Frequently Asked Questions

What is UL94 Unleaded Avgas?

UL94 is a 94+ Motor-Octane aviation gasoline 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 octane (R+M)/2 rating 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 5.9 pounds per gallon: identical to 100LL.

UL94 Unleaded Avgas is currently colored clear (“water white” as defined by ASTM International) and smells like a mild version of 100LL, which is less pungent than Autogas which typically has about 25 – 50% aromatics.

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 125,000 aircraft (66% 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.

How can my airfield buy UL94 Unleaded Avgas?

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.

Do I need a UL94 Avgas STC for my airplane?

You can search our online database  to confirm eligibility. UL94 STC’s are sold online  by Swift Fuels and buyers automatically receive our FOREVER Avgas STC Certificate at no extra charge. Our FOREVER Avgas STC Certificate will entitle the holder to receive all future Avgas STC's issued by the FAA to Swift Fuels at no extra charge.

Please read the details related to this FOREVER STC offering carefully. There are no guarantees related to any future FAA actions and there are no refunds related to this offering.

Do I need to have a UL94 Fuel Placard to use UL94 Avgas?

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.







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

Why does Swift Fuels insist on using the FAA’s Form 337 and FAA-authorized fuel placards for your unleaded fuel program?


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.


Sample 337


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.

Intermixability: If my aircraft/engine is STC approved for UL94 unleaded avgas, can I intermix with 100LL ?

YES Absolutely. If your aircraft (engine and airframe or rotorcraft) is approved to use Swift Fuels UL94, then you are fully allowed to intermix UL94 with 100LL at any ratio. For the past 7 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. UL94 unleaded avgas is now approved for over 70% of the US piston fleet -- including the recent addition of 15 Continental engine models previously approved for 91/96 avgas.

If my aircraft/engine is approved for UL94 unleaded avgas.. can I intermix with GAMI’s G100UL fuel?

No - this is not advisable at this time. Swift Fuels has not seen the final FAA-Approved fuel blends of G100UL and there is no approved ASTM fuel specification. This is not normal protocol. Swift Fuels accepts the principle that all “Qualified” aviation gasolines sold in the US market and endorsed by OEM’s must have an ASTM Production Specification. Be advised that across the nation: 100LL Avgas, UL94 Avgas, Jet Fuel, SAF Jet Fuel, and Autogas all have ASTM Production Specifications. Swift Fuels believes the FAA does not have regulatory authority to waive-off industry and/or disallow the need for an ASTM Production Specification for any commercially available aviation fuel. It is Swift Fuels’ understanding that - according to the GAMI website and video reports – G100UL does not have an ASTM Production Specification, and does not plan to have one. Accordingly, at this time we do not advise the commercial blending of G100UL fuel in any aircraft fuel system using Swift Fuels’ products until its fuel safety can be confirmed. As these facts might change, we will be monitoring these matters closely and will be updating our website as appropriate to inform our stakeholders.

Which Lycoming engines are approved to use UL94 Unleaded Avgas?

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.

Has Textron Aviation endorsed the use of UL94 Unleaded Avgas?

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 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.

What type of engine oil do I need to operate UL94 unleaded avgas in my aircraft?

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



Which Continental Motors engines are approved for UL94 Unleaded Avgas?

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.


Does my Penn Yan Aero engine installation qualify for using UL94 avgas? 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. ---



Is Swift Fuels planning to deploy a 100-Motor-Octane avgas for fleetwide replacement for 100LL? If so, when?

Yes. Swift Fuels has been conducting extensive scientific research, fuel testing, engine testing, and flight testing on all viable high-octane alternatives to replace 100LL since 2012. Our #1 candidate to fully replace 100LL is a premium 100-octane unleaded avgas product that is already patented and is currently undergoing testing and certification with the FAA.

Swift Fuels elected to discontinue our involvement in the FAA-managed PAFI fuel test program in August 2018, preferring instead to manage our unleaded fuels testing program in-house while still working closely with OEM's and the FAA Fuels Program Office. We expect to begin the roll-out of our high-octane unleaded fuel within months from now -- and we hope to have a fleetwide solution ready to deploy for North America by the end of 2025.

Will Swift Fuels’ new 100R unleaded avgas product have an ASTM Production Specification when it comes to market?


YES - Absolutely. Swift Fuels has an active ASTM 100R Task Force now and has been compiling ASTM test results to support our ASTM production specification in preparation for our 100R market entry in the months ahead. ASTM International is a global team of petroleum industry technical experts coupled with OEM’s and FAA personnel who evaluate the operational characteristics of all market-ready fuels. ASTM International must approve all market-ready aviation gasoline products via a formal production specification (i.e. consistent with the approach for D910 and D7547 for aviation gasoline). ASTM approved test methods are used to validate each of the itemized components, performance characteristics and fuel properties (e.g. motor octane, vapor pressure, etc.) of any given fuel’s production specification. ASTM performance metrics are measured on every aviation gasoline fuel batch produced, transported, received/handled and sold in the US marketplace, setting a high quality standard on aviation gasoline. 100R intermixability -- we expect that all 100R approved engine/aircraft will be able to intermix 100LL at any ratio.

Will I need a separate tank at my airport for your 100-octane avgas to fully replace 100LL?

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).

Will I need an STC to use Swift Fuels' 100-Motor-Octane product?

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

What is a FOREVER avgas STC?

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!

If I buy a FOREVER Avgas STC certificate, what all comes with my purchase?

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.

How much does a FOREVER Avgas STC certificate cost?

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 - which we hope to achieve by end of 2023. This purchase is non-refundable.

So if I get the AVGAS FOREVER STC Certificate, when will I get the STC?

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.

How do I know if I need a UL94 STC?

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 a UL94 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.

Can I commingle UL94 with 100LL in my aircraft?

Yes, commingling of 100LL and UL94 unleaded avgas in the wing tank of an aircraft is 100% safe – as long as the aircraft and engine are approved for the use of UL94. In fact, over 66% of the US piston fleet is FAA certificated to use UL94 unleaded avgas because the engine/airframes are rated at min 94 octane or lower... Therefore, they can all use UL94 avgas since its 94-motor octane fuel value is higher than their minimum required octane levels. This just means 100LL has more octane -- it is rated as 6+ motor octane numbers more UL94. It has more octane than what “UL94-approved” aircraft actually need.

UL94 avgas has the same chemistry as 100LL --- but without the use of tetraethyllead (LEAD) or its equally toxic scavenger ethylene dibromide... So – hypothetically if an aircraft had a half-full tank of 100LL and then filled the remainder with UL94, then the aircraft tank would have about 97+ motor octane gasoline (commingled).. But given that the aircraft is rated for 94 motor octane and lower (some are min 91, some are min 80/87), the excess octane is of no added benefit...

FBO’s who sell 100LL to higher compression aircraft must keep UL94 in separate storage tanks – to prevent misfuelling an aircraft that MUST only use 100-octane avgas. Aircraft/engines that are approved only for 100-octane avgas must not use UL94 because the detonation suppression of this fuel is not sufficient in these engines.

Is UL94 Avgas “drop-in-ready”?

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.

Is Swift Fuels’ 100-octane Avgas (100R) “Drop-In-Ready” Fleetwide?

YES - Our 100R unleaded avgas product is designed to support 100% of the US and global piston aircraft fleet’s fuel requirements without modifying aircraft hardware.

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 – therefore it does not create sparkplug or engine fouling.

100R qualifies for 100-hour oil change intervals. 100R does not impact valve seat recession and our fuel certification program is designed to confirm 100R meets the expected time-between-overhauls specified by engine OEMs.

100R is drop-in ready across the global piston fleet.

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.
Is UL94 better for my aircraft than 100LL?

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.

Is UL94 approved for all ROTAX engines?

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


UL94 is approved on all Rotax engine models which include the following:
  • 912 A/F/UL
  • 912 S/ULS
  • 914 F/UL
  • 912 iSc/iS Sport
  • 915 iSc/iS A
  • 915 iSc/iS C24
  • 916 iSc B

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

What is the difference between Avgas and Autogas?

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.

What if I buy a new airplane or sell my existing airplane? Do I keep my Forever STC?

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.

How do parent’s know if their children are being wrongly exposed to LEAD poisoning? If exposed, what actions should be taken?

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. See the CDC link here

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.

Finally, to reduce the health risk of LEAD exposure, here are five CDC suggestions to improve children’s health.

Does Swift Fuels unleaded avgas earn a Sustainable Aviation Fuel (SAF) tax credit?

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.

Is Swift Fuels considering using ETBE in Unleaded Avgas?

YES – Swift Fuels proprietary research and testing on ETBE is active and ongoing. ETBE is also being evaluated as an avgas octane booster by industry, ASTM International, and FAA at this time.

ETBE is a high-octane oxygenate with many favorable performance attributes compatible with aviation use. ETBE is derived from the co-processing bio-ethanol and isobutylene – thus making it partially derived from renewable sources. It is a stable compound used in high performance fuels with a chemical formula is C6H14O. The presence of oxygen results in a more complete combustion in a piston engine and the "cleanest" exhaust emissions profile. ETBE’s Motor Octane Number is 103 MON and its Research Octane Number is 119 RON (AKI=111). ETBE has been tested in the US and used in a wide range of fuels throughout Europe and Asia for several decades.

See ETBE Technical Product Bulletin here

ETBE has a low water-solubility level which makes it suitable when blended for aviation gasoline use – e.g. in cold weather or high-altitude applications without freezing. This is in sharp contrast to alcohols (e.g. Ethanol) which are highly miscible with water and are generally unacceptable for use in aviation gasoline. Swift Fuels has conducted extensive research and testing to date and finds ETBE to be a viable octane booster which is compatible with all piston aircraft fuel systems. More testing and proprietary market research is currently underway.

ETBE is a low toxicity compound which is used as a high octane fuel blending component.

ETBE Component - Safety data sheets can be seen here and here.

Additional information on ETBE can be found at the following links:

EU/Global ETBE Fact Sheet

Mexico ETBE Fact Sheet

Lyondellbasell ETBE Fact Sheet

ETBE Product Stewardship - Global Safety Document

Does Swift Fuels offer assistance to airports with tankage issues?

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 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.

What is EAGLE and what is their role in relation to Swift Fuels deployment of unleaded avgas ?

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). Swift Fuels was an active participant in the original FAA/Industry-lead PAFI program from 2014 to 2018. And Swift Fuels has been and will remain engaged in an ongoing collaboration with EAGLE on a number of issues.

However, just like our UL94 unleaded avgas program, 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 in 2023. There is a possibility that Swift Fuels may elect to join the EAGLE certification 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. Depending upon the outcome of these discussions, Swift Fuels may choose to engage with the EAGLE certification process sometime within the next 2 – 3 years if we believe it benefits our stakeholders.

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
Based upon your research -- are “Aromatic Amines” safe to use as Octane Boosters in Avgas?

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 NOT 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, servos, elastomers, hoses, 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.
  • There is insufficient industry experience by ASTM International or any equivalent international quality control organization -- which leaves open the risk for litigation claims due to insufficient industry testing.
  • There is no thorough cross-industry evaluation of material compatibility issues by any such independent group substantiating the use of aromatic amines in avgas

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)

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.