[zodo123]

Private aviation in the US is still, somehow, allowed to use leaded avgas for small planes. It’s a small market but still enough to have an impact on the communities near airports. The FAA has shown little interest in the impact of the problem, and one can only hope the EPA will step in at some point. https://www.nbcnews.com/business/business-news/leaded-gas-wa...

[toomuchtodo]

Post: "FAA, do your damn job"

https://news.ycombinator.com/item?id=30943466

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

Can your Congressional rep and the FAA and ask why this isn't done yet.

[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.

[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.

[thetinguy]

It’s especially crazy because because all the major engine manufacturers have already certified many of their leaded gas engines for high octane unleaded. Some of them are just waiting on FAA rubber stamps. https://www.aopa.org/advocacy/100-unleaded-avgas

[imoverclocked]

“Allowed”… I think you mean “forced.”

If you have to fly certain small planes, there is no legal alternative in most places.

[shadowgovt]

Correct. The FAA is set up to be default quite conservative (small c... "Reluctant to change things without a lot of work"). This makes a lot of sense given what they do (an amortized cost to public health over decades is a lot less likely to get people fired than a private plane falling out of the sky into the middle of an elementary school because the engine failed mid-flight due to a new fuel changing the mean time between failure in an unexpected way), but it does mean that even when things are understood to be safe and proven safe, simple inertia can keep the FAA from certifying them until someone lights a damn fire under them.

Although on this specific topic, I almost wonder if you could make a case that the unleaded avgas is safer not for public health, but for the private pilot and therefore the public in terms of the FAA's main understanding of safety (IE don't let planes crash). How much is a pilot's reasoning capacity compromised by chronic lead poisoning due to the necessary handling of avgas and breathing in fumes that they must do in operation of their plane?

[AnIdiotOnTheNet]

Who is forcing them to fly this plane? I'm going to have to side with the rights of the people to not have lead dumped into their air over the right of someone to fly their own plane.

[cpncrunch]

Air taxis, fire suppression, medevac, flight training, search and rescue, geomapping, aerial application, police, etc.

Very few of these high compression, high HP planes are flown by people just "flying our own plane". Most of us fly small planes that can easily burn unleaded.

[AnIdiotOnTheNet]

You can understand my confusion when GP specifically says 'private', that doesn't immediately call to mind fire, police, and medevac.

The rest don't sound like particularly good reasons to keep showering people with lead.

[_moof]

s/private/piston/

[Melatonic]

I thought we had an alternative gas that has been produced and works but is just not yet fully certified and tested?

[funkaster]

that is the definition of "no legal alternative"

[Melatonic]

My bad - should have restated that - I thought it was certified for a lot of planes and airports but not all (that it can potentially be certified for) and that there is a lot of potential there as a fix

[geoffeg]

Don't most of the more popular aircraft have STCs that allow them to run on automotive gas?

[sokoloff]

It covers about 80% of engine models, but only about 30% of total fuel purchased for those engines per year. (The high power airplanes fly more hours per year, resulting in a large spread between “engines” and “gallons per year” eligible.)

[iamtheworstdev]

1. The "MoGas STC" costs money per plane to buy

2. It only applies to low compression engines, which is a lot of engines, but which also rules out most airplanes made since the 70s. There's a few exceptions, but not significant in terms of manufactured numbers to matter. (the STC you're likely talking about is the one that let engines run on 80 octane)

If the MoGas STC mattered then pilots would have adopted it because rec fuel (ethanol free gasoline) is significantly cheaper than AvGas

[sokoloff]

1. The cost of the STC rounds to $0. I think when I started flying it used to be $1 per horsepower; it looks like it’s still under $1000, which represents no barrier.

#2 and the low availability of mogas at airports is the reason for a lack of adoption fleet wide.

[iamtheworstdev]

re: #2... because... ? Because they aren't going to stock a fuel that only applies to a handful of airplanes. The demand for it is near nil.

[sokoloff]

Exactly. You can barely sustain a fuel farm on the fuel that services 100% of the piston GA fleet. It's incredibly difficult to make the economics work to add a second fuel farm that serves only 30% of the gasoline sold, cannibalizing sales from your other fuel farm.

That's the premise/promise of G100UL: it can serve all the spark-ignition piston aircraft.

[mcronce]

Demand would be a lot higher if the leaded alternative weren't allowed.

[buildsjets]

In addition to the above, the STC requires that automotive gas with 0% ethanol be used. In many parts of the country, that is extremely difficult to find. In my area, the only place to buy it is one farm co-op that is way out in the country. In some places, it is not available at all. Luckily there's a website to find it, but places that carry it have been getting fewer and fewer. So the MoGas STC is not a long-term 100LL workaround.

https://www.pure-gas.org/

[colechristensen]

I'd like to see a risk comparison to measure the effects of living near an airport with heavy avgas users in units of tuna-sandwich-equivalents per month.

Yes exposure isn't zero and effects from that exposure aren't zero, but let's get a good idea of how big the effect size is, because it really seems like some people have an out-of-proportion idea of what the risk actually is.

I'm much more concerned about the heavy metal exposure from nearby coal plants than I am by general aviation fuel.

[MaxBarraclough]

It's detectable, [0] but it's not the top cause of lead poisoning. That honour goes to lead-based paints. [1]

[0] https://news.sccgov.org/news-release/study-commissioned-coun...

[1] https://en.wikipedia.org/wiki/Lead_poisoning#Paint

[sfblah]

I agree with this methodology. People should use a different sort function for their outrage. It's like how people fail to compare the number of cancers caused by radioactive release from coal plants vs nuclear plants. The latter seems like it would be more of a problem, but actually the former is far far worse.

[535188B17C93743]

What do we want? G100UL! When do we want it? As soon as possible!

[MaxBarraclough]

Until then, here's a good podcast episode interviewing George Braly, the man behind G100UL. [0]

Incidentally I recall a later episode mentioning that a couple of decades ago someone was able to get an unleaded fuel approved for aviation in, iirc, Sweden. Unsure why that didn't get much traction.

[0] https://aviationnewstalk.com/tag/unleaded-fuel/

[_moof]

Surely you mean "as soon as practicable." :)

[TedDoesntTalk]

Lead byproducts are spewed all over the neighborhoods surrounding small airports.

[giantg2]

"an area where 2.5 percent of children under 6 years old who were tested had detectable levels of lead in their blood"

"The presence of this fuel means the areas near these airports are often inundated with tiny lead particles"

I agree that we should find lead free alternatives (some exist, so it sounds like this is purely bureaucracy). There's really no reason to keep using it.

That said, it seems there is some fear mongering going on in this article. If the air is truly inundated, why is it that only 2.5% of the kids have a detectable level? If it's in the air and everywhere, then it should be detectable in vastly more children in that area. The biggest question in my mind is, why is this area so low when 50% of US children have detectable lead levels?

[Melatonic]

There is finally a replacement gas being developed / made so we might actually be rid of this crap soon while still keeping private aviation alive