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Most planes don't need leaded gas. Jet-A / Diesel etc can also be used in planes. And yes, I understand small, old GA planes may be impacted, but this has been on the radar for decades now.

This comment makes me think you don't actually understand the situation. The vast majority of aviation fuel used IS Jet-A, which does not contain lead.

Small piston engine general aviation aircraft are the only ones that use leaded gas, and most of those can not use anything else that exists currently.

I too have a pregnant wife and a young child, but I worry far, far more about residual lead paint exposure than I do about avgas. Both get tested regularly and show no detectable levels (<2ug/dL), so that makes me feel like the risk exposure is acceptable. Yes, your quote about "no known safe level" is true, but at undetectable levels I'm confident it's in the noise along with all other environmental factors we don't know about.

If you're worried about lead exposure, are you testing?

I'm very happy with the recent progress in GA Avgas. My flying club recently switched from 100LL [1] to UL94 [2] with no appreciable change in aircraft performance.

[1] https://en.wikipedia.org/wiki/Avgas#100LL_(blue) [2] https://en.wikipedia.org/wiki/Avgas#UL94_(formerly_94UL)

There has been no push in the market to get small GA off leaded gas. There has been no extra tax even. As a result, new planes, being delivered today, are shipping with engines requiring leaded gas, which perpetuates this problem.

After decades - does it make public policy sense to still sell NEW planes that REQUIRE leaded gas?

I don't believe so.

Literally every other method of propulsion, some with much stronger claims in terms of life utility, have moved off leaded gas. Ie, the ambulance, the race cars the everything, except GA.

Reality -> GA has a well connected / rich pool of users with influence. If you had a bunch of poor minorities spraying even trace amounts of lead over someone's nice golf course my guess is you'd be getting well off activists to shut you down in no time for environmental or other reasons.

Which airplanes are on the market today that require leaded gas? Specifically which power plants?

Turbocharged Lycontinentals, and higher-compression (9.5:1 or better iirc) stock Lycontinentals.

Within the subset of certified, normal category piston aircraft, you will find one of these two on a sizable proportion of those airplanes.

[1] https://en.wikipedia.org/wiki/Lycoming_O-360

[2] https://en.wikipedia.org/wiki/Continental_IO-550

To my knowledge some ultralights use regular unleaded (called MOGAS in some aviation contexts) and of course anything that you can buy an airline ticket for outside of perhaps Alaska will use jet fuel.

I mean in current production aircraft.

It appears that most versions of the O-360 can run on mogas, or unleaded gas of some sort.

https://www.lycoming.com/sites/default/files/SI1070AB%20Spec...

Indeed, there does appear to be a 100UL drop in out here too.

https://www.aopa.org/news-and-media/all-news/2021/july/27/ga...

I think at least all models of the Cirrus, one of the best selling general aviation planes right now, require 100 octane gas.

To be clear, none require leaded fuel, per se, but until this year there was no approved unleaded 100-octane fuel.

On the contrary, there's now several unleaded options coming to market and now available at certain FBOs. UL94 seems to work well in continental and lycoming power plants that power most Cessna 1XX aircraft. The issue has largely been building the distribution network.

I think he is talking about GA 100L fuel. Which, as someone stated elsewhere, I think absolutely should be changed to 94UL across the board. I don't believe there is no possible way a small single prop GA plane simply cant run on unleaded gas. That seems eerily close to propaganda from Midgley himself. Some performance alteration without some small changes to the plane? Maybe. But cataosrophic outcomes even with some small changes? Highly unlikely.

I think that's because some GA planes still have engines designed 50+ years ago, like O-360: https://en.wikipedia.org/wiki/Lycoming_O-360

Exactly. The idea that you can't make an engine that runs on unleaded is rediculous. Airliners for example don't use leaded.

Yes, planes 50 years ago -> maybe those were designed for leaded. But the idea that we are selling new planes, today, that "only" run on leaded gas is a farce and goes to show how seriously aviation is taking the transition away from leaded gas (which has been delayed as I've said decades).

At some point you just lose patience.

> b) At some point you have to just put your foot down. Ban the sale leaded gas using planes after 1/1/2022. Grandfather in the old planes.

A measure like this may be reasonable.

But C/D totals the entire piston aircraft fleet-- $50B+ of capital equip, plus the whole infrastructure and industry around it-- for only a very moderate change in lead exposure. Best estimates I've seen is that this would lower the total population burden from lead by well under 5%.

Much more sane, IMO, to put in a progressively escalating tax on leaded aviation fuels that over time becomes steep. Then airplanes can gradually transition as overhauls become due, etc, as the pressure from operating costs mounts. Presumably those burning the most fuel would transition first, and an industry capable of retrofitting a few percent of the aircraft per year would spring up.

> Best estimates I've seen is that this would lower the total population burden from lead by well under 5%.

That sounds pretty great actually, for such a simple solution.

It's not absolutely a sure thing that there's any significant burden from aviation. Blood tests come up with a tiny, barely detectable difference near airports (well under 5% for those nearest the airport, and confounded: airports are correlated with low SES and therefore lead paint, etc, is also more prevalent). The most pessimistic estimates from first principles come up with 2-3% of the total population lead burden (more than an order of magnitude above what the blood tests imply, and the blood tests likely overstate the problem).

If you threw a few billion more at leaded paint remediation, I think you'd make much more of a difference. I think the aviation lead problem should get fixed, but because it's such a small part of the overall problem it makes sense to take a graduated approach instead of giving GA businesses the death penalty. Tax leaded aviation fuels, and use the proceeds to pay for leaded paint remediation.

If the tax was substantial I'd support this.

Graduated approach ignores the decades that have ALREADY been provided as an exception to the lead fuel rules that apply everywhere else - it's already been graduated.

> If the tax was substantial I'd support this.

Start at 10% with a commitment to ratchet it up by 4% per year or something. That's enough to start an immediate reduction without destroying the industry.

If you're making choices about engine overhaul now for an overhaul that will last you 7-8 years of light use, fuel costing 40% more at the end of that overhaul will definitely get your attention.

> it's already been graduated.

Doing nothing for decades when it was impossible; and then doing nothing for a decade or two when transition became possible; and then pushing the industry off the cliff is not graduated.

It's a small problem? I read recently that GA accounted for >50% of environmental lead exposure.

Perhaps that's wrong, but I distinctly remember the statistic and it stuck with me.

Source please. All the studies I've read have barely detected higher levels of lead near airports, and are confounded. All the estimates from first principles estimate that it's a very small proportion of population lead exposure, too.

airplanes can gradually transition

Except they can't, since there is no approved alternative.

The other problem is that even planes that can run unleaded gas often don't, because it's not available at the airport. Avgas is a tiny market and because of costs most FBOs can't or won't set up another fuel delivery infrastructure to run two fuels over some short transition period.

Because of this, an additional requirement on a replacement is also that it be safely mixable with 100LL in any ratio, because during the transition period this will happen as people fly from airports where it exists to airports where it doesn't.

This problem is being solved (https://www.faa.gov/about/initiatives/avgas/).

> Except they can't, since there is no approved alternative.

There's an increasing number of diesel engines for GA aircraft, and supplemental type certificates to retrofit them into the same. If 100LL got more expensive, you'd see more people opting for the diesels when an engine reaches the end of its life.

e.g. http://www.continentaldiesel.com/typo3/fileadmin/_centurion/...

Yes, it'd be really cool to end up with a lower-lead fuel that's safely combined with 100LL. That's been "imminent" for the last 25 years.

The poster above advocates for a "rip off the band-aid" approach. GA advocates for a gradual, painless transition that, in practice, will never happen. Surely there's some middle ground?

A post further down says that the first unleaded replacement for 100LL was actually just approved.

Swift UL94 has been to market for 3 years with very low uptake.

Because as far as I know the engines must have their type acceptance updates to reflect it's allowed use.

3 years is also basically a second at the speeds GA changes at.

Yes, technically speaking.

Swift charges $100 for a STC, and has coverage of two thirds of the GA fleet.

Really, all that needs to happen is an airport needs to decide that lead free is important to them and they'll pay the premium for Swift's fuel.

The slow uptake has more to do with it just not being all that available.

Yup-- why should an airfield bother with going to 94UL when it's more of a hassle (some planes can't take it, all planes need an STC).

But if you taxed the crap out of lead-containing fuels, I suspect more would be interested...

Fair enough, but that's not a replacement for 100LL since not all engines can use it. It's gotta be a pretty large FBO to have enough market to pay for setting up a distribution for UL94 in addition to 100 octane gas. Like, there are engines that were certificated to run on 80/87 avgas but no one sells that any more either. Today's avgas market just isn't large enough to make it worth offering two fuels.

About 2/3rds of GA has an STC available to burn it.

There's not going to be one single tidy drop-in solution for the entire market. That's why we should tax leaded fuels, and everyone can pick the appropriate solution for them. Some will pick diesel conversions. Some airfields will go 94UL and people will purchase STCs. Presumably some other people will take other paths. And those with the hardest time transitioning can instead pay the tax and burn leaded fuel, still.

Continental diesels still have "TBR" (time between replacements) instead of "TBO" (time between overhauls). That's a huge problem preventing their uptake.

Well, plus the fact that a new aviation engine runs $30-60k, which is about what an old, small, airplane is worth. It just doesn't make economic sense to replace those engines, you're effectively just trashing those planes.

https://www.aviationconsumer.com/aircraftreviews/aircraftste...

Data seems to imply that the diesel engine lifecycle cost is slightly better now than conventional engines, so electing for a diesel replacement instead of a conventional engine overhaul can make sense... but it's a razor thin difference.

If you made leaded fuels more expensive-- more airfields are going to want to move to UL94, and more people at overhaul time are going to go the diesel path, and the problem will gradually get better.

I was a child in a major city when leaded gasoline was prevalent and I live by an airport now. I probably see as many propeller airplanes in a year as I did automobiles in 5 minutes as a child playing in the street. This is also comparing an airplane off in the distance to a car running a few dozen feet away. So perhaps your recommended ban wouldn't move the needle at all when it comes to blood lead concentrations.

Or perhaps this is the benefit of having younger people in government. Because 50 year old like me thinks "massive progress made, don't waste time on diminishing returns" by comparing the current situation to the distant past. Whereas someone younger sees the threat differently.

Frankly, the propellor airplanes I do see are mostly military which will likely not be impacted by any regulations. I am also making the assumption only propellor airplanes could be using unleaded gas.

Military propeller airplanes are almost all turboprops and do not burn leaded gasoline.

edit: perhaps "all", not "almost all", in the US.

Damn, it makes so much sense that aviation fuel is leaded. I have been a fortunately healthy person for my life, but at one point I lived downtown San Jose (which for the non-locals has an airport in the middle of the city), right under the main landing/takeoff path. I got sick 6x a year or more. After 1 and 2/3 years, I realized that it was probably the planes and moved away, and now I haven't been sick since except maybe once or twice (over 3y).

Just awful.

It's unlikely to have been a direct cause given the (relatively) low levels of lead avgas generates, but it almost certainly has some effect.

The question is, given that it's so clearly a poison (maybe a top 10 poison) - why spray it into the air above residential neighborhood?

Lead impacts are around things like "anaemia, hypertension, renal impairment, immunotoxicity and toxicity to the reproductive organs. The neurological and behavioural effects of lead are believed to be irreversible."

Reality is measurable increases in lead concentrations in blood near airports is very small. But does look like it exists.

Large airplanes/jets do not use leaded fuels. Only small piston planes. Even right under the takeoff path, aviation lead exposure would only be a moderate proportion of your total lead exposure.

Interesting, I see what you are saying. Well, I guess aviation fuel byproducts aren't great to have sprayed on your home every day either way :)

While it's unlikely that you had significant lead exposure due to this as others have pointed out, I also wouldn't discount your issues with getting sick more often, particularly if it was upper respiratory illnesses - people who live under airport flight paths are exposed to up to 4x as much harmful exhaust gas byproducts, superfine particulates, and other nasty particles* vs baseline.

It's amazing that airports aren't required to purchase and relocate the (typically poor) people who are absolutely getting their lifespans shortened by living near an airport.

*(https://pubmed.ncbi.nlm.nih.gov/32639745/)

Most airports, at the time there were built were located in a relatively remote area. The city typically moves closer to the airport, not the other way around. It would require an unreasonable amount of foresight to buy out all this (at the time quite empty) land ahead of time.

Only piston engined planes used any fuel with lead, virtually no commercially operated flights use piston engines (sightseeing and bush pilots aside), so the vast majority, basically 95% of traffic in the skies is already using Jet-A, which does not contain lead.

Wait until you read up on Toxicologic Assessment of Jet Fuel which covers mostly JP-8, the military stuff, but it is also used in trucks, because they can! Or Toxicologic Profile of Jet Fuel which also covers the civil stuff, Jet A.

No Chemtrailer here, btw.