Last week’s blog was more of an update on progress so far on the replacement of 100LL with unleaded high-octane aviation fuels. In the comments section, a reader who uses the title BestGlideSpeed gave a long list of questions and criticisms of General Aviation Modifications Inc.’s (GAMI’s) G100UL.

Many of the points made by BestGlideSpeed have been made by others, and somes we haven’t heard before. GAMI founder and chief engineer George Braly has addressed them in a point-by-point response to the post.

His intent was to post it as a reply to BestGlideSpeed in the comment section, but he agreed to allow us to run it as this week’s AVweb Insider. Here is his intended reply without any editing except to add formatting to make the replies distinct from the assertions made by BestGlideSpeed.

We at AVweb believe this to be the fundamental issue affecting the future of light aviation, and we welcome all comments made with the good faith intention of furthering the discussion. That means we’re inviting any of the players and stakeholders in this issue to use this space to make their views known, with the knowledge that whatever they put forth is open to rebuttal and debate.

Some of what Braly has to say is provocative, and we expect it to bring reaction. Let’s have it.

Russ Niles, AVweb editor-in-chief

BestGlideSpeed posted the long message critical of G100UL Avgas, which is requoted below. On behalf of GAMI, I (George Braly, head of engineering) am commenting on his message. 

                                              ************

I’m not certain if this is a news story, or if Russ just enjoys throwing rocks at a hornets’ nests to see all of the commenters get riled up. At this point no news is simply, well, no news. As an engineer developing new products for market, I understand that a typical, successful development project always includes the following:

1.   Unrealistic demands of what the new product must be able to do.

Not in the case of G100UL. The original design criteria, set out in writing to the FAA in the spring of 2011, were each fully met, and even exceeded.

2.   A never ending system of hurry up and wait. 

Yes. There has been a lot FAA imposed “waiting” and not a lot of “hurry up”

• READ MORE: GAMI Responds To Cirrus G100UL Service Advisory

3.   Unrealistic demands that after everyone sat on their hands burning up the clock, you must now save everyone else’s bacon and get the ball across the finish line in record time.   

No such urgency from the FAA has yet come to light.

4.   Individuals who have no understanding of the science, industry, or use case are the ones setting the project priorities.  

There has, at times, been some of that from the FAA. But mostly the impediments have been designed by the proponents to simply slow the G100UL avgas project down or to stop it, completely.

5.   Self interested individuals continually ignore realities and proclaim “just go with my favorite answer now” because the unresolved concerns fall outside of their very limited set of priorities.  

A lot of that very recently with respect to the coverage of the last 2 percent of the fleet of aircraft—rotorcraft.

6.   The list goes on ad nauseam—and that is when things go well.   

Things went “well” from 2012 to 2015. Then stagnated for four years.  Then went backwards for 6 months. Then, beginning in July, 2020, the Washington AIR-1 assigned a really GREAT new team of engineers and we managed to finish the project in 24 months.

A project that the government gave 10 years to resolve is only four years along. 

The scope of that government project included TWO PATHWAYS TO SUCCESS:  a) The PAFI / EAGLE project and b) The STC pathway. The second of those two pathways is now a resounding success with every single spark ignition engine in the FAA database approved to use G100UL Avgas. No exceptions!

• READ MORE: GAMI’s G100UL Unleaded Fuel Successfully Powers Historic WWII Aircraft

From my perspective, I am impressed with the progress that has been made in that amount of time.    

Respectfully, I would suggest that almost no person in the FAA who is not financially or career “motivated” with affiliation to the manifestly failed PAFI / EAGLE program would agree with you. The taxpayers have spent nearly a quarter of a billion dollars on the failed UL AvGas/PAFI/EAGLE programs over the last 20 years. The taxpayers have absolutely ZERO to show for that expenditure. Ronald Reagan once observed that there is nothing that lasts so long in Washington as a “temporary program.” 

The fact that Russ is proclaiming all to be lost and we need a complete reboot with the FAA jack boot on the neck of fuel manufacturers to obtain it is just adding himself to the list as another obstacle to getting anything done.

On the contrary. Russ’ observations, and Paul Bertorelli’s from 18 months ago, are precisely on point.

• READ MORE: Stains Reported on Wing of AOPA Aircraft Fueled by GAMI G100UL

I give kudos to at least one organization being honest enough to say that a “drop-in” replacement is not possible. 

That statement calls to mind the old Chinese Proverb: One should not tell the Chinaman that he cannot do something he has already done! A full “drop-in” replacement has already been approved by the FAA. Any statement to the contrary is either based on a lack of knowledge, or some hugely contorted definition of the phrase “drop-in” to mean something very different than the meaning given to that term by the FAA and most other participants.

To accept that statement we have to understand what a “drop-in” replacement entails. It is easy to say “I fly behind a Jabiru engine and I don’t need the same octane as some of the big block engines, so let’s just go with XXX”, but that is not a drop-in replacement for the industry. Whatever replacement we ultimately come to will be a system of compromises. 

There is no compromise with the use of G100UL Avgas. In fact, G100UL Avgas is able to allow enhanced performance of the existing fleet of high powered radial engines—by allowing those engines to be up-rated in BHP back to their original war time military ratings.

Some of us will come out of this perfectly pleased, and some of us will be left out in the cold.

No one is left out in the cold—except the major producers of 100LL who have tried to obstruct and delay any development of a “drop-in” replacement for 100LL.

Consider: GAMI’s fuel is not approved for rotary wing. You cannot get rid of 100LL and leave all of the rotary wing aircraft grounded. News helicopters, med-evac, offshore platform, 

Wrong. Every single rotary wing [gasoline] engine is already approved for use with G100UL Avgas. Robinson Helicopter (which makes 80 percent of all of the helicopters) has fully tested G100UL avgas using their independent test protocols that they developed for their testing of PAFI/EAGLE fuels. Robinson has told GAMI that G100UL Avgas is the only unleaded fuel to ever pass their rigorous flight test helicopter profile.  Robinson has written a complete engineering report and that has been submitted to the FAA to facilitate the early addition of the rotorcraft airframes (the engines are already approved) to the Approved Model List.

. . . the list goes on and on.  [If the “list goes on….” Then, please, send me an email and let me know what other items are “on the list.” gwbraly@gami.com.

GAMI’s fuel is approved by the FAA via STC—this approval only means that if I fly a certificated fixed wing aircraft, I am allowed to use it and not get busted by the FAA.   

That is false. The FAA approval means the FAA has found the use of G100UL Avgas to be equally safe, or actually safer than the use of 100LL.  Their words were:  “… as good as or better” than 100LL.

It is not an industry approval, and it by no means is a blanket mandate, indemnification, or adoption. 

There is no such thing as an “industry approval.” Period. Parade Rest.  Nor has there ever been. The purpose of an ASTM specification (by its own terms, in paragraph 1.1, is to facilitate the sale and purchase of 100LL by “purchasing agents.”

It is not approved by the engine manufacturers, it is not approved by the airframe manufacturers,    

Actually, Cirrus has fully tested G100UL Avgas. Recently, the senior manager at Cirrus has told his staff and has told one of the industry groups that “Cirrus has no technical objection” to the use of G100UL Avgas.” 

… it is not approved by the insurance companies.   

Wow. What complete nonsense! You have been reading too many “statements” from Curt Castagna at NATA. 

FACT:  Each of the major distributors has directly advised GAMI directly, that they have obtained the same product liability insurance for their sale of G100UL Avgas as they have for 100LL. Two years ago, the insurers told one of the two largest distributors the following (at Lloyds, in London): “If the FAA approves G100UL Avgas, then Lloyds will insure it.  No additional charge for the premium. FURTHER MORE, Vitol Aviation was able to add G100UL Avgas to its policy with no increase in premium.

… , and it is not approved by the fuel distributors/sellers.  

Actually, each of the major distributors has reviewed the G100UL Avgas FAA approved specification and told GAMI that they had no objection to that specification. Note, distributors and sellers do not approve or disapprove of fuels. And none of them have stated to GAMI that they have any reason to ‘disapprove’ of G100UL Avgas.

The FAA has no authority to mandate via STC that Lycoming engines must run on GAMI fuel that distributors must sell it, and insurance companies must indemnify it. The STC only gives permission to the pilot to buy it.

Correct. Nor does the FAA mandate that Lycoming must approve the use of 100LL or UL94 or UL82. THAT is not the FAA’s job.

We have one fuel that proclaims itself the elixir of all aviation engines, but refuses to allow the industry to examine it. 

WRONG. Wrong, again. And Again. From your series of false statements, it appears that you may be reading too many press releases from NATA and GAMA, and similar organizations. GAMI has in fact allowed the industry to examine G100UL avgas. Lycoming and Continental have each sent engineers to GAMI and have flown G100UL avgas and compared it back to back with 100LL and have each stated to GAMI that they cannot tell the difference in operation when compared to the use of 100LL.

We have another manufacturer that says we are working on the best solution we can, but there is no silver bullet and our solution will not be a drop-in replacement for 100LL. We have a third that is working on it but is keeping their efforts close to the vest.  

That would be LyondellBasel/VP Racing and Swift Fuel. Both of the sponsors of each of those two fuels have acknowledged, publicly, that neither of those two fuels will be able to be used on the higher performance portion of the fleet (8.5:1 CR N.A. engines and turbocharged engines) without substantial engine modifications and/or limitations added to the operating instructions.

I doubt that GAMI’s fuel is as perfect as they claim. 

GAMI has never claimed it is “perfect.” Please do not make false accusations.

There are too many red flags. In the end, there will be compromises.

Please elaborate and identify the “red flags” and the necessary “compromises” which you, in good faith, believe to exist?

We may need to move to multiple fuels to provide a simple well performing fuel to those who do not need such high octane, and a “compromise” version of 100LL that the EPA can live with in smaller quantities for the larger engines, rotary wing engines, and any others that absolutely require the higher octane.

We may need to choose a boutique fuel that gets us most of the way there, but only after modifications to the engines that require higher octane.

The thought embodied in the previous two paragraphs may well be some of the worst proposals and/or concepts for a “solution” to the TEL lead problem ever articulated in public. Either or both would be a disaster for general aviation piston powered aircraft owners.

Likely, we will need to kick the can down the road and extend the 10 years. The amount of lead contributed to the environment by aviation fuel is infinitesimally small when compared to the world’s annual consumption of lead—so small that is not measurable in the environment.

Yes, the lead contribution is small. But continuing to be a “lead denier” will likely not work out well. In addition, the benefits we have all enjoyed in the automotive world from getting rid of the lead will also take place in aircraft engines. Double or triple the oil change intervals.  No more routine cleaning of spark plugs. Likely, in our future, greatly extended TBOs. All of those are likely to occur.

There is no perfect solution, and typically it is not the first suitor to knock on your door. We have 10 years to fully develop every option and then make a well informed decision about the compromises that we will need to make as an industry.

Respectfully, if you think the States of California, Oregon, Washington, Colorado, Wisconsin, New York, and a number of others are going to wait more than another 12 to 24 months, then you are not well informed with the activity going on in those states.

For those who want to see GAMI be central to that solution, my recommendation is that GAMI take advantage of the next few years to continue to perfect their product and completely satisfy the testing requirements of every industry group out there. 

A) No “industry group” has even come to GAMI to make any suggestion for any further “testing”. B) Please provide some details as to what aspect of G100UL you believe needs to be improved upon?

They should resolve the limitation that excluded rotary wing. 

The addition of helicopters to the AML STC is nearly completed. See the previous comments on that subject about Robinson.

They should be testing their fuel with Lycoming, with Continental, with Jabiru, with Rotax, with ASTM, with Cessna, and with Piper.   

G100UL Avgas has already been rigorously tested to the FAA’s highest standards. Lycoming and Continental have both tested G100UL and found no deficiencies. Nor have they pointed out any to GAMI.  

NOW HEAR THIS: ASTM DOES NOT TEST FUEL! ASTM considers testing done by fuel sponsors—just like the FAA—and then only writes a specification. Which is not approval to even put one drop of fuel in the wing of an aircraft.

They should include representatives of insurers and distributors in those efforts.    

GAMI has done that for distributors. Insurers do not get involved in any such activity. Where on earth did you come up with THAT concept?

Sitting on their secret formula and saying “we don’t trust anyone” is doing themselves no favors while their competitors work diligently for a solution that the industry can openly embrace.

Obviously, once again in the long series in this response, you are not well informed. The complete specification for G100UL Avgas, Revision-12C9 has been posted on GAMI’s web site www.g100ul.com and, more specifically, https://www.g100ul.com/faq#specification since before Oshkosh. In addition, any of the distributors and/or OEMs that has asked to see that document have been furnished that document, over the course of the last several years.

The post GAMI Answers G100UL Criticisms, Point By Point appeared first on FLYING Magazine.

The Baron is being used as a test bed to compare the performance of General Aviation Modifications Inc.’s (GAMI’s) G100UL unleaded avgas with 100LL. The stains are on the wing with the tank holding G100UL, but it has not been determined that they came from the fuel.

• READ MORE: GAMI Responds to Cirrus G100UL Service Advisory

“We have scheduled a mechanic to determine the cause of the leak coming from the left wing of the Baron, which should happen in the next few days,” AOPA senior vice president for media Kollin Stagnito told AVweb. “We are not yet sure what the substance is, nor where it is coming from.”

Word of the stains has been a hot topic on various forums, and speculation is rampant as to their cause.

• READ MORE: Unleaded Fuel Debate Heats Up in Oshkosh

GAMI chief engineer George Braly told AVweb the cause is most likely a faulty or improperly installed fuel cell bladder or patch inside the bladder. Braly said the bladders in the Baron may be more than 40 years old. He said G100UL has been tested for compatibility with the bladder material and there were no problems. He also added that fuel bladder leaks are a relatively common issue with Barons.

Editor’s Note: This article first appeared on AVweb.

The post Stains Reported on Wing of AOPA Aircraft Fueled by GAMI G100UL appeared first on FLYING Magazine.

During the public comment period after formal presentations, Tim Roehl, president of General Aviation Modifications Inc. (GAMI), challenged a couple of points made during the presentations of members and support staff from the End Aviation Gasoline Lead Emissions. He told the crowd—smaller than in previous years—that contrary to assertions made during the formal part of the forum, GAMI’s G100UL is indeed ready for distribution and sale.

Eliminate Aviation Gasoline Lead Emissions (EAGLE) initiative member Pete Bunce, president of the General Aviation Manufacturers Association (GAMA), stood up and dismissed Roehl’s assertion.

“I totally disagree, but that’s a discussion for another day,” said Bunce.

• READ MORE: GAMI’s G100UL Unleaded Fuel Successfully Powers Historic WWII Aircraft

In earlier comments, Bunce said his organization remains adamant that any new fuel will be approved through “transparency and a peer reviewed process,” which has traditionally been done through ASTM International.

“Transparency is so absolutely vital for us,” said Bunce.

Refiner Vitol Aviation has 1.3 million gallons of G100UL in tanks in Louisiana and says it has been completely vetted as ready for sale through its supplemental type certificate (STC). GAMI and Vitol have consistently said the FAA approval of an STC covering all gasoline engines on the agency’s registry satisfies all the regulatory and safety requirements to begin retail distribution of the fuel, but there are critics who contend it needs a consensus standard determined by an independent organization like ASTM to satisfy concerns about materials compatibility.

Aircraft Owners and Pilots Association (AOPA) president Mark Baker said his organization is using G100UL in a Beech Baron it operates and, based on the 200 hours of experience with the fuel, “GAMI is as good or better” than 100LL. He also said the process has to “move forward” to get the correct fuel.

• READ MORE: Cirrus Service Advisory Throws Fuel on G100UL Maintenance Debate

The balance of the meeting was a reiteration of the stated goals of EAGLE, which increasingly has become focused on maintaining the supply of 100LL. The existence of the commercial quantity of G100UL has prompted politicians in California and Colorado to try to ban 100LL in favor of filling airport tanks with G100UL. Legislative and legal initiatives in both states are moving through their respective processes.

Meanwhile, testing of the last remaining candidate under the congressionally mandated Piston Aviation Fuel Initiative (PAFI) is slowly progressing at the FAA’s Atlantic City, New Jersey, test facility.

About 23 percent of materials compliance testing, 25 percent of durability testing, and a few percent of several other categories have been done on Lyondell/Basell/VP Racing’s entry. It’s also been fully tested on the airframe of a Lancair Legacy and on a Continental TSIO 550K engine.

Editor’s Note: This article first appeared on AVweb.

The post Unleaded Fuel Debate Heats Up in Oshkosh appeared first on FLYING Magazine.

The aircraft took off from Ada Regional Airport (KADH) in Oklahoma and flew over Lake Atoka during the 60-minute flight. According to GAMI, the warbird’s 2,000 hp Pratt & Whitney R-2800 Double Wasp engine is the most powerful to fly on the G100UL fuel.

• READ MORE: GAMI Responds to Cirrus G100UL Service Advisory

“This big-bore radial engine operating at up to 48-inch MP demonstrates the excellent high-octane performance of the G100UL high octane unleaded avgas,” GAMI said in a statement. “The ability to successfully operate this engine as such on an unleaded fuel supports the continued operation of these and many other warbirds well into the future.”

Editor’s Note: This article first appeared on AVweb.

The post GAMI’s G100UL Unleaded Fuel Successfully Powers Historic WWII Aircraft appeared first on FLYING Magazine.

The issue of what is legal (in FAA terms) and approved (by manufacturers) puts maintainers in a sticky situation. On one hand, the FAA issues a supplemental type certificate (STC) allowing for products to deploy on aircraft, but the engine and/or aircraft manufacturer may not approve or recognize the STC as something permitted for use under the terms of their warranty. 

Whether an aircraft owner or operator chooses to use the alternate fuel or not is a matter of choice. The fuel has been approved by the FAA and is perfectly legal to use in the SR series aircraft. The dilemma for the maintainer arises upon returning a Cirrus aircraft to service even for something as routine as an oil change. 

• READ MORE: Identifying Corrosion in All Its Forms

Consider this scenario. The pilot opted to refuel with G100UL or the aircraft arrived with G100UL in the tank. This alternate fuel is a drop-in replacement, so 100UL could have been added to 100LL already in the tank. Granted the maintenance action in this case did not involve fuel, but the maintainer is signing for the entire aircraft to be returned to service. If they sign the repair IAW OEM guidelines, this includes Service Advisories (including one that prohibits the use of G100UL fuel). Consequently if the aircraft is carrying G100UL, then this could be an issue because the aircraft is not being returned to service IAW this Cirrus SB.

Of course, as with any guideline, the issue of signing for an aircraft is subject to interpretation. I know mechanics that will only work on aircraft they have personal history with and do not want to return to service an inherited unrecognized maintenance action.

In the advisory (SA24-14) “Transition to Unleaded Fuel and Use of Non-Cirrus Approved Fuel in SR Series Aircraft” released June 18, Cirrus said it was committed to the industry’s transition to unleaded fuels, which is underscored by its collaboration with stakeholders such as the Aircraft Owners and Pilots Association (AOPA), General Aviation Manufacturers Association (GAMA), FAA, and Eliminate Aviation Gasoline Lead Emissions (EAGLE) industry initiative.

Aircraft and engine manufacturer’s are extremely risk averse. They historically do not recognize alternate methods of airworthiness, and this includes STCs, parts manufacturer approval (PMA) parts, and designated engineering representative (DER) repairs.

There is a commercial element to this since any aftermarket PMA part procured from a third party is a revenue lost for the OEM. It appears the reason for the SB in this specific case is Cirrus’ concern about the breakdown of a fuel tank sealant that was seen in an isolated (one) aircraft known to have been fueled with G100UL.

The company will need to vet this against other aircraft in the fleet to ascertain if the perceived breakdown is an isolated outlier related to the drop-in fuel, or if the dislodged fuel tank sealant was a manufacturing defect unrelated to the use of G100UL. 

• READ MORE: 5 Attributes of a Top-Notch Maintenance Provider

“While some aspects of the initial Cirrus testing of the GAMI G100UL fuel are encouraging, other areas, including materials compatibility, remain inconclusive,” the advisory said. “At this time, Cirrus does not approve the use of GAMI G100UL fuel in Cirrus SR Series airplanes. Per Continental and Lycoming, only approved fuels may be used for an engine to be covered by warranty.” 

According to the FAA, G100UL is safe to use, hence the STC approval. This took years of testing to clear the milestones. In fact GAMI uses the fuel in its company SR22..

According to GAMI, the fuel has undergone substantial testing and displayed no issues on other aircraft. The company also disputes Cirrus’ claim that using G100UL voids the warranties on engines supplied by Lycoming and Continental, however, the engine manufacturers have confirmed its use could affect warranty claims, according to AVweb. 

Tim Roehl, president of GAMI, indicated that his team is drafting a formal response to Cirrus Service Advisory SA24-14 to be posted on its website. Roehl also said that the sealant Cirrus references is not the polysulfide sealant more commonly used in the industry but a polythioether sealant. Roehl stated that G100UL has been in service since 2010 on one wing of the company’s Cirrus SR22, using the same polythioether sealant Cirrus uses, with zero incidents.

The FAA does not comment on specific OEM warranty policies but the agency has reiterated that GAMI’s G100UL does have the STC approval. This is not uncommon as the FAA routinely approves alternate solutions without the buy-in from OEMs. The burden is on the third-party solution provider to prove airworthiness—i.e. STC holder, PMA manufacturer, or designated engineering representative for DER repairs.

What This Means for Maintainers

This fuel issue places aircraft maintenance professionals in a bit of a quandary. On one side, you have the FAA approval for G100UL, but at least one aircraft manufacturer, Cirrus, and one engine manufacturer, say they are not approved via service advisories.

The FAA typically steers clear of airframe/powerplant OEM issues until they become an airworthiness directive (AD). To assist in clearing any confusion, the agency issues periodic documents to help owner/operator/maintainer stay abreast of the situation. One such publication is the FAASTeam service bulletins.

When asked if service bulletins are mandatory, the FAA says: It depends. 

Here is a quick agency ruling: “If you are operating your aircraft under 14 CFR part 91, a service bulletin is advisory, and compliance is not mandatory unless it is included in an Airworthiness Directive.”

Another resource is FAA Advisory Circular AC 20-114, which addresses manufacturers’ service documents: “Service documents should be neither treated nor represented as the official FAA approval documents, unless either a letter of design approval from the FAA or a record that compliance has been determined by an FAA designee is on file for recommended actions indicated as FAA-approved in service documents.”

That said, service documents are beneficial and transmit a wealth of knowledge. When returning aircraft to service, it is critical to list if the action is in accordance with OEM information or another alternate form of maintenance. This comes into play when installing PMA parts, or an STC like G100UL.

The post Cirrus Service Advisory Throws Fuel on G100UL Maintenance Debate appeared first on FLYING Magazine.

More importantly, according to Braly, after testing the fuel received a certificate of authenticity (COA), which then makes it “commercially available.”

• READ MORE: Long-Term Unleaded Fuel Test Begins in AOPA Baron

With the announcement, Braly and GAMI hope to counter critics that say while the fuel has received FAA approval for use under the STC process, it’s not commercially available. The term is important because of a consent decree taken in California that could force the changeover to an unleaded fuel when an alternative to 100LL becomes commercially available.

• READ MORE: G100UL Unleaded Avgas Flight Trial

Editor’s Note: This article first appeared on Kitplanes.

The post GAMI Says It Has 1 Million Gallons of G100UL appeared first on FLYING Magazine.

In this video, The Aviation Consumer’s Larry Anglisano Zoomed up with Audio Authority founder and CEO Jon Sisk, who recently conducted an exhaustive G100UL flight trial in his Lycoming-equipped Van’s RV-14, White Lightning. Sisk made side-by-side engine data comparisons burning G100UL and 100LL and reported his findings, while offering some advice on how you can add this approved fuel to the aircraft’s published operating limitations.

Editor’s Note: This video was produced by Aviation Consumer magazine.

The post Aviation Consumer Live: G100UL Unleaded Avgas Flight Trial appeared first on FLYING Magazine.

The project launched this week with the introduction of GAMI’s G100UL during initial flights in Ada, Oklahoma. Beginning with a baseline of two freshly overhauled Continental IO-520 engines, the Baron will be operated under AOPA management, with the cooperation of Savvy Maintenance founder and technician guru Mike Busch, using the company’s computerized diagnostic tools to analyze engine data and compare it against the information it has collected from “hundreds of thousands of hours of GA flights,” according to an AOPA release.

• READ MORE: Time to Get Serious About Unleaded Fuel

An AOPA spokesperson told FLYING that the association is staging in Ada right now “since that is where the majority of the fuel is, and it makes sense to use [it] as a geographically appealing hub.” Presumably this will allow AOPA the “best efficiency in demonstrating the fuel to a wide range of people.” GAMI’s fuel obtained a supplemental type certificate, covering a broad range of piston aircraft, from the FAA in September 2022. The initial STC for Lycoming O-320, O-360, and IO-360 engines came in July 2021. 

• READ MORE: GAMI Gaines Avgas STC for Pistons on Unleaded Fuel

AOPA president Mark Baker was at the controls for the demonstration flight to kick off the program on October 31. For one hour, Baker flew with G100UL feeding the left engine and standard 100LL powering the right one.

“We wanted to get some actual experience with a 100-octane unleaded fuel in the kinds of airplanes and engines that our members own and fly,” said Baker. “This fuel has been tested extensively in labs and received an FAA STC. Should the FAA approve additional fuels, we’ll test them, too, so we can see what they’re like to use out on the airways.

• READ MORE: GAMI Now Selling STCs for G100UL

“George Braly and GAMI have done a great deal of pioneering work preparing for general aviation’s unleaded future. We’re staging the AOPA Baron at GAMI’s headquarters in Ada first to try out its G100UL.”

The post Long-Term Unleaded Fuel Test Begins in AOPA Baron appeared first on FLYING Magazine.

Because of the way the U.S. government operates, particularly under the Clean Air Act of 1970, certain processes within the associated agencies, including the FAA, could not begin without the finding.

Now leadership from within the industry’s manufacturers, distributors, associations, and users (that’s us, the pilot community) can act on the commitment to getting the lead out of our avgas—specifically the high octane fuel required by high-performance piston engines currently served by 100LL.

But what happens now? I spoke with Walter Desrosier, vice president of engineering and maintenance for the General Aviation Manufacturers Association, this week about the finding and what it triggers. “We have significant progress,” said Desrosier. “There is a broad, collective community commitment from the entire GA industry in cooperation with the government and the FAA to move to no lead. So the EPA action that came out is part of that transition process. It actually puts into the Clean Air Act process how they will mandate a transition. So this is not something that we continue to talk about, that we hope to find solutions—this is a commitment  from the industry that continues to work towards the best solutions.”

The timeline has officially begun, but it will take a couple of years for the mandate and the associated guidance to come into play. In the meantime, the industry is already working hard toward fielding the solutions.

Fuels in Process

Those solutions include four candidate fuels in the works from different providers in varying states of development, testing, and acceptance. “Part of our transition will also be what’s the best available fuel,” said Desrosier.

By most measures, the furthest along comes from GAMI Inc., whose G100UL has attained supplemental type certification from the FAA. GAMI works with at least one producer, VTOL, to manufacture the fuel in enough quantity to reach those who need to test it and develop its distribution in the field. The STC means the FAA considers the fuel safe for the applications covered in that approval.

While the STC includes broad fixed-wing piston aircraft acceptance, testing continues for rotorcraft with Robinson deep into its program with the fuel. Cirrus Aircraft is also testing the fuel within its fleet.

But any fuel that makes it to market must also demonstrate commercial viability. It must make it from the manufacturer through the distribution channels—pipeline or trucking—to the airport where it goes into a tank, and then into our fuel tanks on aircraft. That means the fuel must be acceptable in each of those steps by the businesses involved, as well as the end user burning it in flight.

“With the GAMI fuel, the path that they chose to take is to do their proprietary STC approval, which is perfectly fine on the safety side with the FAA, but they also chose not to enter into an ASTM consensus specification process,” said Desrosier. “Typically that’s how all the other stakeholders in the community become familiar with a fuel…the content of the fuel, the understanding of the evaluation and the assessments of the fuel, and the understanding of the components, and the understanding of the business risks related to being a stakeholder who might purchase, who might produce, who might distribute, who might dispense, and who might put it into people’s tanks.

“There’s a lot of business decisions in this, and a lot of risk.”

Swift Fuels has already entered the market with a lower octane unleaded fuel, 94UL, with limited distribution now but a growing foothold, especially in states and at airports where there is more pressure to get away from leaded avgas.

Swift is pursuing both an STC and ASTM path with its high octane fuel, 100UL, and it has chosen a clever way to gain market acceptance—and perhaps reach commercial viability—with the new fuel. For its current 94UL, Swift offers a “Forever STC,” through which an operator purchasing the STC for the lower octane fuel is promised that the STC for the 100UL fuel will be  included in that purchase when it’s available.

Swift will be able to deliver the fuel through the existing infrastructure to the existing tanks it has put in place for 94UL. According to Desrosier, Swift has already started the consensus standard and is going through the STC process. Critically, the manufacturer will share the results through the consensus process, and when it obtains FAA approval, it will share that data with all the stakeholders.

Two other fuels are pursuing approval through the PAFI (Piston Aviation Fuels Initiative) program. One already has the ASTM test specification, produced by Afton Chemical/Phillips 66, and it is continuing to share information, according to Desrosier. It has to go through the full ASTM testing process, but it has “the roadmap” to do it.

The other candidate fuel (Lyondell/VP Racing) is close behind. The consortium has entered into the specification process and expects to also share its progress.

More than One?

One big question in my mind: Will we end up with more than one fuel, and will they be intermixable? I asked Desroiser, along with the follow-up question: Is this testing pathway defined or is it wait and see?

No, said Desrosier, the fuels are not allowed to intermix and co-mingle. All of the candidate producers are testing to comingle with 100LL—because that is part of the transition process and very likely to occur in the field.

“In terms of ‘could be,’ it depends on the final composition of the fuels,” he said. “We do know some of the key components,” and some fuels will not be able to mix because they are too different.

In the end, having two fuels make it through the process means that the market will decide—and we will have a backup in case of an unforeseen issue with a producer or fuel. “We think it’s going to have to be a market decision,” said Desrosier. “I’m not expecting a significant market penetration, dividing the market in half” with different fuels regionally available.

“Once you have the acceptance by FAA, ultimately the consumer is the very last in the supply chain,” he concluded. 

With the pilot or owner-operator, it often boils down to price—and that won’t likely change with 100UL.

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EAGLE—which stands for Eliminate Aviation Gas Lead Emissions—includes partners from aviation industry associations, the FAA, fuel producers and distributors, airport operators, and local community and environmental experts. With the aim to transition away from leaded avgas—100LL—by 2030, EAGLE has the twin missions of supporting development of replacement fuels and advocating for the continued supply of current fuels until the OEMs, operators, and pilots feel secure in the safety and security of the new fuel source(s).

It’s a tall order. Though four entities reported significant progress with their specific candidate fuel, there are varying degrees of confidence in both the composition and distribution prospects of each one.

The EPA’s Next Step Lies Ahead

And time is of the essence—though it’s not prudent to panic yet, according to leaders like Chris D’Acosta, founder and CEO of Swift Fuels, which is currently working on one candidate fuel. What would trigger that response? The Environmental Protection Agency announced its proposed endangerment finding on leaded avgas last October, and it stands to finalize that this October, on schedule.

What does that mean? It doesn’t mean that leaded avgas will be banned immediately. At the briefing, General Aviation Manufacturers Association (GAMA) president and CEO Pete Bunce outlined the steps that would follow the finding. “The people that have to implement the rules are [at] the FAA,” said Bunce of the next steps following the endangerment finding. “There’s a very structured process.” He estimated that there would be about two or three years to completely field the transition fuel. That’s part of the reasoning behind the 2030 goal EAGLE set, to work through this “very methodical process.”

“We have smart people working in these four companies, and we’re going to have a solution,” said Bunce.

• READ MORE: UND Aerospace Transitions Full Fleet to Unleaded Avgas

Four Fuels

Representatives from each of the companies or partnerships working on those fuels presented their progress, starting with D’Acosta. 

Swift Fuels

Eight years ago, Swift Fuels began delivering the first batches of its UL94 unleaded avgas, and it can now be found in roughly 81 locations across the U.S. The current fuel serves as a drop-in replacement for 130,000 aircraft on the registry—for which FLYING awarded Swift its 2023 Innovation Award. The success of UL94 sets the stage for its higher octane 100R fuel that will serve the remainder of the GA fleet. Swift followed a dual certification program with UL94, acquiring ASTM acceptance as well as supplemental type certificate approval from the FAA. It is pursuing the same path with 100R.

Swift offers a “forever STC” that covers the UL94 as well as future fuels, along with all of the placarding and any changes in documentation. The underlying goal is to establish a sense of security among those who will put the fuel into their tanks—both at the airport and on the airplane. “The emotional uncertainty at this time is really counterproductive to everybody’s interests,” said D’Acosta.

GAMI

George Braly of General Aviation Modifications Inc. presented next, reporting on the nearly 14 years since GAMI began development on its unleaded avgas replacement—and culminating with the issuance of its blanket STC for all aircraft powered by spark-ignition engines in September 2022. “GAMI has fixed the problem,” said Braly, summarizing what had been the general feeling at the time of the STC’s debut. GAMI is working with OEMs like Robinson (for rotorcraft implementation) and Cirrus in its SR22T, considered one of the most complex powerplant installations to accept the new fuel. 

While the STC has been available for nearly a year, GAMI is still struggling to supply the fuel to the market. To this end, Braly announced it had partnered with “an extremely large producer of aviation jet fuel,” VTOL, to produce the G100UL in quantity. That Houston-based company has finished its 4 million-gallon tank toward making that happen.

LyondellBassell and VP Racing

Two of the fuel developers are pursuing approvals through the Piston Aviation Fuels Initiative (PAFI), established by Congress to achieve fleet authorization through a collaborative industry-government process. LyondellBassell/VP Racing is the first of these. VP Racing is a Texas-based developer of fuels and additives for the automotive racing industry, and LyondellBassell produces high-octane lead components for automobiles. In his remarks at the briefing, Dan Perot of LyondellBassell admitted the partnership was “relative latecomers to this race,” as it started in 2018 to develop its answer to the high-octane avgas question.

“We chose to stay with the PAFI program despite delays during the COVID period,” said Perot, “because we felt that it provided the best mechanism for us to learn what the industry needed, communicate with the FAA and OEMs, and secondly, and maybe most importantly, it required ASTM certification for the fuel.” 

According to Mark Walls of VP Racing, the partnership’s fuel meets all D910 specs, is of the same density as 100LL, and is poised to be cost-competitive. The company is about to enter “full-scale” testing after preliminary work in Lycoming and other engines. Like other fuels in development, Walls said its avgas is fully compatible with 100LL in case of mixing in aircraft tanks.

Afton Chemical and Phillips 66

The second partnership pursuing PAFI-based authorization is between Afton Chemical, headquartered in Richmond, Virginia, and Phillips 66. The pair are also working on new lubricants to accompany the high-octane unleaded fuels. Enrico Lodrigueza with Phillips 66 updated on its progress, detailing the candidate fuel, which uses manganese—a coenzyme used in the human body to break down carbohydrates and proteins, a transition metal—to replace the tetraethyl lead in 100LL. The fuel has an ASTM specification in place, ASTM 28434, according to Lodrigueza, which is “substantially similar” to the D910 spec for 100LL.

Lodrigueza characterized the manganese-based octane booster in use. “Manganese is not a heavy metal. That’s one major difference…it’s an essential nutrient.” As far as testing, the partnership has had “a lot of vetting” by subject matter experts and is ready to proceed with detonation testing at the Tech Center on a Lycoming engine. As with all of the potential replacement additives, close scrutiny is being placed on what issues may occur with the new element in the fuel, such as spark plug fouling. The lubricants testing will also ensure compatibility with whatever oil is in use, for example.

What’s Next?

Clearly, the four candidate fuels are in different states of availability for testing—some more broadly than others—and both the engine and airframe OEMs are eager to keep going. Bunce summarized the position of the manufacturers. “We have the money, our manufacturers have the money to purchase it, to be able to go and look at that fuel and understand what chemical components are in relation to the spec to be able to run it and to do the type of testing that we feel comfortable that we can put our families into that aircraft employing that fuel. And if we see good or bad, we will share it, as manufacturers, to the FAA., That’s our obligation—but that’s the right thing to do.”

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