Guide for Airports on Unleaded Avgas Transition Released Ahead of FAA Final Plan

In June 2026, the National Academies Press released a detailed guide and primer aimed at helping airports navigate the transition from leaded to unleaded aviation gasoline. This publication comes while the Federal Aviation Administration (FAA) has yet to finalize its own Transition Plan, following the close of its public comment period earlier in the year. The FAA has stated that the Transition Plan will be released first, with a summary of public comments expected later in 2026, leaving airports to prepare amid lingering uncertainties about the final regulatory framework.

The guide was produced under the Airport Cooperative Research Program (ACRP) Project 03-73 and is intended to complement, not replace, the forthcoming federal plan. Sponsored by the FAA and administered by the Transportation Research Board, it focuses on bringing the national policy goals to a practical level suitable for airport operators. The guide tackles the complexities airports face when implementing changes to fuel infrastructure, demand estimation, and safety protocols during the transition to unleaded avgas.

The context for the transition traces back to the Environmental Protection Agency’s (EPA) 2023 finding that lead emissions from piston-engine aircraft burning leaded avgas represent a significant public health hazard. The guide notes that, following the elimination of leaded automotive gasoline, leaded aviation fuel remains the largest source of airborne lead emissions in the United States. The EPA highlighted the risks to cognitive function, academic performance, and overall health posed by lead exposure, emphasizing there is no safe exposure threshold.

Federal law also frames the transition timeline and requirements. The FAA Reauthorization Act of 2024 mandates that airports offering leaded avgas in 2022 must continue to do so through December 31, 2030, unless a suitable unleaded replacement is authorized by the FAA and broadly accessible. This legislation creates a phased approach, compelling airports to balance the ongoing provision of traditional 100LL fuel with preparations for new unleaded options, a process complicated by varying infrastructure and fleet characteristics at individual airports.

The ACRP guide lays out a methodical approach for airports beginning with assessing their current fuel supply chains and on-site operations. It then proceeds through analyzing local fleet composition for fuel compatibility, estimating demand for unleaded alternatives, reviewing infrastructure capabilities, identifying funding mechanisms, and selecting the appropriate unleaded fuels. The sequence culminates in implementation steps including staff training, safety procedures, and ongoing monitoring of the transition’s progress.

Regarding available unleaded fuels as of early 2025, when the guide was finalized, mogas, Swift Fuels UL94, GAMI G100UL, and Swift Fuels 100R were commercially available or nearing commercial availability; meanwhile, UL100E and VP Racing Fuels products were still undergoing FAA testing. The guide stresses that while some fuels have established ASTM standards, others do not, influencing considerations such as misfueling risk and insurer acceptance. Importantly, not all aircraft are certified to use these fuels without supplemental type certificates (STCs), imposing further variables airports must address locally.

The guide includes practical tools for airports: a transition checklist, survey templates for both individual aircraft owners and multi-aircraft operators, an inventory spreadsheet, and a fuel cost evaluation tool. These resources aim to help airports structure their transition efforts by quantifying based aircraft compatibility, assessing infrastructure needs, and projecting financial impacts. Case studies from seven airports engaged in the unleaded avgas rollout, including those in challenging environments like Alaska, provide real-world insights into the operational hurdles faced.

Despite the guide’s focus on airports, many open questions remain regarding the experience of aircraft owners and pilots. Issues such as long-term availability of unleaded fuels, comparative pricing, warranty and insurance implications, resale value of modified aircraft, and the economic feasibility of obtaining STCs are not fully resolved. The final FAA Transition Plan, currently pending release, is expected to address some of these nationwide concerns but has yet to provide definitive answers.

The publication of this ACRP guide represents a tangible step for airports actively planning the shift away from leaded avgas. By providing structured processes and tools tailored to airport-level challenges, it helps operators prepare proactively amid regulatory and market uncertainties. With the federal deadline for ending leaded avgas sales set for the end of 2030, airports and operators alike must now integrate these practical resources into their transition strategies while awaiting the FAA’s final regulatory framework.