While the government begins its testing of four potential 100LL replacements, George Braly and Tim Roehl of General Aviation Modifications Inc. in Oklahoma just finished up yet another test of their unleaded 100-octane avgas — G100UL — at Embry-Riddle Aeronautical University.
The fuel underwent flight testing and engine block testing in one of the school’s carbureted 172s.
“No issues were found,” Roehl reports. “We just lack a couple of other tests to complete our first STC on the 172.”
Four years and millions of dollars into development of G100UL, Braly and Roehl chose not to submit the fuel as a potential candidate for the PAFI testing, noting they were “already far down the road to completing the STC.”
Once the first STC is received — Roehl hopes it will be in the next year — it will be followed by a growing list of engines and airframes approved for the unleaded fuel.
Roehl explained it is a two-step process, technically called Approved Model List Supplemental Type Certificate (AML-STC). The first step is a list of approved engines, while the second is a list of approved airframes. “If your engine and your airframe are on the list, you can use the fuel,” he explains.
The fuel will be a true drop-in replacement for 100LL, according to GAMI officials.
That means the only change to your airplane may be a placard or a supplement to the flight manual, according to Roehl.
“There will be no operational changes needed,” he says. “There is no limitation in mixing the fuel with 100LL in any percentage. This will hold true across all engines and airframes.”
GAMI doesn’t plan to go into the fuel production business, but instead plans to license the formulation to producers. According to Roehl, there already has been interest in producing the fuel, with all parties just awaiting STC approval.
Unlike some of the other alternatives to 100LL, GAMI officials believe pilots and aircraft owners will find a “high comfort level” with G100UL.
“It’s very similar to 100LL,” Roehl says, noting it is “petroleum based.”
However, GAMI officials won’t divulge exactly what’s in the fuel, calling it a secret formula akin to the secret formula for Coca-Cola.
“There is nothing in it that hasn’t been running in airplanes in the past,” Braly says.
“And the FAA has been exceedingly thorough in testing it,” Roehl continues, noting that many of the tests this fuel has already been through is what the PAFI fuels are now facing.
“The fuel works great and we don’t expect any issues with it,” he says.
So when can you expect to buy G100UL? That’s unknown until the STC is approved.
“It all starts with approval,” Roehl says. “Once we get approval, things should move faster.”
For more information: GAMI.com