Frequently Asked Questions

Swift Fuels has outlined our general expectations of the transition to Unleaded Avgas in a Whitepaper Click Here to View It

First, note that the transition to unleaded avgas actually began in 2015 with the introduction of UL94 unleaded avgas into the US marketplace. This allowed pilots of piston aircraft, airports/FBO’s, and communities to understand the basic merits of unleaded avgas, including longer oil change intervals, clearer engine operations, no lead-fouling, no toxic lead exhaust emissions, and various other factors that help to promote longer engine life. The idea was to educate the market to better understand unleaded avgas fuel properties and the operational implications – albeit with a 94-motor-octane fuel that was FAA-approved a large portion of the aircraft in the US piston fleet.

Since November 2024, Swift’s premium 100-motor octane unleaded avgas called “100R” has been deployed for selected aircraft models used at flight schools in US and Europe. Also, during this time, Swift’s 100R fuel earned an ASTM International production specification called “D8603”. By September 2025, 100R has been commercially available and sold in US sites plus in Germany, Netherlands, Austria, and Belgium. As of July 14, 2026, 100R is now FAA certificated (via STC) for over 1,200 engines and 1,600 airframes and thus we expect over 100 US airfields along with EU, UK, Canada and Australia to adopt the use of 100R over the coming months.

100R is a high performance 100-motor octane fuel (same as 100LL but without toxic lead) which also includes a Swift Fuels proprietary additive to keep the engine clean, prevent valve wear and intake coking, and maximize the long-term durability of the engine.

If you have questions pertaining to your airport’s role in the transition to Unleaded Avgas, please contact Swift Fuels Contact Us Here.

If you have misplaced your Swift Fuels Avgas STC paperwork or need to make corrections, please contact Swift Fuels Contact Us Here. 

EAGLE is a recently formed collaboration, announced in February of 2022, between FAA and a number of aerospace industry trade groups to support the FAA-certification and transitional activities to replace 100LL with unleaded avgas.

Information about EAGLE programs and its activities can be found here. The industry portion of the collaboration is currently lead by eleven trade groups, including those outlined here:

• Aircraft Owners and Pilots Association (AOPA)
• American Association of Airport Executives (AAAE)
• American Petroleum Institute (API)
• Experimental Aircraft Association (EAA
• General Aviation Manufacturers Association (GAMA)
• Helicopter Association International (HAI)
• National Air Transportation Association (NATA)
• National Business Aviation Association (NBAA)

The EAGLE program includes a reconstituted FAA team working on revisions to the original PAFI program (basically FAA’s central fuel certification program for unleaded avgas). And Swift Fuels has been and will remain engaged in an ongoing collaboration with EAGLE on a number of issues.

Swift Fuels has chosen to engage in the FAA’s Supplemental Type Certificate (STC) program as our primary certification approval process for our 100R unleaded avgas. Our 100-octane STC program to fully replace 100LL has been ongoing for over 2 years prior to the formation of EAGLE and is on a path to produce and deploy our 100R unleaded avgas product into the US market sometime starting in 2024. In May of 2026, Swift Fuels elected to join the PAFI engine test  program – however at this time we do not want to compromise the proprietary methods and stakeholder safeguards that come with our current STC programs. Swift Fuels has challenged the EAGLE program seeking to clarify issues on pilot safety, fuel handling/intermixability during deployment, aircraft risk assurance, communication fleetwide approvals, and similar matters that impact liabilities and indemnification as a result of PAFI’s FAA-managed testing. All these discussions are ongoing..

Swift Fuels STC programs – including UL94 and 100R unleaded avgas products - are designed for pilot safety.

• We provide specific FAA-approved instructions to pilots based upon their specific engine and aircraft requirements
• We stand behind engine/airframe OEM endorsements and warranty provisions for our fuel all tied to ASTM specifications
• We provide fuel handling protocols, aircraft placards and engine tags to confirm accurate compliance with our fuels
• We maintain an active database of registered STC recipients for updating our FAA certification documentation
• We provide clear and unambiguous documentation along with insurance information on product liability
• We monitor the airfield infrastructure to identify and mitigate issues that may pose deployment challenges
• We proactively monitor and communicate with our fuel stakeholders on a global basis

100R is our 100-Motor-Octane Unleaded Avgas product that is designed to support 100% of the US and the global piston aircraft fleet.

100R contains clean-burning, high-performance, renewable oxygenates to boost the octane value and thereby replace toxic lead used in 100LL. 

100R complies with ASTM D8603, an international production specification that controls fuel quality on a global scale. 

100R has the same minimum performance standards as 100LL, including: motor octane number (MON)> 99.6, Supercharge rating > 130, and RVP of 38kPa.

100R has the same density as 100LL - 5.9 lbs/gal.

100R is fully intermixable with 100LL in any ratio. For more information on intermixability, see our Service Instruction SI-1, here.

100R has demonstrated material compatibility on all fuel-wetted surfaces that is consistent with or better than 100LL performance. 

100R has a Swift Fuels proprietary additive that limits deposits and corrosion and reduces the likelihood of intake coking, valve sticking, and valve seat recession while keeping the engine clean. 

100R has superior overall performance compared to UL94 unleaded avgas.

YES - 100R is designed to be drop-in ready across the global piston fleet. It is being evaluated by FAA engineers to confirm it meets the global fuel requirements for piston aircraft without having to replace aircraft hardware prior to use.

100R does not contain aromatic amines -- therefore it does not require changes to fuel bladders, or tank sealants, or servos, or fabrics, or anti-corrosion coatings, or other types of critical and expensive aircraft parts.

 100R does not contain MMT – therefore it does not require changes to certain fuel system components which are incompatible with Manganese in aircraft.

 100R operates clean in the engine with proprietary detergents and additives – extensive testing proves it does not create sparkplug lead fouling, engine fouling or intake / exhaust valve issues.

 100R qualifies for 100-hour oil change intervals and reduces the frequency for replacing sparkplugs.

 100R eliminates valve seat recession issues and our fuel certification program is designed to confirm 100R meets the expected time-between-overhauls specified by engine OEMs.

 Swift Fuels is pursuing 100R -- a global 100-octane unleaded avgas that combines the following features:

 Low / cost-competitive pricing to 100LL

• Low toxicity / cleanest emissions
• Best operational performance
• Global compatibility with environmental standards

We believe our fuels research, testing and collaboration with FAA and OEM’s will result in the best unleaded avgas solution for the piston fleet on a global scale.

To minimize refueling errors, ALL PISTON AIRCRAFT SHOULD DEMONSTRATE AN FAA-APPROVED FUEL PLACARD SHOWING ALLOWED FUELS. If you have a UL94 FAA-approved aircraft and you do not have any type of fuel placard – then you should get two UL94 placards for $20 (buy it HERE ). OR – Buy a FOREVER Avgas STC for $100 and get 2 placards now and all future Avgas STC’s from Swift Fuels at no extra charge.

Placards should be installed by an FAA-authorized A&P Mechanic who can confirm the integrity of engine and airframe certification in the FAA logbook. Many older aircraft with lower compression engines may have 80/87 type avgas placards next to the fuel port and they define the limitation in the POH. In other cases autogas STC’s may convey similar FAA approvals.

SWIFT FUELS ENDORSES 100% SAFE & COMPLIANT REFUELING PRACTICES:

1 – VERIFY PROPER FUEL PLACARDS ON THE AIRCRAFT

2 – USE THE PROPER FUEL GRADE (e.g. GRADE UL94 vs. GRADE 100LL)

3 – USE ONLY THE COMPATIBLE FUEL NOZZLE (e.g. AVGAS not JET FUEL)

4 – CONFIRM QUESTIONS ON FUEL LIMITATIONS IN YOUR AFM or POH

Airports, FBO’s and Pilots may also refer to these other industry guidelines: NATA MISFUELING PREVENTION PROGRAM

The Swift Fuels 100R Avgas STC is installed on an individual aircraft and covers its eligible airframe and engine configuration. The aircraft is identified in the installation records by its registration number (tail number) and aircraft serial number.

Only one Swift Fuels STC is required for each aircraft—not a separate STC for each installed engine.

Use our search engine here.  Please be aware that once Swift Fuels introduces our high-octane replacement for 100LL, aircraft owners will be required to purchase our Avgas STC from Swift Fuels to fly our high-octane fuel.

So, all customers who buy an STC will be given a FOREVER Avgas STC at no extra charge. The FOREVER Avgas STC entitles the holder to receive ALL future avgas STC's issued by the FAA to Swift Fuels as part of the one simple purchase.

EFFECTIVE NOVEMBER 1, 2026 - ONLINE REQUESTS TO PURCHASE OUR STC FOR CERTIFICATED AIRCRAFT WILL BE FULFILLED WITH 100R PLACARDS. REQUESTS SPECIFICALLY FOR UL94 PLACARDS SHOULD BE HANDLED VIA TELEPHONE OR BY CONTACTING US HERE 

OWNERS OF EXPERIMENTAL / AMATEUR-BUILT (E/AB) AIRCRAFT CAN UTILIZE OUR ONLINE DETERMINATION TOOL - COMING SOON.

For a limited time, Swift Fuels is offering our FOREVER Avgas STC for only $100. This represents a discount of     > 75% from prior avgas STC pricing. Swift Fuels reserves the right to increase prices at any time - so we want to encourage aircraft owners to buy while prices are low.

Customers whose aircraft are compatible with UL94 will receive the UL94 STC along with the FOREVER Avgas STC - at no extra charge. FOREVER Avgas STC holders will receive all future high-octane avgas STC’s issued by the FAA to Swift Fuels that could fully replace 100LL avgas.

Disclaimer: There is no assurance that future avgas STC’s will be issued by the FAA to Swift Fuels, but Swift Fuels is actively working with the FAA towards that objective. This purchase is non-refundable.

UL94 is an ASTM International approved aviation gasoline with a 94+ Motor-Octane Number rating without Tetraethyllead that meets the ASTM D7547 Unleaded Avgas specification. UL94 is also rated as a super-premium ethanol-free auto-gasoline with a 99 anti-knock index octane rating [(R+M)/2] that meets and exceeds the ASTM D4814 autofuel specification.

UL94 Unleaded Avgas has an identical density to 100LL, meaning weight and balance calculations will not change by using UL94. UL94 weighs 5.87 pounds per gallon: identical to 100LL.

Effective March 1st 2024, UL94 is dyed PURPLE as part of a systemic effort by ASTM International to allocate a diversity of fuel colors to the marketplace to improve fuel handling safety. The purple dyed UL94 fuel is identical in certification, specification, and engine performance to the un-dyed UL94 fuel. The change in color is fully intermixable with 100LL and un-dyed UL94.

UL94 Unleaded Avgas, if stored properly, has a very long shelf life – at least as long as 100LL, or even longer. A recent UL94 sample - stored in a sealed airfield tank for over 5 years - was retested in the lab and was still on-spec to ASTM D7547 Grade UL94.

UL94 Unleaded Avgas is sold nationwide and in selected international locations.

UL94 Unleaded Avgas satisfies the minimum octane requirements of over 130,000 aircraft (over 70% of the US piston fleet) as a "Drop-in Ready" Unleaded Avgas. It requires no modifications and no hardware changes.

UL94 has been produced and sold solely by Swift Fuels from our Indiana fuel facility since 2015. All Swift Fuels proprietary avgas products can be licensed for low-cost bulk production from major fuel producers.

If you have questions about this change – please contact Swift Fuels at (765) 464-8336 or contact us here.

Anyone can purchase UL94 by filling out This Order Form. Our team will issue you a quote and once confirmed, we will make arrangements for shipping. UL94 must be stored in an airport tank independently from 100LL, so it is important to have arranged for UL94 avgas tankage in advance of your order. If you need help on this, just let us know by Contacting Us Here.

Yes. UL94 Unleaded Avgas is approved in all Rotax engines:

UL94 is approved on all Rotax engine models which include the following:

The latest Rotax Service Instruction is shown here. Please review all OEM advisories for your aircraft engine.

Yes. There are no mechanical parts, hardware modifications, or adjustments needed to utilize UL94 in an appropriately rated lower compression properly certificated aircraft (approved for ≤ 94-MON Avgas).

All Avgas STC holders must have an FAA-Approved mechanic file FAA Form 337 to validate the applicability of the STC placard on the aircraft. The aircraft owner must also maintain proper regulatory reports and certificates in their aircraft.

Swift Fuels recommends that aircraft owners follow all current engine and airframe OEM operating guidelines. See Lycoming SI-1070 and SL-270 for further details on Lycoming engines. See also Rotax fuel use guidelines; note that Rotax does not recommend the use of 100LL in markets where unleaded avgas is available.

Yes -- assuming that your aircraft is approved to use 94-Motor-Octane avgas. UL94 does not contain toxic tetraethyllead (an octane booster) or ethylene dibromide (a lead scavenger). UL94 eliminates lead-fouled spark-plugs, it eliminates corrosion caused by lead from the oil in the engine and fuel system and it allows pilots flying Lycoming and Rotax engines to save money by increasing their oil-change interval up to 100 hours. UL94 also reduces toxic exhaust emissions.

Swift Fuels recommends that aircraft owners follow all current engine and airframe OEM operating guidelines. See Lycoming SI-1070 and SL-270 for further details on Lycoming engines. See also Rotax fuel use guidelines; note that Rotax does not recommend the use of 100LL in markets where unleaded avgas is available.
 

What is the situation regarding value seat recession at UND?

UND – A unique situation occurred across several weeks in August 2023 at the University of North Dakota flight school when over a dozen Lycoming cylinders first began experiencing valve seat recession. Following weeks of analysis, UND flight school clarified that their flight school pilots operate all flight school aircraft as follow: “full rich at take-off and climb… and Peak EGT at cruise”. Operating at “peak exhaust gas temperatures” is the hottest engine temp on the engine power curve. Over extended periods, these temperatures could potentially damage the exhaust valve assemblies or the valve guides. The valve seat recession reportedly occurred after an average of about 400 hours of flight operation. Operating over hundreds of hours at peak EGT operations is highly unusual according to many US flight schools and generally not advisable according to many IA mechanics. Most flight schools reported to Swift Fuels of flying 50 – 100°F rich of peak. UND said Lycoming replaced the cylinders which were reportedly under warranty. UND said their policy was to fly new piston aircraft equipment precisely so they could utilize the warranty if necessary. Swift Fuels believes that operating aircraft at Peak EGT for sustained periods can run the risk of severely damage engine parts. Also note, when flying Lean of Peak, EGT’s are reduced somewhat, however we understand that Lycoming does not allow aircraft to fly Lean of Peak due to the reduction of fuel flow used for engine cooling. Now that more than one-year has elapsed since this event, no other airport / flight school has experienced or reported this valve seat recession phenomenon. Bottomline, to preserve engine parts – Swift Fuels believes its best to operate your piston aircraft at proper POH settings – preferably rich of peak.

Also be Advised, Swift Fuels 100R unleaded avgas is now commercially available for specified 1,200 engine models and 1,600 aircraft models on a global basis. FAA-approval has already begun, and ASTM International Production Specification (D8603) is completed. 100R has an advanced additive to clean the intake and exhaust valves that includes our proprietary anti-valve-seat recession additive. This is unique in the industry! Our 100R fuel has completed more than 350-hours of high stress FAA engine endurance and durability testing with excellent results using this anti-VSR additive. 100R has completed more combined FAA-certification testing and ASTM International testing than any other unleaded avgas. 

FUEL SPECIFICATIONS – Aviation Gasoline (aka Avgas) is a high octane gasoline designed to meet strict aviation fuel specifications set by ASTM International (e.g. D910, D7547, et al.). Auto Gasoline (aka Autofuel or Autogas or Mogas) is any form of on-road or off-road transportation fuel that meets the ASTM International D4814 gasoline standard or EN 228. Autogas in the US may contain up to 10-15% ethanol depending upon its intended use for consumption. E0 and E85 grades are also sold in some US market locations. Note that international fuel standards for certain fuels vary by country.

The key differences in the performance characteristics of Avgas vs. Autogas are outlined below:

a) FUEL CHEMISTRY - UL94 Unleaded Avgas is made from higher quality, lower boiling hydrocarbon components resulting in virtually no sparkplug deposits, fewer exhaust contaminates, and lower aromatics content vs. Autogas. All Swift Fuels unleaded avgas products meet this same strict premium quality standard. Autogas is made with many more higher boiling aromatic compounds which, when used in an aircraft, are inadvertently released into the atmosphere without catalytic converters to cleanse the byproducts of combustion from a piston engine.

b) OCTANE - avgas has a much higher octane vs. the 87 or 91 (R+M)/2 octane rating of autogas (e.g. UL94 avgas equates to a minimum 97 octane using the (R+M)/2 autogas octane rating),

c) SHELF LIFE - avgas components have very few gum forming compounds, but autogas specifications are less strict allowing for more chemical compounds which tend to oxidize and form much larger amounts of gums after about 60-days of storage,

d) VAPOR PRESSURE - avgas has a low vapor pressure (5.5 to 7.1 psi), where autogas RVP is higher (7.5 to 15 psi in certain states at certain times) which can lead to vapor lock issues in some conditions,

e) SUPPLY CHAIN - avgas is managed by strict fuel handling standards, guidelines and insurance documentation per batch, whereas autogas is far less strict (depending upon where its purchased). Note that autogas in the US may contain up to 10-15% ethanol. Some gas stations may also sell an “off-road” variation of autogas with no ethanol called recreational fuel. Be advised that some recreational autogas may inadvertently contain ethanol. Ethanol use above 1% in aircraft is not recommended by FAA or Lycoming. Finally, please be advised that autogas may be sold to pilots at retail gas stations without a Certificate of Analysis and it may not be insured for aviation use.

On a fleetwide basis – No.

In select aircraft with robust safeguards – Yes – but with clear, formally trackable caveats.
 

What are Aromatic Amines?

• Aromatic Amines are intermediate chemicals most often used as a precursor to pesticides, pharmaceuticals, and dyes.
• Aromatic Amines are different from aromatic hydrocarbons like toluene (which is common in gasoline) or xylene (often used in petrochemicals).
• Aromatic Amines are derivatives of ammonia (-NH3) typically where an aryl group is substituted for a hydrogen atom forming an amino group (-NH2) bonded to a benzene ring
• Aromatic Amines are chemical compounds with about 5 to 10 times higher toxicity levels than typical hydrocarbon gasoline compounds.
• Aromatic Amines have been known since 1919 to enhance octane levels in gasoline piston engines, but with serious commercialization challenges.
   

Why does Swift Fuels not use Aromatic Amines as an octane booster in avgas?

• 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.

Are they the same as “Nitro-Amines”?
No. Aromatic Amines are not “Nitro-amines”. Nitro-amines are organic compounds containing a nitro group (-NO2) bonded to an amine (N), i.e. not bonded to an aromatic (benzene ring). More importantly, Nitro-amines are not used as octane boosters in fuels.

Are they the same as detergents in gasoline?
No. Aromatic Amines are also distinctly different from many other “non-aromatic” Amines used since the 1970’s as detergents in gasoline. For example a commonly used detergent called Polyether Amine (PEA) is not an Aromatic Amine. These “non-aromatic” Amines used in gasoline are lower toxicity, safer to the public, and are only used at parts-per-million (ppm) levels to help cleanse engines using auto gasoline (e.g. ~ 1000 ppm, or about 0.1% of the fuel ).

Are they an octane booster?
Yes. Aromatic Amines are now being considered as octane boosters in avgas because they can increase the anti-knocking effects of gasoline in higher compression engines. However, this requires much more volume than gasoline detergents in order to boost octane (e.g. ~ 20,000 – 150,000 ppm of the fuel ). In this ratio – Aromatic Amines are very aggressive on the entire aircraft fuel system and may in some cases erode, soften, destroy or weaken critical aircraft fuel system components. In addition, Aromatic Amines upon combustion with air will emit about 5 times more Nitric Oxides (NOx) than traditional aviation fuels. Note that nitrogen dioxide (NO2) combustion emissions are an EPA Criteria Air Pollutant (as is Lead).

Which Aromatic Amines are being considered?
For several years, the avgas research and development team of Swift Fuels has studied the pros and cons of using a wide array of Aromatic Amines in avgas on a global basis. Our proprietary fuels research has specifically addressed the following Aromatic Amines which are known to boost octane ratings:

• Aniline (CAS# 62-53-3)
• m-toluidine (CAS# 108-44-1)
• p-toluidine (CAS# 106-49-0)
• N-methyl-m-toluidine (CAS# 696-44-6)
• N-methyl-p-toluidine (CAS# 623-08-5)
• Cumidine (CAS# 99-88-7)
• Mixed xylidine (CAS# 1300-73-8)

Can pilot’s mix G100UL avgas with any Swift Fuels avgas product in an aircraft? 

NO. This is restricted by Swift Fuels STC. 

Swift Fuels avgas STC documentation restricts the use of G100UL in any aircraft that uses 100R or UL94 due to G100UL’s lack of ASTM production specification approval and concern from market reports notably in California since November 2024 that paint stripping and aircraft fuel system damage was caused by highly aggressive aromatic amines found in G100UL. 

Our research primarily considered toxicity issues, NOx and material compatibility issues - because the octane boosting features of these Aromatic Amines are well known since the 1920’s. Key elements of our research on Aromatic Amines has been reported to ASTM International, the Coordinating Research Council, the American Petroleum Institute and to the FAA over the past 5 – 7 years. The FAA shared highlights of various of these preliminary research findings with the public and with the National Academy of Sciences, Engineering and Medicine in Washington DC in 2019.

None of the Aromatic Amines shown herein are used as octane boosters in any Swift Fuels Unleaded Avgas products primarily due to toxicity, NOx, and material compatibility concerns that can impact flight safety when used in piston aircraft.

For more information about the health effects of these chemicals, we recommended accessing the European Chemical Agency (ECHA) system here to inquire on each Aromatic Amine compound noted above. Note: These chemicals are strictly controlled in Europe but are rarely sold commercially in the USA since they are often precursors to other downstream chemicals. Thus, detailed US toxicity data is limited.

No. 

G100UL must not be used at this time in aircraft approved for a Swift Fuels STC, and furthermore G100UL must not be intermixed with any Swift Fuels’ avgas product in any aircraft. 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, fabrics, composite materials, and various elastomeric parts in aircraft fuels systems. Swift Fuels does not authorize the use of G100UL in any Swift Fuels STC-certified aircraft, and therefore Swift Fuels will not indemnify any contractual claim, physical harm, tort, property damage or any other liability arising from the use of G100UL. Swift Fuels has actively reported the dangers of aromatics amines privately tested in avgas to FAA, ASTM International, CRC, National Academy of Science, API, and others for the past 6 years. Swift Fuels has also notified airports and pilots in online safety forums of the dangers of aromatic amines. Pilots who elect to intermix G100UL considering these warnings are operating at their own risk.

Please be advised that Cirrus Aircraft has issued a Service Advisory warning to pilots - SA24-14R1 - describing serious material compatibility concerns involving fuel tank sealants. See the Service Advisory here. Accordingly, Cirrus does not approve the use of G100UL fuel in any Cirrus SR Series airplanes at this time. Also be advised that G100UL may not be approved for use by other aircraft manufacturers and therefore its use may not be covered by OEM engine or airframe warranties. Consult your OEM.

Recent Incidents Involving The Use of G100UL Have Been Reported In The Marketplace:

• Pilot/Mechanic at Reid Hillview - Oshkosh 2026 Update
• Summary of Test Results - July '26 at Oshkosh
• Pilot/Mechanic at Reid Hillview Update Feb ’26 
• Pilot/Mechanic at Reid Hillview Update Sep ’25
• Cessna 421 Proof of Loss Caused by G100UL
• Cirrus SR22T Report of Damage at RHV Jan ’25
• Pilot/Mechanic at Reid Hillview Update Feb ’25
• Pilot/Mechanic at Reid Hillview Update Jan ’25
• Pilot/Mechanic at Reid Hillview Dec ’24
• Juan Browne (Blancolirio) Short on G100UL Apr ’25
• Barron at Oshkosh Sept ’24

Pilot reports of fuel leaks, paint staining, and paint stripping are early warning signs of the dangers caused by the aggressive solvent: meta-toluidine found in G100UL. Consider that over 50% of the US piston fleet uses epoxy as a protective coating on aluminum fuel tanks. In some cases, sealants are then adhered to these epoxy surfaces. Over time, the epoxy can strip away, and the sealants can be disturbed, debonded or cracked as meta-toluidine reacts with their chemistry. Such damage can ultimately impact fuel flow in the fuel tank. These early incidents are the “canaries in the coal mine”... i.e., any early warning to the industry of what could happen on a larger scale. Swift Fuels believes these early incidents all point to what could become catastrophic flight safety risks.

Finally, be advised that to-date, G100UL has failed to earn an ASTM International Production Specification - a voluntary industry consensus specification required by EPA regulated fuels - that is called for by the aviation marketplace for all aviation fuels including Avgas, Autogas, Jet Fuel and SAF. The process to earn such an ASTM specification includes a rigorous set of ASTM tests and vetting procedures on a global basis designed to uncover the challenging defects of any new fuel product before entering the marketplace. According to their website, G100UL is not actively participating in the ASTM International process. On August 22, 2023, the Washington Post quoted George Braly the co-founder of General Aviation Modifications as saying, “it could take years for his company to secure such an approval”.

YES Absolutely. If your aircraft (engine and airframe or rotorcraft) is approved to use Swift Fuels 100R or UL94, then you are fully allowed to intermix them with 100LL at any ratio. For the past 9 years, UL94 has been FAA-approved via STC, it has a full ASTM International Production Specification (D7547), and it has received many OEM endorsements. Please recognize that the benefits of using our unleaded fuel (no fouling, clean exhaust, cleaner oil, etc.) are primarily realized when 100% UL94 Avgas is in use. Please also check engine OEM recommendations of the use of synthetic (additized) engine oils outlined on our website. 100R and UL94 unleaded avgas are now approved for over 65% of the certificated US piston fleet which further represents at least 60% of the avgas consumption on a US-wide basis.  

For up-to-date intermixing information, see our Service Instruction, SI-1.

Together, they both play a vital role for commercializing fuel used in all FAA-certificated aircraft, and we also extend our ASTM research and testing work to address Experimental and other non-certificated aircraft as well.

FAA’s role in Certification: According to Title 14 CFR parts 33, 23, and 27 (among others), new unleaded fuels in the US marketplace must have FAA-certified design approval for the appropriate engines, airframes, and rotorcraft intending to use the fuel. This FAA certification approval can come via a TC, STC or PAFI-type approval for a defined aviation fuel. To our knowledge the FAA is actively involved in all these areas of certification work for the 3 fuels in the EAGLE program as outlined in the Reauthorization Act of 2024. Swift Fuels has reported that our internal team working on our 100R unleaded avgas STC program may merge with the PAFI program at some point in the months ahead after a critical majority of approved models are in place in our STC / AML program.

ASTM’s role in Fuel Standards: FAA statutory requirements, airworthiness directives, guidance documents and advisories also describe the use of voluntary industry consensus standards for avgas outside of FAA (e.g. ASTM International) to augment and reinforce the FAA’s Title 14 regulations. Industry consensus standards to increase and reinforce FAA certification efforts are called out in the FAA Reauthorization Act of 2024, OMB A-119, and AC20-24-D, among many other references. These industry standards also target fuel production, quality control, proper handling, and global supply chain aspects of the fuel – particularly upstream of the aircraft.

Here’s an Example of the Relationship: FAA’s 14 CFR Part 23 airframe regulations provide a thorough criteria of airworthiness standards and flight operations; however, these federal regulations tend to offer only high-level guidance on the importance of aircraft material compatibility. For example, in Section 23.2260 – the regulations describe materials and processes that provide clear guidance but only make vague references to the type of materials used in aircraft. To supplement this, ASTM International working with FAA, Industry and aviation OEMs has developed a comprehensive industry consensus standard for new aviation gasolines over the past 20 years called D7826 which thoroughly outlines numerous fit-for-purpose test requirements and specific aircraft and engine materials required by global industry participants to test some 32 metals, and over 50 non-metallic parts including fuel bladders, O-rings, diaphragms, anti-corrosion paint, epoxy-liner coatings, tank sealants, fabrics, hoses, composites, and many more items. Swift Fuels’ FAA STC program began testing all these ASTM D7826 specified items during PAFI and from the beginning of our current 100R STC program, because the FAA part 23 requirements were known by industry to need additional clarity and augmentation on many of these critical points. Swift Fuels has reported all this information to FAA and to ASTM International and other industry groups on many of our test results pertaining to items since 2018. ASTM D7826 guidance has been used by all PAFI aviation fuels since 2014 and continues to apply to all aviation gasoline products.

Can Someone Opt-Out of ASTM: No avgas fuel producer should opt-out of ASTM International and its deep collaboration with industry and OEM representatives. However, it is our understanding that to date, the producers of G100UL have not followed and will not pursue an ASTM International industry consensus fuel specification. Swift Fuels believes this omission of ASTM collaboration by the producers of G100UL (i.e., avoiding development of a full industry consensus fuel specification) is a major defect for G100UL fuel offering that should give the aviation industry and piston aviation pilot’s serious concerns about aircraft reliability and ultimately flight safety. Furthermore, our FAA-approved Swift Fuels’ STCs do not allow the use of G100UL to be mixed with any of our fuel products due to the detrimental behaviors we believe are caused by 3+% meta-toluidine used in G100UL that has been reported to disturb fuel systems, impact aircraft performance, and disrupt supply chain assets. Swift Fuels has repeatedly reported these matters to industry based on our own proprietary fuel intermixability testing using ASTM methods that highlight these concerns. Accordingly, there is no indemnification to any third party by Swift Fuels if harm or destructive compatibility problems occur from using G100UL with our marketed unleaded fuel(s). Swift Fuels will monitor and continue to test alternative fuel products to evaluate how these new or changing products from 3rd parties may affect our approved fuels in the marketplace.

Bottomline: Aviation stakeholders in the US collectively agree that FAA Certifications coupled with ASTM International Fuel Specifications are the minimum industry standard for providing commercially available avgas.

YES - 100R complies with ASTM International Specification D8603, which can be purchased from ASTM here.

You can find a comprehensive list of engines FAA-approved to run on 100R unleaded avgas on our Approved Model List (AML) STC here or you can search for a specific engine model here.

Lycoming publishes Service Instruction SI-1070 which shows the engines currently approved for UL94 Unleaded Avgas, compliant with ASTM D7547. These are summarized here. See below ---

See the full Service Instruction here

Refer to the latest versions of SI-1070 and your engine Type Certificate Data Sheet for any special OEM stipulations in using UL94 with Lycoming engines.

Refer to the latest versions of SI-1070 and your engine Type Certificate Data Sheet for any special OEM stipulations in using UL94 with Lycoming engines.

Yes – for Cessna 172 models -I, -K, -L, -M, and -P with a Lycoming O-360-A4M engine installed by Penn Yan Aero’s certified team using their STC SA703GL. This configuration is FAA-approved to use UL94 Unleaded Avgas. Please see their letter of confirmation below. 

Lycoming’s SI-1070 requires one of the following additized oils (or additive LW-16702) when using unleaded avgas. These oils are also highly recommended for use with 100LL as an anti-scuffing agent to protect the cam shaft in certain engines.

According to FAA SAIB NE-06-31R6, the following oils are may be used as an anti-scuffing agent for any appropriate piston aircraft.

See the full SAIB here

Continental publishes fuel requirements for each engine model on their Type Certificate Data Sheets. These are summarized here. See Chart below ---

Refer to the latest version of your engine Type Certificate Data Sheet for any special OEM stipulations in using UL94 with Continental engines.

No. A twin-engine aircraft requires only one Swift Fuels Avgas STC. The single STC installation covers the aircraft and both installed engines, provided the airframe and each engine model are included within the applicable Swift Fuels FAA-approved eligibility lists.

You can find a comprehensive list of airframes that are FAA-approved to run on 100R unleaded avgas on our Approved Model List (AML) STC here or you can search for a specific airframe model here.

Yes! According to SEB-28-04R1, the following engines and aircraft have been approved by Textron Aviation to use UL94 Unleaded Avgas with the applicable fuel placards installed.

See Textron Aviation's Service Bulletin here.

Textron Aviation typically sells the applicable placards for $72 and $83 each at their Authorized Service Centers. Pilots must follow all the instructions stipulated in Textron's Service Bulletin.

Alternatively, you may purchase a 100R or UL94 STC with 2 fuel placards for $100 from Swift Fuels here. This purchase comes with a Forever Avgas STC at no extra charge. Replacement placards for our issued Avgas STC’s are only $20/pair here.

Yes, we do insist - It is all about flight safety! Pilots know that alternations (including a change to an STC-approved fuel) requires an FAA sign-off and the application of a fuelplacard. Swift Fuels values the role of the FAA-authorized signers – typically an A&P Mechanic and in IA (Inspection Authorized mechanic) to approve the form. Other FAA-authorized signers may also certify the “alteration”. This allows 2-pairs of eyes to confirm the airframe certificates and engine certificates are in alignment for our unleaded fuels program. We believe this helps prevent pilot misfuelling errors – which is a #1 priority of our aviation fuels’ business. Swift Fuels has developed methods to streamline the preparation of the Form 337 – to minimize and focus the effort for FAA-approved mechanics to engage in this brief but critical review process. Our STC offers pilots the option to PRINT an AUTO-POPULATED Form 337 for your mechanic from our proprietary Swift Fuels STC website– to save pilots time and money!

See below the typical signature block on a Form 337 - as there are various authorized signers allowed. Notice that in section 6. B. a US Certified Mechanic (aka – an A&P Mechanic who holds an Airframe and Powerplant (A&P) certificate) – This is by far the most common approver, but as you can see, others may also approve. Notice under section 7. an IA (aka Inspection Authorized mechanic) or similar FAA-authorized approver must also oversee the 337 entry for the aircraft’s Return to Service. In some cases – the A&P Mechanic may also be authorized as the IA or other authorized approver.

For questions about the Federal Regulations pertaining to the form 337, refer to AC 43.9-1G here.

A copy of the standard FAA Form 337 can be found here.

Yes. All FAA-certificated piston aircraft will be required to install an FAA-Approved STC on their aircraft to utilize Swift Fuels 100 Octane Unleaded Avgas. Swift Fuels will use the FAA's STC program for managing the fleetwide-deployment of our 100-octane avgas.

In order to manage the fleetwide deployment of our 100-octane Avgas program to every piston aircraft, Swift Fuels has introduced a pre-paid STC certificate called a FOREVER Avgas STC. The FOREVER Avgas STC certificate can be purchased here

The purchaser will receive:

a)  Swift Fuels UL94 Avgas STC placards (if your engine/aircraft combination is UL94 eligible),

b) an AVGAS FOREVER STC Certificate allowing the holder to receive all future avgas STC’s (placards, license, and forms) issued by FAA to Swift Fuels at no extra cost,

c) Instructions for accessing a private weblink allowing the purchaser to access Swift Fuels’ private database to enter secure information and generate a set of regulatory reports to complete the local STC process.  STC standard reports in the US include the FAA Form 337 (to be executed by an approved aircraft mechanic), Instructions for Continued Airwothiness (ICA), Flight Manual Supplement (FMS), etc. and may vary by type of airframe or engine.

d) Private access to Swift Fuels online forum containing semi-annual newsletters, product updates, and merchandise.

No. A new STC purchase is not required solely because an engine is replaced or its serial number changes.

This includes a factory-new, factory-remanufactured, or eligible exchange engine, provided the replacement engine conforms to the same approved engine model and configuration covered by the STC.

The replacement engine must be properly installed and documented, and the aircraft owner should update the engine information in the Swift Fuels customer database. If the replacement changes the engine model or approved configuration, eligibility must be confirmed before using Swift Fuels 100R Avgas.

With this purchase, you will receive the AVGAS FOREVER STC certificate in the mail.

Customers with airframes/engines that require a UL94 STC, once registered in our Swift Fuels customer database, will be given immediate access to our UL94 STC installation package and will also be entitled to all future Swift Fuels Avgas STC’s.

Customers whose aircraft have higher-compression engines will receive instructions in the mail on how to register their aircraft information into our Swift Fuels database. In either case, when future Avgas STC's are issued to Swift Fuels from the FAA, all registered customers in our customer database will be contacted by Swift Fuels representatives to receive your “newly-issued” STC placards, STC license and appropriate documentation at that time.

It is important to follow the instructions on the STC certificate and register your customer and aircraft information into the Swift Fuels database. Please keep your registration information up-to-date. Contact Swift Fuels if you cannot locate your registration information.

The Forever Avgas STC Certificate should follow the aircraft. If you sell the aircraft, make sure to provide the new owner with that aircraft’s private Forever Avgas STC registration certificate. The Swift Fuels database is tied to a secure identification number (shown on the Forever STC registration certificate) that is recorded against each unique aircraft serial number.

If you buy a Forever Avgas STC Certificate prior to owning a particular aircraft, you can hold onto the certificate until you take possession of the new aircraft and then register it onto the Swift Fuels database online.

Each Forever Avgas STC certificate is tied to only one aircraft. Each registration card provides all the private instructions needed to record the aircraft into the Swift Fuels Forever Avgas STC system.

The FOREVER Avgas STC is a certificate that allows the holder to receive all current and any future Avgas STC's issued to Swift Fuels by the FAA for a specific engine and airframe combination.

Purchasing the Swift Fuels' FOREVER Avgas STC certificate allows pilots to register their aircraft ONCE in the Swift Fuels database, then all applicable Avgas STC documentation (e.g. STC placards, STC license, FAA forms) will be provided directly by Swift Fuels to the FOREVER STC holder at no extra charge - Forever!

If you purchase a FOREVER Avgas STC, you will automatically receive a UL94 Avgas STC at no extra charge if your aircraft is authorized to utilize UL94.

Once approved, all FAA-certificated aircraft will be required to have a Swift Fuels STC to utilize our 100-octane avgas to replace 100LL - so the FOREVER Avgas STC is our company's way to manage the Fleetwide Approval program by engine / airframe for our fuel.

Please support Swift Fuels and purchase a FOREVER Avgas STC today!

Yes, as necessary. Swift Fuels is highly focused on supporting “Operational Excellence” in the quality of local fuel handling, managing fuel storage tanks and trucks at airfields/FBOs, and in managing aircraft refueling safety. If we can – we will assist local airfields/FBO’s in identifying technical expertise and/or resources that may be useful. We are happy to help any stakeholder to achieve safe avgas refueling operations - nationwide.

Fuel Handling – all Swift Fuels unleaded avgas products comply with ASTM International fuel specifications which tie to universally approved ASTM test methods. Our fuels have a proper Certificate of Analysis which reconciles to these approved methods. We also consult with airfields on the use of appropriate fuel handling methods. We collaborate with various aviation industry teams (e.g. NATA) to convey safe fuels handling procedures to the industry as it relates to handling unleaded avgas.
 

Tankage / Fuel Storage – Swift Fuels has strict requirements to confirm that airfield tankage is appropriately managed. We provide a series of checklists to each airfield prior to receiving our unleaded fuel. We recommend the use of UL142 double-walled Aboveground Storage Tanks (AST) along with appropriate containment and up-to-date Spill Prevention and Countermeasures Control SPCC documentation on-site with local fire marshal endorsement of the fuel operations. Airfields with Underground Storage Tanks (UST) are subject to a higher scrutiny of ongoing monitoring and controls and must demonstrate their compliance with EPA and state-specific UST standards. Airfields that are subject to LUST compliance regulations are advised to take active steps to reengineer their airfield tankage to an up-to-date configuration and thereby eliminate unnecessary taxes, fees, and fines. Swift Fuels is available to consult with any airfield on the available options to upgrade their fuel storage operations. Contact Swift Fuels here.

Aircraft Refueling – To help ensure pilot safety, we advise all aircraft owners / pilots to display a fuel placard on their aircraft that highlights the applicable fuel for use in their aircraft. This along with any supplemental information in your Flight manual Supplement are critical information for the aircraft operator. This information is an integral part of our Swift Fuels STC program. See related question in our FAQ list.

No, not according to our current Swift Fuels deployment plan. Our 100-octane unleaded avgas will be fully commingable with 100LL. This means that it can be stored in the same airport tank as 100LL and commingled into the aircraft fuel tanks with 100LL at any ratio. Our avgas deployment plan anticipates that all Swift Fuels products can work effectively with 100LL.

Note that UL94 can also be fully commingled in lower compression aircraft -- however UL94 requires a separate airport fuel tank (Currently, airports serving UL94 must store it separately from 100LL as 100LL must be kept on hand in a separate storage tank for use for higher octane aircraft).

No, not at this time. Sustainable Aviation Fuel tax credits currently offer fuel blenders a tax incentive that applies to various renewable fuels derived from biomass including biodiesel and renewable diesel – particularly those meeting ASTM D7566 jet fuel specifications - on the premise they offer substantially lower carbon intensity indices. This legislation is currently not applicable to aviation gasoline. Swift Fuels is actively engaged in advocacy work with legislative consultants to get our 100R (10% renewable) unleaded avgas eligible to earn some type of Blenders Tax Credit (BTC) for our 100R unleaded avgas during the transition period to unleaded avgas. 100R avgas eliminates toxic lead emissions and has ultralow NOx emissions – it is the cleanest burning unleaded avgas product available to meet the 100-octane requirements of the global piston-engine fleet based upon our proprietary research. The renewable component of 100R is derived from processing ethanol into an oxygenate that is safe for aircraft use and results in more complete combustion of all fuel components. Swift Fuels believes these factors provide a strong basis for an SAF BTC equivalency for 100R.

Based upon our Swift Fuels proprietary lab testing, other octane boosters which may also be available to replace tetraethyllead, however their emissions may not meet the concept of equivalency to the SAF:

• Aromatic Amines tend to produce 5 to 10 times more NOx emissions – an EPA criteria pollutant.
• MMT is an organometallic compound in many ways similar to tetraethyllead blended in 100LL avgas.

These tax credits are typically set with legislated term limitations and may not justify a long-term structural discount to consumers.

The Center for Disease Control (CDC) provides a comprehensive array of medical recommendations for monitoring blood LEAD levels particularly in young children. Check with your pediatrician. 

Prior to 2012, the CDC action limit (“level of concern”) on LEAD exposure in children was generally 10 micrograms per deciliter based upon their particular blood test protocol. In 2012, the CDC action limit (renamed the “Blood Level Reference Value”) was lowered to 5 micrograms per deciliter. At that time, the EPA reported that only 2.5% of all children tested between ages of 1 to 5 years old had blood LEAD levels above 5 micrograms per deciliter - a marked improvement over prior years. Then in 2021, the CDC Blood Level Reference Value for LEAD was lowered again to 3.5 micrograms per deciliter. Obviously, the new lower LEAD blood level reference value of 3.5 μg/dL means that more children could be identified as having lead exposure allowing parents, doctors, public health officials, and communities to act earlier to reduce the child’s future exposure to lead.

Swift Fuels recommends parents proactively monitor their children’s exposure to LEAD, particularly if you are in an environment where LEAD exposure is likely. The CDC’s identifies the following considerations for possible sources of LEAD to avoid:
 

• Homes built prior to 1978 probably contain lead-based paint (after which LEAD-based paints were banned). When the old paint peels and cracks, it makes lead dust. Children can be exposed to lead when they swallow or breathe in lead dust.
• Certain water pipes may contain LEAD.
• LEAD can be found in some products such as toys and jewelry.
• LEAD is sometimes found in candies or traditional home remedies.
• Certain jobs and hobbies involve working with LEAD-based products, like stain glass work, and may cause parents to bring LEAD into the home.
• Children who live near airports may be exposed to LEAD in air and soil from the combustion of 100LL (LEADED) aviation gasoline.

YES - We hired a team of independent scientific toxicologists to evaluate the health effects of our fuels vs. 100LL. All of these results were supplied to the FAA and ASTM International for confirmation that our fuels pose less of an environmental concern than 100LL. For further infomration, review our SDS's for 100R and UL94 here.

No. There are various California restrictions pertaining to Lead, oxygenates, alcohols, and other compounds in autogas, but these restrictions do not apply to aviation gasoline.

In California, an aircraft is not registered as a “motor vehicle” in the state because aircraft registrations and pilot certifications are managed by FAA at a federal level.

FYI – US Code defines motor vehicles in Title 49 U.S. Code § 30101 - a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways

CCR Title 13 § 2253.4 – this law restricts “motor vehicles” operating in California (i.e., vehicles travelling on roads and highways) from using any “lead” in gasoline

CCR Title 18 § 1101 defines various aviation gasoline fuels used for aircraft use

California Air Resources Board - Aviation gasoline emissions are currently exempt from EPA’s oversight of lead emissions.

Prop 65 - California's EPA (OEHHA) allows the use of ETBE in California

California Revenue & Tax Code § 7306 – All aviation gasoline sales are levied a California state excise tax at 18.6 cents per gallon