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Fuel for all

Unleaded avgas progress report

By Paul Millner

The ability to create an unleaded avgas that meets the needs of the entire general aviation fleet has been vexing the industry for decades. There has been recent progress, but challenges remain.

Illustration by Infomen
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Illustration by Infomen

In an effort to continue progress, the FAA hosted an industry roundtable discussion on unleaded avgas on November 15 in Washington, D.C. AOPA attended, as did a cross section of oil companies, independent unleaded avgas developers, Textron Aviation, a smattering of independent experts, and other trade associations representing airport operators, FBOs, and manufacturers.

The roundtable attendees are working to tackle one of the toughest issues facing general aviation: the removal of lead from avgas. Recent developments seem promising, but in many ways they—combined with heightened environmental concerns—have also led to confusion and angst for aircraft owners.

From the beginning of the effort to develop an unleaded avgas, AOPA has held the position that the only acceptable solution is one that meets the needs of the entire fleet of 200,000 aircraft.

With FAA approval of General Aviation Modifications Inc.’s (GAMI’s) 100-octane unleaded avgas for a small number of engines and airframes this past July, pressure on both the EPA and the FAA to address lead phaseout has increased. At the meeting, the FAA estimated the EPA/FAA process to ban leaded gasoline would take four to six years. However, at the National Association of Clean Air Agencies meeting in October, the EPA said it’s refocusing on an endangerment finding, a significant milepost in the process to ban lead. European regulators are also moving toward banning tetraethyl lead imports, now that the sole manufacturer, in England, is outside of the European Union. TEL is the octane-boosting component that contains lead. However, several airport operators are not waiting. Regulators and airport operators in a handful of mostly Western states have begun moving toward banning the sale of leaded avgas, even though a 100-octane unleaded fuel is not yet available.

While some pilots like to argue that the amount of lead emitted by general aviation is tiny, any amount of lead is a problem.

The EPA has been very effective over the past 40 years in moving industry to reduce lead from automotive fuel. Avgas emissions have gone down as well (with the transition from 100/130 to 100LL). However, avgas-related lead emissions remain an issue.

Moreover, there’s a security of supply issue. The last leaded mogas (motor gasoline, designed for automobiles) blender in the world earlier this year converted to unleaded fuel. That leaves aviation’s small demand (avgas is about one-tenth of one percent of U.S. mogas production, and even less in the rest of the world) to support the sole remaining Octel TEL plant in Liverpool, England. The lead plant’s owner emerged from bankruptcy a few years back. But environmental pressures on that plant continue, bringing into question the long-term feasibility of its business plan. At the moment, though, Octel claims it will provide TEL for avgas blenders as long as there is demand.

These continuing threats require action on the part of the FAA, the aviation industry, and aircraft owners. The recent FAA roundtable meeting was another step in that process.

At the meeting, it became clear that the term “fleetwide solution,” which is now commonly used, is causing confusion. Many understand that GAMI and Swift Fuels are on track to provide a fleetwide solution, as both claim that their 100UL fuels will, at some point, be FAA-approved for every aircraft and engine in the piston-engine fleet. However, both are pursuing their approvals by getting supplemental type certificates (STCs) for each combination of airframe and engine, which is not how the transition to an unleaded fuel was originally expected. The FAA had instead planned for candidate fuels to go through a series of tests overseen by the agency and with oversight from others in the industry through the Piston Aviation Fuels Initiative (PAFI) process. Both GAMI and Swift elected to have their fuels approved outside the PAFI process.

At the roundtable, FAA Executive Director for Aircraft Certification Service Earl Lawrence explained that “technically” it would be possible for the FAA to approve the STC candidates from GAMI or Swift as that fleetwide solution. But, administratively, the FAA has never made an approval like that, and it could take years to work out the regulatory process by which such a determination might be made. So even if someone makes a fuel that is FAA approved for every aircraft and engine in the fleet, you can’t call it a “fleetwide solution” because that term only applies to fuels approved via a specific process. The confusion is likely to continue, as both GAMI and Swift refer to their fuels as fleetwide solutions, without the FAA quotation marks.

There was some discussion of Lycoming’s recent approvals for use of “100 unleaded” fuels that comply with ASTM specification D910. However, no such fuels exist, nor are any of the proposed fuels going to be D910 compliant; they all require a new specification. Lycoming also approved 100VLL—100 very low lead. However, that is mostly a meaningless declaration because the refineries that can make 100VLL are already doing so and selling it as 100LL, to minimize lead additive expense. The only 100LL that isn’t currently 100VLL compliant is made by those that can’t meet the specification, given their refinery’s constraints. So 100VLL offers no significant reduction in actual lead emissions.

There are disagreements among the participants on what the future fuel specification needs to look like, or who needs to approve it; what additives are appropriate, or what effects they might have on the engine or fuel system; or the relative transparency of FAA PAFI proceedings versus the FAA STC approval process. These are things that will get worked out, and the FAA’s commitment to roundtable meetings to surface and work the issues is a good step.

The FAA had proposed that it could investigate engine modifications, engine replacements, and even electric aircraft as potential backup plans to unleaded avgas. The roundtable participants urged the FAA to focus on the unleaded avgas approval and rollout, and not on any number of illusory alternatives. Interestingly, some participants criticized the STC process as non-transparent, although GAMI’s and Swift’s patents are online for all to understand how they’re addressing the issues.

There’s more promising activity in the unleaded avgas sphere now than ever since the launch of the Coordinating Research Council Unleaded Avgas Development Group industry effort in 1991. Several contenders look viable, and great effort is going into getting those fuels to market. There are some possible supply disruptions on the horizon, but AOPA is working with the FAA to oppose an ill-timed lead phaseout prior to the ready availability of the oncoming unleaded avgas fuels. While the process of creating, approving, and delivering a high-octane unleaded has proven much more complicated than was anticipated at the initiation of the joint industry effort, we are getting very close. However, to be clear, even when approved fuels are available, the mass manufacturing and distributing will likely take years to implement, so don’t expect a 100-octane unleaded fuel to be at your airport anytime soon.

The threat of 100LL being phased out before an acceptable unleaded fuel for all airplanes and a reliable distribution plan is in place is a major concern, said AOPA President and CEO Mark Baker. “We need a smart transition here. We have only one chance to get this right and we need all stakeholders to come together to move this issue forward safely and efficiently,” he reiterated. “AOPA is committed to working with all those affected to make this transition successful.”

Stay tuned as we’ll continue to cover developments regularly.

Paul Millner is an aviation fuels expert and AOPA consultant.

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