead in the gas, will there no longer be that annoying light brown soot to scrub off the bottom of the plane anymore?
 
Racerx said:
They failed because of their approach. They tried to get a fuel that replaces 100LL across the board. This is like the MOGAS STC. If your plane is part of the STC, you can use it...if you can find it. What's interesting is there's 2 stc's. One is for limited Cessna airframes. And one for a limited number of Lycoming engines. Once testing is done the AML could expand. It took them 11 years to get to this point. I'd venture to say we're at least that long before lead is replaced, and odds are probably less than 50/50 G100UL is the solution.
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But drop-in replacement is what GAMI believe they have achieved. If not, it's for naught. We already have a partial replacement in 94UL.
 
Dav8or said:
What I want to know is; if there is no lead in the gas, will there no longer be that annoying light brown soot to scrub off the bottom of the plane anymore?
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I run auto fuel and still get some brown soot. The problem being rich of peak, I suspect.
 
Oxygen sensors are another good thing that will come about by eliminating lead. They do great things in helping you adjust the richness of your fuel mixture, and they’ve been standard in automobiles for a long time.

They’re available for narrow-range measurement as in cars where they help tweak the mixture to minimize pollution. They’re also available for wide-range measurement which is useful for such things as ROP vs LOP adjustment.

But oxygen sensors are fouled by lead. So to this point their aviation use has been limited mostly to amateur built planes that operate entirely on automobile gasoline.
 
EdFred said:
I've been handling lead with my bare hands for 20+ years on a near daily basis. (around 400,000lbs of it as a VERY conservative number) The issues are WAY over blown.
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Probably because elemental lead isn't absorbed through the skin very readily. I've cast lead bullets and sinkers, and practiced lost wax casting with lead, and soldered tens of thousands of junctions. Not worried about that. Tetraethyl lead? Not going close to it unless diluted mightily with gasoline.
 
When GAMI is tired of doing battle with the feds, they can sell the STC portfolio and methods to a real bad actor like Signature's parent, who can sabotage current 100LL with haste and nudge that 70 cents up to some MBA-approved optimization of profit.

I figure their G100UL investment just reached a peak of value for the next few years. Adding a few more STCs won't measurably move the needle -- the process is secured now. Add the loose money situation and appetite for regulatory capture as an investment... it's sort of a perfect storm to milk GA hard.

I hope I'm wrong.
 
DoubleD said:
But drop-in replacement is what GAMI believe they have achieved. If not, it's for naught. We already have a partial replacement in 94UL.
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Covered early in the thread. But I repeat it again.

PAFI defined drop in replacement as one which meets the current specification for 100LL.
GAMI defined a drop in replacement as one which existing avgas planes can use without mechanical changes.

So, as GAMI proves to the FAA that this is so, expect the FAA to add whole classes of planes to the AML.

Tim

Sent from my HD1907 using Tapatalk
 
So, the FAA might add “all Skyhawks” to the AML, so i can buy and use this new fuel in a Skyhawk without having to buy a STC certificate?

Or will every GA airplane in existence need to buy an STC in order to buy this new fuel (which might become the only GA fuel available in a few years)?
 
WDD said:
So, the FAA might add “all Skyhawks” to the AML, so i can buy and use this new fuel in a Skyhawk without having to buy a STC certificate?

Or will every GA airplane in existence need to buy an STC in order to buy this new fuel (which might become the only GA fuel available in a few years)?
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What did the FAA do with aircraft that used 80 octane (red) or 100 octane (Green) fuel? Was there an STC that said they could use 100LL, or did they just say, "yeah, it's good as a universal replacement" and let it go?
 
Kenny Phillips said:
Probably because elemental lead isn't absorbed through the skin very readily. I've cast lead bullets and sinkers, and practiced lost wax casting with lead, and soldered tens of thousands of junctions. Not worried about that. Tetraethyl lead? Not going close to it unless diluted mightily with gasoline.
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But we aren't pouring TEL on children's cereal or putting in their sunscreen.
 
SoonerAviator said:
What did the FAA do with aircraft that used 80 octane (red) or 100 octane (Green) fuel? Was there an STC that said they could use 100LL, or did they just say, "yeah, it's good as a universal replacement" and let it go?
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There was no STC required. I don't recall whether 100ll went through any kind of ASTM process, either. I used to put red, green and/or blue gas in my O470-powered 182. Interesting question about how many STCs will need to be purchased to use G100UL. It sounds like two, probably as a package (not much use in having only one if two are required).
 
I wonder why they need the airframe STC and not just an engine STC. Maybe they're headed to engine-only STC :fcross:

Pilots running with different engines than stock may be very last or overlooked with the airframe+engine combo approach.
 
schmookeeg said:
I wonder why they need the airframe STC and not just an engine STC. Maybe they're headed to engine-only STC :fcross:

Pilots running with different engines than stock may be very last or overlooked with the airframe+engine combo approach.
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I’m guessing fuel system will be covered by your airframe STC.
 
Well, the O-540 is approved for the mogas stc, but the PA24 airframe is not because of vapor lock issues due to the fuel system. So that's one reason.
 
schmookeeg said:
I wonder why they need the airframe STC and not just an engine STC. Maybe they're headed to engine-only STC :fcross:

Pilots running with different engines than stock may be very last or overlooked with the airframe+engine combo approach.
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No such animal that I am aware of.
STC stands for supplemental type certificate, which applies to the airplane type certificate.

Tim

Sent from my HD1907 using Tapatalk
 
schmookeeg said:
I wonder why they need the airframe STC and not just an engine STC. Maybe they're headed to engine-only STC :fcross:

Pilots running with different engines than stock may be very last or overlooked with the airframe+engine combo approach.
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The auto fuel STCs consist of an airframe STC and a separate engine STC. You need both to be compliant. I suspect this will be the same case here.

Having separate engine and airframe STCs also can solve the question of an aircraft with a non-standard engine too. Both are approved separately. I owned a Lycoming powered Stinson for a while that had an auto fuel STC. Completely legal since the two STCs are separate, even though that engine and airframe combination was not a factory built combination.

One thing I could see happening is the engine OEMs updating their list of approved fuels for specific engines. Lycoming did that a number of years ago to cater to the unleaded fuel market. Perhaps the airframe OEMs may do something similar as well at some point for the supported aircraft.
 
tspear said:
No such animal that I am aware of.
STC stands for supplemental type certificate, which applies to the airplane type certificate.

Tim

Sent from my HD1907 using Tapatalk
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But everyone that upgraded from the 470, They might have an airframe STC to use the fuel but no longer have the dinosaur engine. And if the there's no STC for the upgraded engine...
 
tspear said:
No such animal that I am aware of.
STC stands for supplemental type certificate, which applies to the airplane type certificate.

Tim

Sent from my HD1907 using Tapatalk
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Hmmm.. now that you mention it, yeah, I can't think of any engine STCs. I assumed you could supplement an engine TCDS but.. well hmpf. :D

I wonder what the process is for Lyc or Conti to amend their approved fuel list.
 
There’s an STC for the O-200 crank in the C-85, spin on oil filter etc. No airframe paperwork.
 
schmookeeg said:
Hmmm.. now that you mention it, yeah, I can't think of any engine STCs. I assumed you could supplement an engine TCDS but.. well hmpf. :D

I wonder what the process is for Lyc or Conti to amend their approved fuel list.
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Yes you can amend the engine TCDS. See my response to you above regarding the auto fuel STC. I believe all or most of the oil filter STCs amend the engine TCDS as well. Manac also mentioned a crank STC that doesn’t involve the airframe.

The STC number will give some clues on which TC it is amending.
 
Capt. Geoffrey Thorpe said:
I run auto fuel and still get some brown soot. The problem being rich of peak, I suspect.
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My situation is opposite. I run very lean of peak all the time. The soot is actually a light sand color. Anyhow it takes a bit of scrubbing with solvent to get it off and when I look at the dirty solvent, it looks like a grayish lead color. Hopefully moving to unleaded helps reduce this stuff.
 
All I want to do is buy gas for the plane. It sounds like I’ll need a certificate or two and maybe a DNA sample. Does it have to be this complicated? (Rhetorical).
 
cowman said:
I saw some mention of it being possible that getting rid of the lead might extend our oil change intervals and TBO times. If that turns out to be the case it might offset the extra fuel cost enough to make it a wash.

That said, I'm content to keep burning 100LL for now. If they think it's that important then maybe we need to see subsidies for the STC and for FBOs to make the stuff available. Otherwise I can't imagine very many pilots or FBOs rushing to adopt this and a ton of opposition to mandating it.
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I personally think it’s fantasy to think engine manufacturers are going increase TBO times as they have no incentive to do so and much risk if they do.
 
The sand-colored "soot" is lead bromide.

When burned, TEL (tetra ethyl lead) oxidizes to lead oxide which is the actual octane booster. Unfortunately, lead oxide is solid until about 900C (1652F). To prevent internal solid lead oxide buildup, a lead scavenger, ethylene dibromide is added, which reacts with lead oxide to create lead bromide which is gaseous down to about 250C (482F). Hence, the lead bromide is blown out in the exhaust gas, and when it hits the atmosphere and cools, it precipitates onto your belly as a sand-colored soot.
 
They probably won’t extend TBO - but the reality is cleaner oil free of all that lead sludge will be better for engine life and reliability.
 
Domenick said:
The sand-colored "soot" is lead bromide.

When burned, TEL (tetra ethyl lead) oxidizes to lead oxide which is the actual octane booster. Unfortunately, lead oxide is solid until about 900C (1652F). To prevent internal solid lead oxide buildup, a lead scavenger, ethylene dibromide is added, which reacts with lead oxide to create lead bromide which is gaseous down to about 250C (482F). Hence, the lead bromide is blown out in the exhaust gas, and when it hits the atmosphere and cools, it precipitates onto your belly as a sand-colored soot.
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Well then, it sounds like- get rid of the lead and I get rid of the soot. Great!
 
WDD said:
With all the paperwork - it might be easier to keep the lead and repaint your airplane to a sandy soot color! :)
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It's all just idle musing. I'll probably sell the plane and quit flying long before any of this is a reality. I've heard all these sorts of "announcements" and promised tech just around the corner before.
 
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