A California state court is preparing to hear a motion March 5, 2025, brought forth by the California Center for Environmental Health (CEH), to force several California FBOs and general aviation fuel distributors to solely offer a new unleaded avgas.
The court action is “premature and counterproductive,” and could “cause undue harm to the general aviation community,” according to officials with the General Aviation Manufacturers Association (GAMA).
“There is a concerted effort currently underway to ensure that there is a safe and efficient transition to an unleaded future for piston-engine aircraft,” said Pete Bunce, GAMA president and CEO, referring to the efforts of the Eliminate Aviation Gasoline Lead Emissions (EAGLE) initiative, which debuted in 2022 with the mission to make GA lead-free by 2030.
“We have seen some key milestones reached to progress efforts, but there is still significant work needed before a full-scale transition can take place,” he continued. “The CEH motion is based on a brand new high-octane unleaded fuel, which is currently available at just two California airports. Although the FAA issued an STC allowing for its use in airplanes, this is the only aviation fuel that has not been subject to a stakeholder consensus peer review process and does not have the endorsement for use by piston-engine and aircraft Original Equipment Manufacturers (OEMs) or other stakeholders, such as distributors and FBOs, due to lack of transparency and understanding of the new fuel’s composition and performance properties. Additionally, this fuel cannot be used in piston helicopters.”
The fuel he’s referring to is General Aviation Modifications Inc.’s G100UL, which received approval from the FAA in September 2022.
This approval and the sale of the unleaded fuel at some California FBOs triggered the CEH to file the latest court motion based off an agreement the environmental center reached with FBOs years ago where the FBOs agreed to sell only unleaded fuel once an unleaded fuel was available.
But aviation advocates counter that while G100UL is now available for sale, many questions still remain.
“There are also questions and a need for additional information about materials compatibility and safety in both aircraft and fuel distribution infrastructure,” Bunce went on in his prepared statement, released March 3, 2025. “The general aviation industry is committed to supporting a viable unleaded avgas solution, but a forced and premature transition will not be in the interest of the aviation community or public in the long run.”
He adds that there have been notices to the public from Cirrus Aircraft, Lycoming, Piper Aircraft, and Textron Aviation that “there are questions and potential concerns about the specified unleaded avgas product CEH is attempting to prematurely force on the piston aircraft community.”
“In addition to these warnings, aircraft manufacturers Aviat Aircraft, Diamond Aircraft Industries GmbH, Enstrom Helicopter Corp., Piper Aircraft Inc., Schweizer RSG, and Robinson Helicopters each submitted information to the court that stated the new unleaded avgas variant was not approved or supported by manufacturers for use in their models, given their companies lacked the information necessary to verify its safety and material compatibility,” Bunce said. “Additionally, several aviation trade organizations, including GAMA, submitted declarations to ensure the court was aware of the general aviation piston industry’s relevant perspectives.”
According to court documents, several individual aircraft owners in California also have filed declarations related to adverse issues potentially encountered by using G100UL, Bunce noted.
“Additionally, according to court documents, a California-based FAA Flight Standards District Office has initiated an investigation into some of these possible material incompatibility issues identified in several piston airplanes,” he said. “In the interest of aviation safety, GAMA calls for transparency and openness in a manner consistent with established industry practices for all transportation fuels — a broad stakeholder peer review assessment of new fuel property and performance data through the ASTM consensus standards process or similar — to include collaboration among fuel producers, chemical manufacturers, testing laboratories, fuel distributors and piston-engine aircraft and component manufacturers, etc.”
While G100UL underwent more than a decade of testing by the FAA, it has not been submitted to ASTM and GAMI officials say they have no intention of submitting the fuel to the organization, which develops international standards for products, materials, and services.
GAMA officials also have called on the FAA to issue a Special Airworthiness Information Bulletin or other notice to “properly inform the general aviation community of potential issues and possible airworthiness impacts while the alleged FAA investigations continue and/or mitigation efforts, as determined necessary by the FAA, are developed.”
Want to know more? The public statements and court submitted documents can be found here.
