The FAA is now reportedly investigating reports of damage to aircraft related to their use of GAMI's G100UL unleaded fuel in California. Inspectors looked at several planes involved at Watsonville Airport south of San Francisco. Various incidents of peeling paint, leaking fuel tanks and even a bent pushrod/siezed valve have been reported in various forums.
Getting more real world experience with G100UL is a good thing. I have the GAMI STC for my Maule but I haven’t run any G100UL since it’s not available in my area. Although GAMI did a huge amount of testing, running G100UL in a larger variety of aircraft, engines and flight operations over time will allow them to fine tune the fuel formulation, if necessary. I would like that to happen before I actually run G100UL in my Lycoming engine. I’m not worried about the manufacturer not honoring the warranty since my engine is long out of warranty. Most GA engines are out of warranty. According to the FAA, the average age of 150,000+ GA aircraft is over 50 years. We MUST get rid of the lead in aviation fuel just like we got rid of it in automobile fuel, which didn’t happen overnight. Getting G100UL into widespread use and closely monitoring engine health is the best way to gather more data about its effects and how to adjust the formulation to prevent engine damage. Instead of taking potshots at GAMI’s fuel effects, we should be trying to help them make it safer.
The difficult part now will be separating out all of the normal wear and tear aircraft go through from the issues that are actually related to the fuel.
It took the EAA from 1964 to 1982 (18 years) to convince the FAA it was safe to run mogas in an airplane. To this date, there are numerous airframe/engine combinations that do not qualify (eg PA28-181/O360). Petersen has expensive fuel system modifications to get PA28 STC and each airframe engine combination has to be tested before the FAA approves an STC for the airframe/engine combination.
There shouldn’t be a surprise that things might come up with a blanket STC for all airframe/engine combinations unless GAMI has tested all of the many hundreds (or more) combinations, some with post factory mods themselves. I’m glad they’re doing the big experiment in California and not where I am.
Casting aspersions is not productive. We are going to have to move to unleaded fuel and taking the Luddite approach is not productive.
The big problem with these reports is determining causality. Peeling paint and staining is probably more of an issue with old and worn-out paint than anything else. Valve sticking is a long-time issue with Lycoming engines. Suddenly introducing an unleaded fuel at 1000 hours into a Lycoming engine and then blaming the fuel for a stuck valve is unreasonable. Did you do the wobble test before switching fuel? No? Huh.
So, let’s focus on light instead of heat. GAMI seems to be doing that. They have put more effort into fuel and combustion in aircraft engines than anyone else I know of. I really would like to see them taking the lead (unavoidable pun) on this. They know what they are doing. Joe 6-pack pilot, uh, not so much.
Luddites trying to blame their poor maintenance on something new. Lawyers licking their lips; a very American problem.
Lead is bad for people and engines; we know that.
The Fuel companies and distributors don’t want to lose the extremely profitable 100 octane fuel market, so they encourage this kind of nonsensical attack!
Anyone who has ever tried to roll out a new product to the market knows that, no matter how much testing you do, there will be some wrinkles and issues once you go public. Just ask Swift Fuels about that. As Brian1 said, it will be a challenge to determine whether any problems are truly related to the new fuel or just an incipient problem that suddenly appears. To be truly scientific, a pilot considering the switch to G100UL, or any other upcoming unleaded fuel, would be wise to thoroughly inspect his engine and fuel system to see if there are any issues brewing prior to the switch.
As one who has been at ground zero (Reid HIllview) since the battle to close the airport started in 2016, and lead became the PR Weapon in 2021, it is important to remember two very important things. First, while not lovable, lead in Avgas is not killing people or harming kids, as it remains nearly undetectable relative to other sources of airborne lead and lead stirred up from the ground. And second, the unleaded Avgas race is like Betamax v. VHS with two companies competing to be the standard, using very different formulas. GAMI came out of the blocks first, by skipping a lot of testing, and Swift is catching up, with a product that has no signs of airframe or sealant/plastic damage. 2025 should be the year a winner emerges, and the drama will die down as the complexities of rolling out unleaded avgas progress…
First, it’s inaccurate to say that GAMI “skipped a lot of testing”, when that testing took place over 10 years. The FAA doesn’t just assign widespread STC approval without a lot of engineering data to back it up. G100UL is probably one of the most tested aviation fuels on the market.
Second, there were “no signs of airframe or sealant/plastic damage” for G100UL until it came to market, so who’s to say there won’t be similar signs of concern when 100R eventually makes it to wide-spread market?