- The FAA released Transition Plan V1.0 on July 30, 2026, committing to end leaded avgas use by the end of 2030, and by the end of 2032 in Alaska.
- About 222,000 registered piston-engine aircraft are affected, roughly 175,000 of them actively flying, burning an estimated 180 million gallons of 100LL in 2023.
- Only 212 US airports currently sell any unleaded avgas variant, against about 3,200 airports still selling leaded 100LL.
The Federal Aviation Administration has published Version 1.0 of its Transition Plan to Unleaded Aviation Gasoline, the document that sets out how the United States will stop burning leaded fuel in small aircraft by the end of 2030. The FAA announced the release on July 30, 2026, and the formal notice of availability appears in the Federal Register on August 3, 2026 at 91 FR 48969.
The plan commits the FAA to four phases. Fuel authorization and comparison testing is projected to finish in Spring 2027, market-experience building in mid-to-late 2028, and the national switch away from 100-octane low lead, known as 100LL, by the end of 2030 everywhere except Alaska, which Congress gave until the end of 2032.
This is not a proposal open for comment. The FAA ran a 60-day comment period on the draft between January 12 and March 13, 2026, and Version 1.0 is the revised document that came out of it. A summary of those comments is due in late 2026, along with an FAQ, and Transition Plan V2.0 follows at the close of Phase 1 in late 2027.
The scale is larger than most people outside general aviation realize. As of Summer 2026 the FAA counted roughly 222,000 spark-ignition piston-engine aircraft on the US registry, about 175,000 of them actively flying. They burned an estimated 180 million gallons of 100LL in 2023, per Energy Information Administration data cited in the plan.
What the FAA actually committed to
Section 827 of the FAA Reauthorization Act of 2024 directed the agency to move the piston fleet to unleaded fuel by 2030 “to the extent practicable.” The plan was signed out by Caitlin Locke, Associate Administrator for Aviation Safety Oversight and Certification. The work sits under the EAGLE initiative, short for Eliminate Aviation Gasoline Lead Emissions, a partnership formed in February 2022 by general aviation trade groups, the American Petroleum Institute and the FAA.
The FAA is testing three high-octane unleaded candidate fuels at its William J. Hughes Technical Center against three leaded reference fuels. It is also testing whether the unleaded fuels can be safely co-mingled with each other, a question that matters enormously for an airport with a single avgas tank.
Why people who live near small airports care
Tetraethyl lead has been added to aviation gasoline since 1921 to raise octane and prevent engine knock at high power settings. Piston aircraft are now one of the last legal uses of leaded fuel in the country, and the emissions land where the flying happens.
In 2023 the Environmental Protection Agency issued a final Endangerment Finding that lead emissions from certain aircraft engines cause or contribute to air pollution that may reasonably be anticipated to endanger public health and welfare under the Clean Air Act. The FAA is explicit that health questions are not its authority: EPA makes the finding, and the FAA’s job under 49 USC 44714 is to prescribe fuel standards in response.
The plan is unusually direct about where exposure concentrates. Flight schools run high volumes of touch-and-go operations in a tight box around the field, and those concentrated emissions may extend more than half a mile from the end of the runway. That is the geography of the neighborhoods and schools at the fence line of a busy general aviation airport. Community complaints about lead are named as one of the forces driving the transition, alongside a single remaining US supplier of tetraethyl lead that has signaled it will stop production.
For residents the plan’s practical guidance is thin: CDC lead poisoning prevention resources, and EPA’s advice that worried parents start with a doctor and a blood test through a Pediatric Environmental Health Specialty Unit. Disclosure stays a local fight. VisaVerge reported that Van Nuys Airport still lacks posted warnings about leaded aircraft fuel, and nothing here changes signage rules.
The unleaded fuels that already exist
Three high-octane unleaded fuels are in play as of Summer 2026. GAMI’s G100UL took the certification route and holds approved model list Supplemental Type Certificates covering essentially the entire fleet: STC SA01967WI for airframes and STC SE01966WI for every spark-ignition piston engine in the FAA type certificate database. GAMI has produced more than a million gallons commercially, but availability is tiny. The plan lists G100UL for sale at two airports in California, one in Mississippi and one in Texas.
Swift Fuels 100R also went the STC route. The FAA approved the initial 100R STC in September 2024, deployment began that November, and STC SA04651CH now covers more than 1,000 piston engines and matching airframes. UL100, from LyondellBasell and VP Racing Aviation, is instead going through the PAFI Fleet Authorization pathway, with full-scale testing due to finish in Fall 2026 and authorization in Spring 2027.
Separately, UL94, defined by ASTM D7547, and ethanol-free automotive gasoline are already approved for most low-compression engines. Their octane rating is not sufficient for the high-performance part of the fleet, which is why the 100-octane replacements matter.
The airport math is the hard part
About 3,200 US airports report selling 100LL, counting public-use and private facilities, and 2,741 of those are in the National Plan of Integrated Airport Systems. Against that, only 212 airports currently offer any unleaded avgas variant, and just 80 of those are NPIAS airports.
Most fields have room for one avgas tank, not two. There the switch “cannot be gradual,” which is why Phase 3 is sequenced: suppliers commit to fuels first, airports and fixed base operators announce their replacement fuel next, and only then do owners know which modification to buy.
Nothing lets an airport jump the gun. Congress required federally obligated airports to keep 100LL available, implemented as Grant Assurance 40, Access to Leaded Aviation Gasoline. FAA guidance updated December 10, 2025 makes clear that airports may not restrict 100LL until a replacement fuel meets the criteria in Section 770 of the 2024 Act. California passed its own ban on leaded fuel sales effective January 1, 2031, and Colorado is building early-transition incentives. Infrastructure pressure on GA fields is nothing new; the sector is already facing an advanced air mobility readiness gap.
Alaska gets two extra years
Section 771 of the 2024 Act gives Alaska until the end of 2032, and the plan targets December 2032 for the last 100LL sales in the state. Alaska has no dedicated refineries, deliveries are seasonal, operators typically receive 100LL once a year, and piston aircraft carry traffic that has no alternative. The Alaska clock starts once suppliers nationally commit to the fuels they will offer.
Supply sets the outer boundary everywhere else too. Roughly a 9 to 18 month stock of 100LL sits in the distribution system outside Alaska at any time, and meeting end-state demand means producing about 180 million gallons of unleaded avgas a year by the end of 2032.
What owners and operators should do now
Alterations are the piece owners underestimate. Changes could be as light as new placards and a flight manual supplement, or as heavy as ignition timing changes, new pistons, an anti-detonation injection system or an engine replacement. Which one applies depends on the fuel the local airport picks.
In-service reports are still being sorted out. The plan lists an October 2023 University of North Dakota concern about UL94 and valve seat recession in Lycoming engines, a December 2024 report of G100UL affecting aircraft paint and swelling nitrile O-rings, and Cirrus service advisory SA24-14 from June 2024 on fuel tank sealant degradation. The FAA issued a Special Airworthiness Information Bulletin in March 2025 asking for more reporting, and that reporting feeds the Phase 3 decisions.
- Owners: check whether an existing STC covers your airframe and engine, and file experience reports under the March 2025 SAIB.
- Flight schools: EAGLE’s July 2023 guidance on transitioning a flight school to unleaded avgas is the starting point, and low-compression trainers are the easiest early switch.
- Airports and FBOs: NPIAS fields can seek Airport Improvement Program funding for a fuel farm serving an additional fuel type.
- Neighbors: track your airport’s replacement-fuel announcement, the point at which the local decision becomes public.
The next hard checkpoint is Spring 2027, when Phase 1 closes and the FAA publishes Transition Plan V2.0. Until then the safety questions that dominate general aviation are unchanged, from the human factors behind general aviation crashes to the regulatory push in EASA’s general aviation safety initiatives. The full plan sits on the FAA’s unleaded aviation gasoline page.
Frequently Asked Questions
When will leaded aviation gasoline be banned in the United States?
Congress directed the FAA to end the use of leaded aviation gasoline for piston-engine aircraft by the end of 2030 everywhere except Alaska, which has until the end of 2032. The FAA Transition Plan V1.0, released July 30, 2026, sets out the four phases for reaching those dates.
How many aircraft are affected by the 100LL phase out?
As of Summer 2026 the FAA counted roughly 222,000 spark-ignition piston-engine aircraft on the US registry, about 175,000 of which were estimated to be actively flying. Those aircraft consumed an estimated 180 million gallons of 100LL in 2023 based on Energy Information Administration data.
Which unleaded aviation fuels are already approved?
GAMI’s G100UL holds approved model list STCs SA01967WI for airframes and SE01966WI for spark-ignition piston engines. Swift Fuels 100R holds STC SA04651CH covering more than 1,000 engines. UL94, defined by ASTM D7547, is approved for most low-compression engines but lacks the octane for high-performance aircraft.
Can I still buy 100LL at my airport after 2026?
Yes. Congress required federally obligated airports to keep 100LL available under Grant Assurance 40, Access to Leaded Aviation Gasoline. FAA guidance updated December 10, 2025 prohibits airports from restricting 100LL until a replacement fuel meets the criteria in Section 770 of the 2024 Reauthorization Act.
Is the FAA taking public comments on the unleaded avgas transition plan?
No. The FAA ran a 60-day comment period on the draft plan from January 12 to March 13, 2026, and Version 1.0 reflects those comments. The August 3, 2026 Federal Register item is a notice of availability with no comment deadline. A public comment summary is due in late 2026.
What modifications will my aircraft need to run unleaded fuel?
It depends on the fuel your airport stocks. The FAA says changes range from new placards and a flight manual supplement to ignition timing changes, new pistons, an anti-detonation injection system, revised operating limitations or an engine replacement. Owners are advised to wait for their airport’s fuel announcement first.
How does aviation lead affect people living near general aviation airports?
The EPA issued a final Endangerment Finding in 2023 that lead emissions from certain aircraft engines endanger public health and welfare under the Clean Air Act. The FAA plan notes that concentrated emissions from flight training operations may extend more than half a mile from the end of a runway.
Why does Alaska get two extra years to switch to unleaded fuel?
Section 771 of the 2024 FAA Reauthorization Act gives Alaska until the end of 2032. The state has no dedicated refineries, operators typically receive 100LL only once a year, fuel delivery is seasonal, and piston aircraft provide transportation with no alternative in many communities.
