Swift Fuels 100R Unleaded Avgas: Available on “Restricted Use” Basis
Posted on November 11th, 2024
West Lafayette, IN: In recent weeks, several airports in California have brought to Swift Fuels’ attention that they were approached by a fuel producer to use G100ULTM unleaded avgas which does not have an ASTM International fuel specification. The airfields noted that the producer of G100ULTM was exerting extreme pressure on the California airports leadership – hoping to motivate them to begin buying their fuel. Many California airports said their leadership will wait to use 100-octane unleaded avgas alternatives that are commercially available with an ASTM Specification as it assures a more thorough testing criteria has been achieved for many items beyond the purview of FAA. Recently one airport was compelled to offer G100ULTM unleaded avgas at highly discounted pricing for the fuel and STC’s to make it appear attractive to buyers despite market concerns recently reported about paint staining/stripping, bladder leaks, elastomer warnings, Cirrus advisory SA24-14, and Lycoming warnings. These publicized concerns stem from the fact that G100ULTM contains a large quantity of xylene plus an aggressive solvent (3- 4% m-toluidine) known to potentially alter the performance of certain fuel system parts – particularly elastomeric-type parts. For unknown reasons, the producers of G100ULTM have been unwilling to submit their fuel to ASTM International for industry-wide vetting.
Upon the FAA’s announcement in September that Swift Fuels’ initial 100R STC was approved for certain aircraft, several isolated airfield/flight schools approached Swift Fuels and asked us for the right to fly their Cessna 172R/S aircraft models using 100R if they prohibited any resale opportunities. Swift Fuels consulted with several experts on this matter. Last week, Swift Fuels deployed 100R on a “restricted use” basis using our FAA-approved company specification which matches exactly our proposed ASTM International production specification. We specified that only Cessna 172R and Cessna172S aircraft can utilize the 100R fuel at these specified locations where 100LL is also sold. These two aircraft models operate on the same engine model – a Lycoming IO-360-L2A. By operating on a restricted use basis without an ASTM Specification, the 100R fuel is not yet commercially available for broad distribution or use. Only specific registered aircraft can use the fuel at specific airfield locations.
“RESTRICTED USE” vs. COMMERCIALLY AVAILABLE
The recent deployment of 100R unleaded avgas on a “restricted use” basis at selected airfields also selling 100LL has raised a question. The question stems from the fact that our ASTM International production specification for 100R has not been fully completed yet. And we have stated consistently that our fuel will only become “commercially available” once the FAA certifications plus the ASTM International fuel specification have been earned. The term “commercially available” now used in the marketplace is a concept that has been debated by various legal advisors in recent months. Swift Fuels has been clear and consistent in our belief that a “commercially available” fuel must combine FAA-certification approvals (engines / airframes) using a fuel along with an ASTM International specification so that that the marketplace can access it openly across the global aviation fuel supply chain. The principle of this argument is backed-up by language in the FAA Reauthorization Act of 2024 for airfields with grant assurances – limiting the removal of 100LL until an unleaded avgas alternative is shown to comply with FAA certifications and industry consensus fuel standards. The ASTM International specification provides the industry consensus quality assurances required by the fuel supply chain (i.e., regulators, fuel distributors, handlers, insurers, NTSB, et al.). Thus, we believe our 100R FAA-approved fuel will only become commercially available once the ASTM International specification is approved.
IS 100R SAFE FOR USE NOW?
- ENGINE TEST - Swift Fuels has completed over 350-hours of very high stress engine endurance testing on the Lycoming IO-360-L2A – well beyond the minimum required 150-hour FAA certification test. PAFI and Lycoming endorsed our longer duration operability test and Hartzell endorsed using a propeller to instill realistic vibration stresses. Physical wear of key engine parts was measured before and after the test and found to be well within the recommended wear limits, most were within “NEW” wear limits, spark plugs ran clean, intake and exhaust valves were clean, and there was no valve seat recession. There was no loss of compression in the cylinders at 78/80 psi after 400 stressful test hours. Detonation testing was completed in an FAA-conforming Lycoming’s test facility in Williamsport, PA and reported adequate detonation margin. The overall results were excellent and were fully endorsed by our FAA certification team. This information has also been presented to ASTM International.
- FLIGHT TEST - Swift Fuels completed flight testing with 2 experienced FAA test pilots. The pilots flew a Cessna 172R/S and performed comparative tests vs. 100LL. They did fuel starvation, in-flight restarts, hot weather, cooling climb tests, balked landing climb, and more. Once again, the FAA reported that 100R performed in flight testing the 172R/S model was as good or better than 100LL in all test results. The overall results were then endorsed by our FAA certification team. This information has also been presented to ASTM International.
- COMPATIBILITY / FIT-FOR PURPOSE - Swift Fuels conducted a wide range of fuel tests called out in ASTM D7826 including fuel properties, fit-for-purpose, toxicology, water solubility, intermixability, and material compatibility. Swift Fuels tested paint, bladders, epoxy, O-rings, sealants, hoses, diaphragms, filters, metals, and many more items according to strict ASTM International standards. Many dozens of tests were completed over a multi-year program. The overall results were excellent and were endorsed by our FAA certification team in formulating the issuance of the initial 100R STC for the engine and airframes. This information has also been presented to ASTM International.
- BREADTH OF TESTING - No other unleaded fuel has successfully completed such a comprehensive battery of FAA and ASTM International testing required on a specified engine / airframe combination. These results were validated by FAA in their Swift Fuels STC decision in September 2024. The restricted use of 100R in this temporary program is limited to the engines and aircraft as outlined in the FAA STC.
WHY NOT WAIT FOR 100R’s ASTM INTERNATIONAL SPECIFICATION?
Swift Fuels’ CEO has been quoted often that waiting for the completion of the ASTM Production Specification is the best answer for the industry. “Be patient: 100R unleaded avgas is coming soon.” In the past several months, Swift Fuels has published ~ 500 pages of research documents to ASTM International and is currently balloting a production specification for 100R. No other 100-octane unleaded fuel being evaluated at this time has as much comprehensive FAA and ASTM research data in the hands of industry compared to Swift Fuels 100R. This comprehensive research follows the ASTM guidelines for new aviation fuels outlined in ASTM D7862. Swift Fuels consulted experts and then made the determination that our 100R fuel can perform safely on a restricted use basis on Cessna 172R/S models as we wait for the final completion of the ASTM International ballot for our production specification. We expect the 100R production specification will be completed within the next several months. We are working closely with our industry collaborators to adjudicate the fuel specification coupled with our published industry research. These matters are highly technical and take time. We have over 80 industrial members around the world collaborating with us on the review of our 100R ASTM fuel specification. This ASTM standard of care is what quality fuels require in the global marketplace. The fuel producers of G100ULTM have completely avoided executing the ASTM/industry testing and fuel specification process - thereby disregarding a mission critical step in the industry's transition to unleaded fuel. In the meantime, the market in California has been challenging due to strong levels of community activism and local regulatory actions that sometimes do not follow the norms or timing of gaining of industry consensus. We thank the airports that have followed our advice to wait for the approvals to become commercially available tied to the timing of our 100R ASTM International specification. As many pilots know, we continue to grow our UL94 avgas market – now with over 9 years servicing commercial customers across the US. So, last week we made an exception allowing for the restricted use of 100R unleaded avgas to offset a localized challenge, to again highlight the importance for ASTM International, and to help maintain the motivation across the industry that our 100-octane commercially available unleaded fuel is coming soon. Our firm believes that the quality of our detailed fuels research will clearly reveal itself in the months ahead as our 100R fuel becomes known. We will strive to transparently differentiate our 100-octane fuel from all other potential unleaded products in the market as the transition to replace 100LL continues.