[dougalm]

Is it worth trying to apply pressure at the local level? I read that Santa Clara County banned 100LL in January.

I have young kids. We live near Hanscom Field and spend a lot of time near Barnstable Airport. Should we try writing our local airports/cities/counties?

At Barnstable Airport, the big operator is Cape Air. They make a big show of being green, so maybe they'd want to be early adopters of G100UL. Does anyone know if the existing G100UL STC applies to Cape Air's fleet? Could they switch to it if they wanted to?

[sokoloff]

Cape Air's piston fleet is Cessna 402Cs, using the TCM TSIO-520-VB engines. Those engines are not on the G100UL STC Approved Model List.

https://download.aopa.org/advocacy/2021/SE01966WI_AML-Amd1.p...

https://gami.com/g100ul/GAMI_Q_and_A.pdf

Adding to the data above some of my personal opinion, which was informed by visiting GAMI's Ada, OK facility, taking the APS course (taught by the GAMI principal engineer), and having seen the fuel demonstrated on the higher-strung TIO-540 Navajo engine: that the 402C's engines would run just fine on G100UL without operational limitations, but as above they cannot legally do that today.

[dougalm]

That's very helpful. Thanks for explaining! It looks like the Lycoming O-540 engines on Cape Air's new Tecnam Travellers aren't on the list either.

I'm glad you think that G100UL should work in the Cessna engines and it's "just" a bureaucratic issue. Do you have any sense of what the current blocker to approval is? I found Paul Bertorelli's AVweb article a bit hard to follow.

[sokoloff]

I can't fairly represent the FAA's point of view here.

I'm not saying that to be cagey; I just haven't spent tons of time thinking about all of the "what could go wrong?" and "why is airplane certification done the way it's done?" It's easy to sit on the outside and say "that's ridiculously overly conservative!" but I suspect the truth is there is a mix of over-conservative and genuine purpose to "until you prove it via certification, it's not certified as true".

Air-cooled engines have wildly varying operating conditions. Airplanes need to take off not just on a 60ºF sea-level departure to a 3000' cruise, but also at a 105ºF departure from 5000' with a direct climb over terrain to 15K feet. The fuel will sometimes be 125ºF after baking in a tank or a wing all day. It might not be on the exact centerline of the specification range. It might be 6 months old and some of the higher volatility compounds present in reduced amounts. High-strung turbo engines with fixed timing live with pretty low detonation margins, especially at partial mixture settings. Pilots rely on the pilot-operating-handbook or airplane-flight-manual for performance calculations with regards to runway utilization, accelerate-stop/accelerate-go distances, all engine climb gradient and one-engine-INOP climb gradient. Any amount of performance degradation that would invalidate those figures is cause for FAA rejection of the STC. Having flown a handful of heavy, hot, and high departures where the ground isn't falling away from the airplane nearly as quickly as I'd like, I can appreciate a certain amount of conservatism here.

So, I have to give the FAA some benefit of the doubt as I'm not an expert on certification topics. I do believe in the technical ability and already completed lab, bench, and flight testing that GAMI has done and the way they've set out to approach the problem, but to be fair and balanced, they've done some amount of "we think the FAA/PAFI process is fundamentally the wrong approach and we're going to go about it this other way that we think is superior." I happen to think they're right, but when you very publicly do that to a government agency who said they want the process to work this other way and you don't participate in their preferred process, I think it's reasonable to expect that you'll run into delays. (Even if no FAA person is acting in the least bit unethically; you're just trying to use a different process than the one they're putting their energy into and even if everyone has the best intentions, that will cause friction and slowdowns.)

[stergios]

There's an old saying that "aviation regulations are written in blood". If there's an FAA rule it most likely came about from the learning of an accident investigation.

[throwaway0a5e]

If I had a nickle for every time some dolt busted out the "written in blood" quip for a rule that had no blood involved I'd be a very rich man.

Lots and lots and lots of rules, especially post 1970 or so are about ass-covering. Post 1980 you get a lot of rules designed to remove human judgement from the equation.

[ericpauley]

Note: this is the current model list. The new proposed AML that the FAA is supposedly about to sign off includes all engines approved for 100LL.

[toomuchtodo]

I would complain to anyone who will listen. The health effects of lead exposure are well known, and a suitable replacement is available. Any continued combustion of leaded avgas is out of apathy and laziness. The FAA is dragging their feet because there is no cost to them to do so.

[hutzlibu]

I know nothing of the technical details, so you are saying, no one would need to change anything with their engines etc and just switch to leadfree gasoline?

[toomuchtodo]

That is my understanding.

https://www.avweb.com/insider/faa-do-your-damn-job/

> To scrub the playhead forward, last summer at Oshkosh, to great fanfare, the STC approving G100UL was announced. It applied to a limited number of engines and GAMI was tasked with additional testing and data work to expand the engine list. This it did. The Wichita Aircraft Certification Office duly sent a letter to FAA HQ reporting that GAMI met all the test requirements—best-run program they had ever seen, or words to that effect—and was entitled to an STC-AML with every single spark ignition engine in the FAA database approved to use G100UL.

...

> At a press conference, Lawrence said he thought PAFI had been “a great success.” I simply cannot agree. I don’t know how anyone in the industry could think this. PAFI was supposed to yield an unleaded drop-in replacement for 100LL. It did not. It was an abject failure and now, even though the FAA has an STC in hand awaiting approval for a fuel that has been proven, ad nauseum, to work in all engines, it wants more money for more testing. While the PAFI program—that was Piston Aviation Fuels Initiative—supposedly produced data, accessing it is all but impossible.

[sokoloff]

Yes, but it's "switch to a lead-free gasoline, but one that is different from the currently sold lead-free gasoline used in cars."

https://gami.com/g100ul/GAMI_Q_and_A.pdf

[ryandrake]

(Disclaimer: am a pilot)

I think applying local pressure (I.e. the Santa Clara approach) will only annoy pilots and get their political associations (AOPA, EAA, etc.) to dig in and fight bans and closures. In general, pilots of small planes desperately want to switch away from leaded gasoline too! We all want the same thing. I have a family that I don’t want lead poisoned, too. But I’m not going to simply stop flying airplanes indefinitely waiting for the FAA to get its shit together.

Trying to get 100LL banned is like those protestors blocking rush hour traffic to advocate for their cause—it is unlikely to be effective, and it more likely just makes any potential allies into enemies.

[dougalm]

Thank you, that's really helpful context. I can easily imagine that failure mode playing out. The last thing we need is for it to become some kind of culture war.

Maybe local pressure would be more appropriate once the FAA approves G100UL for all engines. Then it could be about encouraging airports to make sure G100UL is actually available, and getting airlines like Cape Air to switch over their fleets.

[zenexer]

Not to mention there’s a sizable bakery practically in the airport that ships its bread to stores throughout MA. Leaded bread—yummy.

[giantg2]

Here, let me help you not sleep tonight...

https://www.verywellhealth.com/spice-lead-exposure-5209991

[brimble]

> Brightly colored spices, such as turmeric, chili powder, and paprika, are the ones I'm concerned with more because those are the ones that are more likely to have lead added in as a coloring agent

Holy shit. This is a "the FDA should be coming down on this hard yesterday" kind of thing.