Showing off G100UL

The movers and the shakers of GA are descending on Ada, Okla., these days, as concern about a replacement for 100LL heats up.

One of those potential replacements, G100UL, is being developed by Ada-based General Aviation Modifications, Inc. (GAMI), which recently hosted AOPA President Craig Fuller, as well as Cessna President Jack Pelton. Other heavy-hitters in the GA industry have also been invited to take an up-close look at the new fuel, while GAMI officials expect a “deluge” of inquiries about G100UL during AirVenture in Oshkosh, which starts next week.

Fueling that concern is an Advanced Notice of Proposed Rule Making issued by the Environmental Protection Agency in April, with many in the industry predicting that 100LL will be outlawed in the next few years. While the aviation industry was given an exemption more than 20 years ago when the EPA eliminated leaded auto gas, a suitable replacement for 100LL has not been found.

A few are in development, including Swift Fuels bio-fuel and GAMI’s G100UL, which the Oklahoma company began developing late last year. Late last month, company officials presented G100UL’s specs at the ASTM convention. The company, which also is pursuing approval of the fuel through an STC for use in a turbonormalized Cirrus SR22, has filed a patent as well.

The fuel, which is all petroleum based, is a fully unleaded avgas, which actually has a lower limit of minimum motor octane of 98.5, said Tim Roehl, who owns GAMI with George Braly. With the addition of some “constituent requirements,” the fuel is a “satisfactory replacement for 100LL,” he said, being careful not to reveal any of the components of the proprietary formula. What he can reveal is that through the patent claim process the company has proved that the fuel “scales up in actual aircraft engine performance rather than down as other fuels are known to do.”

The fuel is also “less prone to vaporize” and is a little heavier than 100LL — about 3% heavier — but will produce more than 3% more energy, which means it will take you farther, he said.

Once approved, G100UL will be a drop-in replacement for 100LL. It can be mixed in any percentage with 100LL, so if a pilot wants to top off a fuel tank that already has 100LL with G100UL, there will be no problem. “The fuel in the plane will still retain its spec and integrity and there will be no degradation in performance,” Roehl said.

Because it is a drop-in replacement, a separate distribution network won’t have to be created — as it would with a biofuel — and FBOs won’t need to add another fuel tank. “We know that FBOs operate on a shoestring,” he said, “so we don’t see them investing in a second tank.”

GAMI continues testing of the fuel in its test cell, as well as in the company’s SR22, while continuing to pursue the STC.

While GAMI would like to approve the fuel through the STC process, the FAA is “hardpressed” for the company to get approval through the ASTM process. “We committed to them that as soon as we have the intellectual property protected, we would initiate the ASTM process,” Roehl said.

A 10-year member of ASTM, Roehl says the “best case” for ASTM approval is two years. “There are no assurances of getting anything through ASTM,” he said, noting, “it is likely we will get the STC done before the ASTM finishes its machinations.”

GAMI officials hope to move the process along a bit faster by inviting key members of the new Avgas Stakeholders Group, a coalition of aviation alphabet groups, as well as petroleum groups, to see the fuel run in the test cell and the airplane. “This gives us a chance for them to ask us the hard questions and we can educate them on what we’re doing,” Roehl said.

For more information: GAMI.com.