Are We Gonna Get A 100LL Replacement Or Not?

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I have my own little axe to grind here and so let the sparks fly. Last month, as part of routine newsgathering duties, I tried to compile a how-goes-it on the FAA’s Piston Aviation Fuels Initiative, or PAFI. This yielded nothing but a waste of time and mounting frustration for me because everyone I spoke to said some version of, "I can’t talk about it.” Or all I can say is something off the record.

Now comes the FAA to announce that the PAFI process—at least the testing—has been suspended because the differences between the two candidate fuels from Swift and Shell and the current 100LL spec are too great. Pray tell what does this mean? And why did it take us four years to learn this? And what happens next? And the big one: Does this spook the market for people about to spend most of a million bucks for an airplane that requires 100LL? Or even a used Bonanza? Does anyone even care anymore? (You can tell us by answering today’s Question of the Week.)

The PAFI process has been impressively successful at one thing: keeping the general flying public utterly in the dark. It was not only designed to be this way, as I understand it, it‘s required to be because of archaic federal rules that kick in at the nexus between government oversight and private industry development efforts. I can see the point, since companies are sensitive about tipping their investment hands to competitors. On the other hand, the level of opaqueness surrounding PAFI is counterproductive, frustrating and something we as citizens shouldn’t accept as good government. Nice ideal, huh? Good luck changing it.

So four years into PAFI—more than two of testing—it looks like we have learned only that the two candidate fuels are too different from 100LL and if I’m reading between the lines correctly, that means neither is the drop-in replacement we had hoped for. Does that then mean that these will be tweaked before more testing? After I reported that the Shell fuel was an effective aircraft paint stripper, I thought that the tweaking had already occurred. And if it had not occurred, why was further testing being done on a fuel no right-thinking pilot would want near his airplane? Many such questions hover over the process with, thus far, no answers that would satisfy even the mildly curious.

With details lacking on the specs shortfall, I can only guess what the issues are. I don‘t think octane is one of them, however. Swift’s entry never lacked for that and at least one source familiar with the testing told me that neither did Shell’s. Swift may have had some problems with cold weather starting and there may be compatibility issues with fuel distribution equipment and the ever-worrisome O-rings and seals. There could be other problems no one foresaw or that simply couldn’t be addressed.

Waiting in the wings are other candidates. General Aviation Modifications Inc.’s G100 may be the most prominent, but Phillips has a project going in conjunction with Afton Chemical, the Europe-based Total and BP reportedly have formulations under consideration but of unknown currency. There may be others. Presumably, or so it said, the PAFI edifice will now examine these as Swift and Shell modify their formulations to fix the shortcomings we aren’t being told about.

Recall that the last official update on PAFI progress was at AirVenture, where the message was that things were going swimmingly. A year later, not so much and the completion schedule has now slipped a full year to December 2019, some 18 months distant.

It’s only logical to again ask why we’re doing this in the first place and you may have forgotten it’s because the EPA was considering a finding of endangerment against tetraethyl lead. That’s still underway at EPA, although an email I sent asking of its status went unanswered. Friends of the Earth, you may recall, has a pending suit that seeks to force the EPA’s hand on the endangerment finding and the group told me the suit is still active, but with no new filings or court action planned. 

There’s an underlying assumption here that the EPA will, sooner or later, act on the lead issue and after 40 years of trying, the aviation industry needs a ready unleaded solution. Given the current administration’s aggressive attitude toward deregulation, I’m not so sure it wouldn’t slow leak the endangerment finding for the foreseeable future. If that transpired, does that reduce the urgency for a replacement? The FAA and the engine industry seem to have decided on an unleaded future, but the timeline is rubbery.

The schedule may very well hinge on what producers of 100LL still in the game wish to do. There’s still money to be made in producing leaded avgas, although the volumes have been in decline. My best guess is that it’s a $200 to $300 million a year profit stream for the refiners blending avgas. For the effort of handling the lead—or getting rid of it and blending an unleaded product—that’s still a business worth being in.

Or so it would seem. On the other hand, nothing in the avgas business has ever been what it seems.





Comments (24)

This Keystone Kops search for a solution is reliant ulon an unchallenged (unchallengeable?) problem: tetraethyl lead in avgas is destroying the planet and all life upon it. Being challenged in my own ways, I'm unconvinced.

But the challenge of the chemistry is undeniable. Here's something to consider: there may be NO chemistry that meets the requirements of a fungible, miscible, infrastructure-compatible, same-mass-density, same-energy-density, same-vapor-pressure, 100+ octane, unleaded aviation fuel. Period.
IF this PAFI fiasco has demonstrated that that's the case, then we can - and must - address the alleged problem in the harsh reality of sunshine.

That, or the EPA can buy brand new airplanes for those of us whose birds REQUIRE 100 octane fuel - pursuant to the "takings" provision of the Fifth Amendment.

Posted by: YARS (Tom Yarsley) | June 10, 2018 7:14 AM    Report this comment

If the FAA pushes this out long enough, then the Lithium Unobtanium Oxide batteries will be available to give our electric airplanes a 1.25 hour range. Sarcasm aside, when the government gets involved, everything takes longer, is more complicated and 10x more expensive than necessary. This is latest fiasco is proof positive.

Personally, I would love to see a 100LL replacement. Engines will last longer, exhaust systems will last longer we will be able to use better synthetic oils and transport of the unleaded fuel will be simpler and less expensive. In the automotive world, tetraethyl lead elimination has been a significant contributor to increased engine and exhaust system life. Although I am not a fan of the EPA and all their junk science, perhaps they are our only hope in pushing the demise of 100LL.

Maybe, the solution is to certify FADEC for the big bore high compression engines that currently need 100LL. FADEC would allow use of lower octane while improving overall engine performance. Currently there are FADEC systems out there that can be tweaked and certified. I have flown the Continental nee Aerosance FADEC on the Liberty XL and found it to be a very good system. The FAA could subsidize owners to so equip. If Uncle Sugar can subsidize electric cars, they can assist in offering a real solution to get the lead out of avfuel.

Meanwhile, I am not holding my breath waiting for a 100LL replacement. Only when we are faced with an actual hard deadline will the bureaucrats stop the games and allow a viable solution.

Posted by: Leo LeBoeuf | June 10, 2018 8:56 AM    Report this comment

As I sit here in the north woods watching the forest in my back yard wither from the fumes spewed out of my buddies C150 that flew overhead yesterday, I got a hearty laugh out of Yars & Leo's comments. You guys made my morning; my wife thinks I've gone nuts when she hears me roaring with laughter in here. :-)

At what point is enough enough? Leo brings up a great point. Cars of today last SO much longer than cars of yesteryear. Airplanes of today COULD run better, start better and last longer without TEL but the problem is precisely that they aren't set up to do so. For gosh sake, we're still flying postwar airplanes because no one can afford anything new in numbers sufficient to replace the fleet any time in our lifetimes. A new airplane set up with computer control and FADEC would be great but who can afford them? We've already given up purple and green and red fuel to get blue fuel ... isn't that enough for the tree huggers?

Unobtainium ... indeed !!

Posted by: Larry Stencel | June 10, 2018 12:02 PM    Report this comment

"We've already given up purple and green and red fuel to get blue fuel ...."

It wasn't given up so much as went away. Once the airlines and military stopped flying big reciprocating engines and switched to jets. the market for purple fuel went away (incidentally, that's why U.S. Navy fuelers on carriers wear purple shirts - it was the color of the fuel they used to dispense).

So, with almost no demand for purple, there was no need to supply it. Thus, a drop in demand for tetraethyl lead additive.

Next, cars starting coming out with catalytic converters. Unfortunately, lead 'poisons' catalytic converters so unleaded automotive gas was born. Now, millions of cars are not buying leaded gas, further depressing demand.

As a result, the demand for tetraethyl lead has declined so much that there is only ONE company in the entire world producing the stuff (they're based in England).

As for the dangers of lead and how much (or little) is too much? It's well known that lead inside the body (ingested or inhaled) is poisonous. But recent studies have suggested that lead, especially leaded gasoline, explain both the rise and fall of crime rates, not just here but around the world:

www. bbc. com / news/magazine-27067615
(remove the spaces to go to the link)

Not only that, engines tend to run better without lead (except, of course, for the lack of octane). The failure of synthetic Mobil-1 for airplanes is due to the lead sludge that built up in the oil.

All that being said - I want to get the lead out, but I don't want to 'throw the baby out with the bathwater'. A solution that's not equal to (or better than) 100LL is no solution.

Posted by: Kirk Wennerstrom | June 10, 2018 1:06 PM    Report this comment

I'm pretty sure GAMI's G100UL fuel has been running successfully in various test aircraft for years. It works and is available now but it does not meet all the specs set forth by the PAFI process. That's why GAMI is choosing the STC route.

Perhaps AVweb could find out the status of GAMI's fuel...?

Posted by: JOHN EWALD | June 10, 2018 5:00 PM    Report this comment

One more reason to go homebuilt... you can build to handle mogas and even ethanol.

Posted by: Robert Gatlin-Martin | June 10, 2018 7:07 PM    Report this comment

The elephant in the room is all of the worlds Tetra Ethel lead comes from one plant in England. If that plant burned down tomorrow all higher performance piston engine planes would be grounded in less than 30 days.......

Posted by: DAVID GAGLIARDI | June 10, 2018 10:33 PM    Report this comment

David, China has been reported as an illegal manufacturer. So not to worry.

Posted by: Rafael Sierra | June 10, 2018 10:57 PM    Report this comment

"One more reason to go homebuilt - you can build to handle mogas and even ethanol"

I'd like to know how homebuilts handle fuel venting differently than certified planes. Because if they're using an 'open' vent like certified planes, then they'll have the same 'phase separation' problem. It's not a certification issue, it's a physical problem.

The below summary is from an ASTM symposium on 'Future Fuels for General Aviation Intermittent Combustion' held on June 29th, 1988, a paper entitled "Investigations into Gasoline/Alchohol Blends for Use in General Aviation Aircraft" by August M. Ferrara, FAA Aerospace Engineer.
* * * * *
The test setup was a ground-based Cessna 172 fuel-system. They tested fuels ranging from a 0% to 15% blend of alcohol mixed with 100LL. Both ethanol and methanol were tested. The systems were both heated to simulate a hot engine compartment, and cooled to simulate high altitudes.

"During the course of endurance runs, the fuel flow, then the fuel pressure would begin to decay, and eventually, vapor lock would occur. This phenomenon was markedly more severe on hot humid days than on dry cool days."

"As the tank was allowed to cool to room temperature following a test where the fuel was maintained at an elevated temperature such as 43degreeC (110degreeF), the blend would become cloudy, then with time, a layer of alcohol, water, and gasoline would settle out in the sump."

"If the fuel was allowed to age overnight in the tanks, there would usually be a phase layer in the sump, even if the sumps were drained the previous day."

"This phase separation problem appeared to result in corrosion problems in the aluminum tanks. Before and after photographs indicate the tanks corroded badly in the short period of time the alcohol blends were used."
* * * * *

It's one thing to build using alcohol-resistant o-rings and anodized fuel tanks and lines. But, unless you have a 'sealed' system like cars (charcoal canister filter/venting, for example), then the ethanol will tend to 'drop out', creating a slug of watery fuel when you least expect it, and reducing the octane of what's left behind.

Posted by: Kirk Wennerstrom | June 11, 2018 5:30 AM    Report this comment

Meanwhile, a lot of us running modern engines find we have manuals that require us to use lead-free fuel (leaded in only small amounts, in emergencies, is okay), and harsh experience has taught that it's best to avoid ethanol in the fuel (phase separation, leading to all sorts of undesired outcomes). And there are only about 20 airports in the country that dispense fuel that is free of both. Even ethanol-free mogas is about as common as periunobtainium.

I was really looking forward to seeing a lead-free fuel achieve widespread distribution. Apparently not going to happen.

Posted by: Thomas Boyle | June 11, 2018 7:19 AM    Report this comment

"Recall that the last official update on PAFI progress was at AirVenture, where the message was that things were going swimmingly"

I've pretty much come to the conclusion that you can't trust any official status that is presented at AirVenture, at least if it's coming from a government agency. They know they'll have shoes thrown at them if they speak the truth, so they just lie and speak to what they think all the knowledgeable pilots want to hear. And if they get called out, it's just their staff's fault for giving them wrong information.

Posted by: Gary Baluha | June 11, 2018 8:21 AM    Report this comment

GA would benefit greatly if that TEL plant in the U.K. burned to the ground. The resulting panic from the FAA and the 30% of GA that burns 70% of the 100LL would force an immediate solution to a problem that currently no one wants to make the compromises or spend the money to fix. For example, you'd probably see G100 fuel at 90% of the country's airports within 30 days of the demise of TEL, which would work for 90% of the fleet. The remaining 10% are going to have to spend the money to upgrade their engines because that's just the reality of converting away from 100LL.

Posted by: ROBERT JOHNSON | June 11, 2018 9:49 AM    Report this comment

MAKE GA FLYING GREAT AGAIN ... do away with the FAA for Class I airplanes !!!

I'm with you, Gary. Listening to the former Administrator spew at Airventure was an insult to me.

Posted by: Larry Stencel | June 11, 2018 10:06 AM    Report this comment

" Listening to the former Administrator spew at Airventure was an insult to me."

I couldn't agree more, Larry. I watched him at the Oshkosh press briefings.

Huerta danced better than Gene Kelly at spinning a story while avoiding the issues. He danced--he pirouetted--he side-stepped--he even inverted the issue with an example of Fred Astair's "Dancing on the ceiling"--everything was inverted. He tapped danced around issues better than James Cagney's famous White House stairway scene in "Yankee Doodle Dandy!"

Posted by: jim hanson | June 11, 2018 10:37 AM    Report this comment

Speaking of Kirk W's comment on fuel venting to a canister in cars, I'm experiencing a problem with one of two identical vehicles I own that sits for six months in Florida when I'm gone. The issue has potential relevance here with airplanes and fuel vapors.

I own two identical GM light duty pickup trucks. One sits for six months in FL and the other up north near Oshkosh, alternately. Neither has 25K miles on it. I park the one in FL and it's running fine. I get back and it throws an engine code for the evap vent purge valve. That valve is supposed to close when an engine vacuum valve is commanded open by the computer to allow suction of the vapors out of the charcoal canister. I also notice I'm having a problem putting fuel in it because the canister is clogged with vapors. On the one up north which freezes to death when I'm gone, I'm having no such problem. Further research yields that failure of GM vent purge valves is a common problem due to the vapors affecting the valve. In my opinion, the heat and humidity of the one sitting in FL all summer is the problem.

Meanwhile, I have an airplane that's sat for two years filled with 100LL and it's as happy as a clam. Some small toy vehicles I have for on airport transport get filled with avgas when I leave to ensure that the fuel doesn't go bad and cause issues. Anyone putting mogas into their airplanes should beware. Even though one airplane has an autofuel STC, I don't use it ... it's for emergency use only.

Posted by: Larry Stencel | June 11, 2018 11:07 AM    Report this comment

John Deakin of Pelican's Perch fame wrote an article for this very publication back in 2002 (Pelican's Perch #55) about leaded gasoline. In it, he outlined the history of avgas research and why there is not likely to be a fully compatible unleaded 100 octane fuel produced, ever. If there was such an animal, the big oil companies would have already found it. Avgas producers HATE leaded fuels. They are toxic, chemically unstable, expensive and have to be carefully segregated from all other products to prevent lead contamination of the other fuels. IF they could get rid of the need for lead, it would greatly simplify their lives and actually make avgas production cheaper and easier.

However, modern fuel blends that make up the 100LL base stock do run at about 95 octane without the lead added. That would work just fine in about 70% of our lower powered engines. For the big, high horsepower mills, addition of a variable spark timing system (like the GAMI PRISM system) would most likely allow them to function at rated horsepower with adequate detonation margins. That may be the closest we can come to a universal lead-free fuel. Yes, it will cost some of us more money to modify the engines, but unlike some FAA mandated programs, it would give a true benefit to everyone involved. If PAFI is looking for the magic fairy dust that will make everyone happy, they need to stop wasting time and go with real world solutions, popular or not.

Posted by: John McNamee | June 11, 2018 12:31 PM    Report this comment

I think John, and others, are right. No fuel exists that will alter the laws of thermodynamics, or the kinetics of detonation. A complete solution will need to involve the power plant.

Posted by: kim hunter | June 11, 2018 10:00 PM    Report this comment

"That, or the EPA can buy brand new airplanes for those of us whose birds REQUIRE 100 octane fuel - pursuant to the "takings" provision of the Fifth Amendment."

If only the EAA, AOPA et al would start fighting fire with fire, and do away with the mea culpa, please may I have another modus operandi.

Posted by: Robert Ore | June 12, 2018 12:07 AM    Report this comment

Funny you should say that, Robert. Just now -- early this AM -- I'm reading about alternate methods of compliance for Part 23 airplanes that came out recently in response to the FAR Part 23 rewrite. The complexity of the process "they" have invented is borderline ridiculous. The final recommendations of the Aviation Rulemaking Committee (ARC) contained in their voluminous report to the FAA Small Aircraft Directorate (Earl Lawrence) were complete and 'good' in and as of themselves. What the FAA produced from it is ridiculous! I don't think even a lawyer could ferret through some of the crap they disseminate.

Then, I was thinking about addressing Jack Pelton at Airventure and what I'd want to talk about. It wound up being just what you said. It's time to stop giving expert oral gratification to their members and start pounding the desk any and every time they get the FAA to Oshkosh or Frederick.

This fuel fiasco is emblematic of the loss of control over FAA's mission. Bureaucratic inertia is the only product the FAA produces anymore.

It's a good thing I ain't running either the EAA or AOPA !

Posted by: Larry Stencel | June 12, 2018 6:32 AM    Report this comment

"It's time to stop giving expert oral gratification to their members and start pounding the desk any and every time they get the FAA to Oshkosh or Frederick."

Surely the FAA would listen to reason. Give'm time Larry.

Posted by: Rafael Sierra | June 12, 2018 8:04 AM    Report this comment

It appears that phase separation only occurs with fuel that contains ethanol/methanol. The ethanol is the issue. Removing that creates a compatible fuel for over 70% of the GA fleet, if not more. We call that mogas when dispensed at an airport.

When i lived in Illinois, I had a hard time getting mogas, either from the airport or the the average gas station. As a former resident of Oklahoma and current living in Arkansas, I can buy "mogas" at any gas station even Walmart. In the south, we are proud of "real fuel" rather than "corn" fuel. My previous 172 and now my Bonanza run better on Walmart "mogas" than the 100LL available at the airport.

Oklahoma's beef industry, lobbied out the "corn" ethanol producers of the state of Oklahoma. The "grain" lobby of Illinois has largely prevented the availability of non-ethanol fuels in Illinois. To me, it is obvious the solution is more political than chemical.

My 20 year old bladders in the Bo have suffered no adverse affects of "mogas'. My pressure carb seals have had no adverse affects. The plugs are always clean, the oil less contaminated, and it starts better.

I have looked at ethanol free fuel that I use exclusively in my 63 Sudebaker Lark, my 78 Dodge D-100, our Chrysler 300C, my Husky chain saw, mowers, etc...and no long term storage issues, no change of color, no apparent phase separation, no need for Stabil, no hard starting even if it is six months long as the fuel has no ethanol in it.

When we were providing flight training in our 172 and 150 based in Oklahoma, we filled 55 gallon drums with "mogas" from the local Valero. We used 87-89-91 octane with no performance differences. Eventually, we used 87 octane exclusively.

We tested every load of fuel for ethanol. I test every "mogas" purchase here in Arkansas for ethanol. So far, in 10+ years of flying with "mogas", i have never found any ethanol contamination issues.

Once again, it says to me, we have a nation fuel distribution system that has already demonstrated its ability to provide unadulterated "mogas". Even at today's fuel prices, I have averaged $2.00 per gallon savings over purchasing matter where I am at if "mogas' is available. When i can't get "mogas", I fill with avgas and pay the "price". However, with a little planning and local investigation, I manage to use ethanol free "mogas" for the majority of my flying. My 0-300 was at 2500 hrs on a 1800 TBO and still running great, no valve issue, great compression, excellent temps, etc running on locally available gas station purchased "mogas".

It's all about the money and "who's oxe is getting gored". Politics rather than chemistry is the biggest hurdle.

Posted by: Jim Holdeman | June 13, 2018 9:49 AM    Report this comment

Alcohol in gasoline is an idea whose time has come and gone. When the EPA originally pushed to remove lead from auto gas, refiners went looking for an octane booster that could replace it. WIth government support and encouragement, they settled on MTBE (an ether based compound) that worked nicely and had minimal impact on airborne pollution. Unfortunately, it had the bad habit of getting into groundwater sources and polluting the drinking water in many parts of the country. So, the government then banned it and went looking again. Thanks to the farm lobby, they sold congress on using ethanol instead. Ethanol has many issues, but one big advantage: It could be made from domestic corn crops, so no problems with imported anything. The program was a Godsend to the midwest corn farmers, but a pain in the tush (and wallets) for the rest of us.

With the recent rise in domestic oil production, thanks to fracking (another hot issue we won't get into), importing foreign oil is much less of an issue now. And, refiners are perfectly capable of producing motor fuels with adequate octane ratings for modern engines without needing alcohol. Ethanol free mogas may cost a little more to produce, but the 15% improvement in gas mileage would offset most of the cost. But, good luck in getting rid of ethanol, thanks to the farm lobby. Many of the previous posts are correct: The problem is more political than chemical.

Posted by: John McNamee | June 13, 2018 11:14 AM    Report this comment

I see elsewhere on Avweb that GAMI's G100 unleaded fuel "has been under almost continuous testing and evaluation since 2010. Braly said the company is continuing testing "out of a hip pocket" and may be done with the FAA-mandated work by the end of the year or early next year"

It looks like these things take time, but nobody complains when a private company takes eight years to test their product.

But when the government finds something wrong with the fuels submitted to it for testing, the old guard complains about bumbling bureaucrats.

Posted by: Rollin Olson | June 13, 2018 1:34 PM    Report this comment

MOGAS is not car gas. MOGAS has no ethanol. The issue is the Government, period, they are here to help, cover your wallet!

Posted by: bruce postlethwait | July 10, 2018 8:45 PM    Report this comment

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