FAA requests proposals for options to transition GA to unleaded fuel

WASHINGTON, D.C. – The FAA has asked the world’s fuel producers to submit proposals for options that would help the general aviation industry make a transition to an unleaded fuel.

The FAA is committed to the development of a new unleaded fuel by 2018 that would minimize the impact of replacing 100 octane low-lead fuel for most of the general aviation fleet, officials said in a prepared release.

The FAA will assess the viability of candidate fuels in terms of their impact on the existing fleet, their production and distribution infrastructure, their impact on the environment and toxicology, and economic considerations.

“General aviation is vital to the U.S. economy and is an important form of transportation for many Americans,” said Transportation Secretary Ray LaHood. “We need to work with industry to develop an unleaded fuel that advances aviation safety and improves the environment.”

The FAA is asking fuel producers to submit  data packages for candidate replacement unleaded fuel formulations for evaluation by the FAA by July 1, 2014.

By Sept. 1, 2014, the FAA will select up to 10 suppliers to participate in phase one laboratory testing at the FAA’s William J. Hughes Technical Center. The FAA will select as many as two fuels from phase one for phase two engine and aircraft testing. That testing will generate standardized qualification and certification data for candidate fuels, along with property and performance data.

Over the next five years, the FAA will ask fuel producers to submit 100 gallons of fuel for phase one testing and 10,000 gallons of fuel for phase two testing.

“The FAA knows the general aviation community and the Environmental Protection Agency are focused on this issue, and we look forward to collaborating with fuel producers to make an unleaded avgas available for the general aviation fleet,” said FAA Administrator Michael Huerta.

The President’s 2014 budget includes $5.6 million in research and development funding for the William J. Hughes Technical Center to conduct the fuels evaluation testing. Candidate fuel testing will be funded by the government and in-kind industry contributions, in a multi-year program.

To date FAA has tested over 279 fuel formulations in an attempt to find a “drop-in” solution, which would require no aircraft or engine modifications. The latest request responds to the July 2012 Unleaded Avgas Transition Aviation Rulemaking Committee report to the FAA, which noted that a “drop-in” unleaded replacement fuel is unavailable and may not be technically feasible.

That is why an industry-government initiative called the Piston Aviation Fuels Initiative (PAFI) will facilitate the development and deployment of a new unleaded avgas with the least impact on the existing piston-engine aircraft fleet. PAFI is key to the selection and implementation of an unleaded fuel across the existing general aviation fleet, FAA officials noted. The FAA and industry-group leaders also recently formed the PAFI Steering Group (PSG), to facilitate, coordinate, expedite, promote and oversee the PAFI.

There are approximately 167,000 aircraft in the United States and a total of 230,000 worldwide that rely on 100LL. It is the only remaining transportation fuel in the United States that contains the addition of tetraethyl lead (TEL), to create the very high octane levels needed for high-performance aircraft engines. Operations with inadequate octane can result in engine failures.

The request is available here. For more information on the FAA’s efforts on avgas, click here.


  1. Greg M says

    What if ethanol was no longer the thorn in mogas? This is possibly closer that many may think. But first an unleaded avgas replacement must be and will be certified and available. As of this week SwiftFuel’s 100SF pilot production plant is nearing completion. This is due to major investors recognizing the value of this replacement unleaded avgas above all other contenders. With production from the pilot plant, proof of concept will have been established and other plants (including retired ethanol plants of which there are many through out the country) will start to come online after the completed certification process. BTW, SwiftFuel could also meet the U.S. government biofuel requirements now in place for ethanol in mogas. This will also enable SwiftFuel to be produced in much larger quantities than only required for avgas. This should also help keep cost down for SwiftFuel’s 100SF avgas. Waiting until 2018 for a solution is much too long. SwiftFuel could be in your aircraft much sooner than 2018. How about next year?

    • David Gaeddert says

      Someone else as eccentric/sensible as I! How ’bout 100SF in my HD Sportster 1200, as well as the Piper Cherokee I fly? How about next year?

  2. Tim says

    It would be cheaper for everybody to just replace 100LL with 94UL and pay the airplane owners who can only use 100LL. Maybe even buying new engines to replace all 100LL-only engines would cost less than doing dead-end research for 20 years and then continuing with 100LL for next 10 years.

  3. Bruce Corey says

    I don’t get the requirement of the FAA for only one “drop in fuel”. When I started in aviation there were 2 grades of avgas, 80/87 and 100/130, practically every airport sold both grades, most even had fuel trucks that held both grades. Why, especially today with the availability of self contained fueling stations, can there not be 2 kinds of fuel again? You could have unleaded and leaded avgas for a time while a substitute fuel for aircraft that actually need high octane is developed or alcohol free premium mogas and whatever new fuel evolves. The mogas option would probably get more people flying again as the price “should” be lower. I worry about the storage life of mogas in airplanes
    considering how fast it goes bad in the lawnmower but I suppose that can be worked around by adding fresh fuel for each flight.

  4. Jscott says

    And once again, the cost to the end user isn’t even a consideration for the 100LL replacement. They just expect us to pay the bill regardless of the solution, which is once again why General Aviation is dying.

  5. Paul says

    For goodness sake! Premium mogas needs to be made available. Our FBOs could help with this problem instead of waiting another 20+ years for the FAA to do something. I don’t know if this is our problem, but the city supplies our fuel at our airport. I don’t can’t even get a response about mogas. Ethanol is a political issue. It has no value, NONE, in fuel. As usual, have no fear, the government is here to help…

  6. Kent Misegades says

    Clearly the FAA does not read GA News. If they did, they would not have stated the bogus number of 167,000 aircraft that need 100LL. As GA News reported on Juky 12th of last year, over 80% of the entire piston engine fleet can run safely and legally on premium mogas today. The remaining 20% could operate on mogas pending small mods or the new water injection system from INPULSE of Wellington, KS. It is very clear that the FAA continues to accept only a single, one size fits all, drop in replacement for 100LL, despite a 20+ year failed effort by leading oil companies to find one. What is the definition of insanity?

  7. Lee Ensminger says

    So, the FAA has already been working on this for…how many years? Recently, I’ve read where they have now promised to wrap this up in “only” another eight years. Today, they’re requesting proposals from fuel producers for an unleaded alternative. What am I missing? Have they done NOTHING up to this point? Are they just getting serious about it now? Who didn’t see the need to eliminate lead? It’s a transportation nightmare and a hazard. Personally, I’d like to see aviation fuel produced as it is now, and simply leave out the TEL. I realize that throws the really high-performance plane owners under the bus, and that’s not right, even though they are a small percentage of piston aircraft. What about an additive they could put in the fuel they use? I suppose it would cost way too much to certify, but isn’t it true that most of our airplanes would be perfectly happy on the base aviation stock without the TEL? I’m told that would be about 92 octane. Alternatively, using 91 octane mogas could be a solution if we weren’t pumping that stupid ethanol into it. My personal opinion is that ethanol in fuel has been a disaster.

    • Greg W says

      Lee, the 100LL with out tet. lead that you speak of is the FAA approved fuel 94UL (astm D7592-2010). It would be a drop in, no STC, fuel for aircraft certified on equal or lesser octane, just as we use the 100LL in place of 91/96 or 80/86. The astm D910 spec. did not until the last revision include a minimum amount of lead only a maximum. What that means is the the leaded grade 80 was often no-lead fuel it was added if needed on a batch by batch basis. This was a big controversy when revealed by announcing 100VLL,was most of the 100LL already in use. If D910 was changed back to not having the minimum lead content it would greatly simplify the process for the majority of users. Those that need the 100 will need to make changes, if those changes are done at overhaul the added cost would be much less as well.

      • Lee Ensminger says

        Greg, thanks for your response. Obviously, you are not with the FAA or any other governmental agency, as your answer is far too practical and easily accomplished. Everything you said made sense, which means there is a 0% chance of implementing the removal of the minimum lead standard, allowing us to have quality fuel which would be easily transportable. And, as Bruce says, above-ground, freestanding automated self-serve fuel systems are easily installed, unlike the underground tanks of the past. The solution seems so obvious…to everyone except those with the authority to implement the change.

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