Textron says it won't add G100UL unleaded avgas to its approved fuel list until it has been more thoroughly tested. In statements released last Friday (one for singles, one for twins), the company said it won't be giving its stamp of approval to the fuel unless and until that more comprehensive testing has been done. It cites the Piston Aviation Fuel Initiative (PAFI) and the Eliminate Aviation Gasoline Lead Emissions (EAGLE) fuel evaluation process, of which it is an active participant, as the kind of "comprehensive testing of candidate replacement fuels for engine performance, materials compatibility, and operational safety" it's looking for.
Fuel must do more than burn cleanly in an engine and produce its rated power output. It must also not react with the installed airframe components, that contain and transport it to the engine. Including things where the inevitable leaks occur. Avweb in a companion article reports that GAMI recommends replacing nitrile components with silicone/fluoropolymer components. If that is indeed the case, and Michael Luvara appears to have evidence that suggests it is so, then the airframe STC should make note of this, especially for legacy aircraft. The FAA has been known to approve things and later issue an AD modifying or even eliminating its Approval.
If Lycoming and Continental are uncomfortable approving G100UL, are we confident they’re doing all they can to validate their concerns? I’d expect them to have two or three of their most at-risk engines (high compression, high HP) running nearly 24/7 on each of the emerging fuels so they can validate or refute their concerns.
From what I understand, they’re not doing any meaningful testing and are just letting GAMI and SWIFT do it themselves and then ignoring their findings.
The cynics out there could conclude that the engine manufacturers really don’t want Unleaded fuel because as we’ve seen with car engines, and aircraft engines like Rotax, the engines run better and last longer on Unleaded fuel suggesting TBOs will increase over time and engine manufacturers will sell fewer parts and engines in an unleaded world. I’d sure love to see the engine manufacturers come out with regular updates to all of us on the results of their extensive testing, but I don’t believe they’re doing that testing so everything just swirls.
Perhaps EAGLE and PAFI can clarify this and advocate for more transparency and intensity in making progress on this.
So; Textron is saying that STC’s are not valid?
So all those STC’s where Lycomings are be substituted for other engines are not valid?
Just asking;
Clarification; please!
“I’d sure love to see the engine manufacturers come out with regular updates to all of us on the results of their extensive testing, but I don’t believe they’re doing that testing so everything just swirls.”
Indeed, sir, that is the case. The obligation to test this, or any other fuel, is not on them. It’s on the maker of the fuel.
Yes, but both SWIFT and GAMI have tested their fuels and found no issues. This has been the basis of the FAA issuing the STCs that they have. So we have a world where the fuel producers and the FAA have said their fuel is good to go based on testing, yet we have the engine OEMs refusing to provide their support based on “concerns” but without any testing-based evidence that their concerns are backed by anything other than simple fear of the unknown.
As an industry, we all have a vested interest in getting to a solution and IMHO we’re as close as we’ve ever been with both SWIFT and GAMI (GAMI is furthest along, but SWIFT is pushing hard and making progress). Given how close we are, I’d expect every OEM to be taking these fuels and doing their own testing and sharing the results they’re getting vs just saying “we’re not comfortable yet” and letting everyone else try to figure out what to do…
“…are backed by anything other than simple fear of the unknown.”
Precisely. A cornerstone for aircraft and engine manufacturers has always been predictability, closely tied to a profit margin whittled away by litigation. Fear of the unknown is a tangible hazard in such cases, and as long as controversy continues to plague the need for unleaded avgas, they will not budge until forced to do so.
I think it’s mostly a question of liability and cost of testing. Textron and Continental don’t want the specter of liability hanging over their heads if there’s an accident due to some swollen part stopping an engine. They don’t want to pay for all the testing either.
It’s also interesting to note that EAA and Petersen Aviation worked toward and acquired STCs for the use of autofuel in relatively low powered engines throughout the 1980s. It was largely a cost reduction initiative. When 80 octane fuel disappeared in 2004 or thereabouts, autofuel was considered a good alternative to the slower and hotter burning 100LL fuel-especially for low output engines. In spite of the operational advantage for some engines, autofuel was not listed as “approved” by Lycoming until July 2010. Predictability takes time.
Where was all these manufacturers and alphabet groups/organizations/committees opposition when they…
-Eliminated lead in auto fuel?
-Switched from 100/130 to 100LL?
-Added ethanol to auto fuel?
-Created the DEF additive to diesel engines?
-Mandated electric vehicles?
But let small private owned companies create fuels and everyone releases the H*ll Hounds…
Obviously, if you’re not a major share holder company you’re not allowed to be in the fuel or transportation business. The United States of America was built by SMALL BUSINESS and I will continue to support the LITTLE GUY.