EAGLE Initiative Outlines Strategy for Lead-Free Future

By the end of 2030, there is a national goal for the general aviation community to move to unleaded aviation fuels. EAGLE, short for Eliminate Aviation Gasoline Lead Emissions, is a joint industry/government initiative bringing together general aviation - aircraft and engine manufacturers, fuel developers and producers, maintenance professionals, fix-based operators (FBOs), airports, federal regulators, and, most importantly, aircraft owners and pilots - to ensure a safe, smart, and smooth transition to unleaded fuels for piston aircraft.

The need for an unleaded fuel

The EPA issued a formal endangerment in 2023 finding identifying lead emissions as a public health risk, which by law requires a cut to these emissions. At the same time, indications are that the production of tetraethyl lead (TEL) - the chemical additive that gives 100LL its low-lead - is eventually coming to an end. Even without new regulations, the long-term availability of 100LL is uncertain.

Add to that mounting pressure from state and local governments to restrict or outright ban the use of leaded avgas, and it’s clear that inaction is not an option, according to EAGLE, which states that a suitable replacement fuel must be developed and deployed.

A unified, industry-backed approach

EAGLE’s mission is to guide the transition to unleaded avgas in a way that ensures reliability, protects safety, and maintains the economic viability of general aviation. The initiative provides advice and guidance to government, industry and fuel developers.

EAGLE builds on the technical testing already underway through the FAA’s Piston Aviation Fuels Initiative (PAFI) being applied to LyondellBasell/VP Racing’s candidate fuel, while also supporting Supplemental Type Certificate (STC) pathways used by General Aviation Modifications, Inc. (GAMI) and Swift Fuels. In simple terms, EAGLE supports multiple pathways to achieve a lead-free solution that works across the diverse piston-engine fleet.

Accomplishments thus far

Several unleaded fuel candidates are already in the pipeline:

· G100UL by GAMI has been granted an AML-STC for most piston-engine airplanes and is working to expand this to piston-engine rotorcraft.

· 100R by Swift Fuels is STC-approved for some Cessna 172 models and their respective engines, with more approvals expected.

· UL100E, developed by LyondellBasell and VP Racing, is undergoing fleet authorization testing via the FAA’s PAFI program.

But FAA approval alone is not the finish line. Each stakeholder involved in deploying and supporting a new fuel must have the data needed to make informed decisions to produce, store, distribute, and support safe aircraft operations.

This includes technical understanding of fuel composition and properties like materials compatibility, detonation resistance, and engine durability. EAGLE is closely monitoring the FAA-led comparative testing program to ensure the market has consistent, apples-to-apples data on the fuel candidates.

Preparing the market and your aircraft

Transitioning the GA fleet and fueling infrastructure to unleaded avgas is no small feat. It’s more than testing fuels—it’s about preparing general aviation. That means working with fuel producers, distributors, and FBOs, and making sure aircraft owners and mechanics have the resources they need to make an educated transition.

Unleaded fuel isn’t just a regulatory requirement, it offers real benefits for aircraft owners. AOPA testing has shown less engine wear with unleaded fuel, and Rotax engines recommend longer oil change intervals - 100 hours on unleaded versus 25 with 100LL - pointing to improved engine health and reduced maintenance.

Congress and the FAA have made clear that 100LL must remain available until a fuel has been authorized for use by the Administrator as a replacement in nearly all piston-engine aircraft and engine models; and meets either an industry consensus standard or other standard that facilitates the safe use, production, and distribution of such unleaded aviation gasoline, as determined appropriate by the Administrator.

FAA’s new Grant Assurance 40 requires federally funded airports to continue offering 100LL if they did so prior to 2022, unless an alternative has been formally approved and adopted.

As of April 2025, the FAA has confirmed that no such fuel meets these criteria yet.