Kind of needs a caveat: ... for engines not designed to safely operate with other fuels. I.e. it's not that we need Avgas 100LL to make piston-engined planes possible, we just have a lot of plane engines around that need it. (and one can argue that industry has sat on the problem a bit, because why change as long as 100LL is readily available. (and making 100% compatible fuel replacements indeed appears to be difficult, as far as I know there is only one that has any kind of permits for one plane type, and that also has somewhat nasty additives - so changing the engines is the thing to do)

Its almost entirely small hobby planes 2-4 passenger. Almost none of those planes have any real reason to still exist. Its basically rich or upper middle people that don't care they are literally poisoning people while they tool around with their hobby.

You're not entirely wrong. Aviation is a hobby that is difficult to engage in if you don't have money. But flying those same planes is exactly where your commercial pilots are trained. It takes 1500 flight hours (certainly this number is wrong but too lazy to look up the current ATP minimum) to be eligible for the license to fly passengers on commercial airlines. A substation portion of those hours are as paid instructors.

Interesting. So basically the large airlines are skirting the poisoning issue by essentially passing it off to tiny training companies? Kind of like how we "recycle" our electronics by shipping them to a poor country.

Small single engine planes == hobby? No. The vast majority of the hours flown in these planes are for commercial purposes. If you are going to focus your ire anywhere - it should be on these money making enterprises that don't (have to) upgrade their infrastructure.

The negative externalities of your passions, your work, your hobbies, your personal life are currently poisoning thousands of people. You are currently typing on a computer built with rare earth elements mined in poor countries with slave labor. You probably eat shrimp on occasion, literally harvested by people forced into literal slavery, trapped on a boat. You likely enjoy looking at and thinking about crypto, which is currently mined with massive amounts of compute powered by coal plants, which emit far more toxic byproducts than any amount of general aviation.

No one is a saint. Regulating away all the hobbies out there to minimize the impact would probably result in some sort of violent revolution, if it could even be done.

I get your point and mostly agree. However you would struggle heavily to find even one thing that 99.999% of people do that remotely compares to literally flying in the air spraying lead poison over hundreds of miles and thousands or tens of thousands of people, animals, plants that are in your way.

Its like saying lets just make all bombs nuclear cause they kill people either way. One of these things is much, much worse and can be addressed but of course will not 100% solve the problem.

How is avgas poisoning people?

via the leaded gasoline it uses. Same as how leaded gasoline in cars poisoned people. Same premise, different vehicle.

From the exhaust or skin contact?

Both. Though I am not sure but I think you have to ingest it but having it invisibly sprayed all over your skin makes that very much likely.

Thank you.

I myself enjoy hunting humans, as they are the most dangerous of game. Yet I am constantly accosted at my dinner parties, it’s truly intolerable. I don’t see where these people get the nerve to act so holier than thou. We all have our vices.

(/s, obviously)

My gardening hobby does not involve poisoning my neighbour's children. Might be a tad different, pal.

Last summer GAMA received a supplemental type certificate for a 100LL replacement, called G100UL. The STC covers certain Lycoming O-320, O-360, and IO-360 piston engines, which are commonly used in light aircraft.

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

s/GAMA/GAMI/

The blame lies at least partially on Lycoming, who developed a nice engine in the 60s and then apparently fired their R&D department.

This is a little unfair, but only very little. The engines are primitive by modern standards because the company is wildly conservative in their design philosophy. The engines are quite reliable if run within their design envelope and maintained according to the manual, but it requires considerably more maintenance per operation hour than a modern car engine and most modern car engines are even more reliable when properly maintained.

Some Lycoming engines run fine on the right unleaded fuel.

https://en.wikipedia.org/wiki/Avgas#UL94_(formerly_94UL)

Well, they can outlaw operating older private planes. Newer private planes often use kerosene (aka Jet-A) fuel, just like airlines.

But that would be unjust. Imagine your car suddenly gets outlawed.

A version of that for cars is common enough actually. Several countries and US states have road worthiness tests that include minimum (maximum?) emissions standards that must be met. The car I drive will probably ultimately fail on emissions as standards rise over the next few years.

Well, the curious fact is that small planes (Piston General Aviation, what is discussed here) emissions are comparable to cars.

Cessna 172 (trainer plane, not known for efficiency) burns 32 l (8.5 lb) per hour at a cruising speed of 122 knots (140 mph, 226 kph). Assuming no wind, it gives mileage of 14 l / 100 km (16.5 miles per gallon).

Taking into account that there are much less planes than cars, they emit 0.13% of all the CO2, emitted by transportation, comparing to 81% of motor vehicles (623 times less) [1]. So I would say their lead emissions are too low to bother (and mostly harm their owners who are close to the exhausts). Would be nicer, of course, to use unleaded, but not a big deal to lobby for legislations.

[1] https://communicatescience.com/zoonomian/tag/cessna-172/

I live in a county with emissions standards. Vehicles over 25 years old are exempt. There are reasonable ways to implement rising standards by exempting older ones.

I've lived in two places that required emissions testing. In both, the vehicles were held to the standard in place at the time it was built, not the current highest standard.

The larger private planes use kerosene, but smaller planes use gasoline just like they always did.

The difference is that new gasoline planes can work with unleaded.

They could be outlawed non-suddenly.

So many things were making it slowly less and less viable through extra costs/requirements would've likely been the better plan, but instead nothing changes until at some point there is enough pressure for change, and then there's complaints its "so suddenly". (I think with Avgas that has happened a tiny bit through storage regulations - its sufficiently more annoying to keep around that some places don't offer it anymore, making it a tiny bit less attractive for plane buyers)

Then people will just complain it's sudden when it gets close to the deadline.

Even cheap used small private planes cost > $100k. Since they are exclusively owned by wealthy people, it is a political impossibility to outlaw them.

> exclusively owned by wealthy people

You are underinformed. Most Cessna owners I know, are middle-income fanatics, usually co-owning a single plane.

I looked into the cost of flight lessons in a small plane, the cost of using an airport runway, and fuel. It was extremely expensive to me and I make 6 figures.

Then you have very different priorities than an airplane owner. You pay for plenty of things that are extremely expensive, you just choose different things.

I too make six figures, and I don't think I do anything as expensive as completing flight school and co-owning a Cessna. I mean, my house is more expensive than that, I guess, and my car is (barely) more expensive than flight school might be, but surely amateur pilots have houses and cars too. About the only expense I have that might come close to serious flying as a hobby would be pets, but outside of the one time we had to pay for chemo for our dog it's not that expensive.

What was your cost?

In US you can get a license for as low as $8k total. In expensive California, expensive SF Bay Area cost is around $15k total.

You're saying that amateur making six figures cannot find $15k for something they basically live for? Sounds very unlikely.

Btw, there's no cost of using airport runway, it's paid from your taxes.

There is no cost of using an airport runway, at least in the US...

We could buy them up and scrap them as their value declines while also working to outlaw 100LL at the ~4000 FBOs in the US that still carry the fuel. At some point, demand decline encounters an inflection point where it's no longer economically feasible ("death spiral") to continue to provide 100LL fuel to FBOs.

Cash for clunkers sort of thing.

Cash for clunkers was only tenable because the recipients of the cash were predominantly the working poor. Even then, economic conservatives howled at the program for its destruction of capital.

The first recipients were new car buyers. Hardly the working poor.

You could argue those buying new cars bought clunkers from the working poor for their above-market trade-in value, but that only works for the poor if they didn’t need to replace that clunker because everything used went up in price.

Most of the planes flying were made in 60's and 70's. Most of them can be bought below $100K. Most owners of 100LL burning planes are middle class. Wealthy people fly jets or at least turboprops and burn Jet-A.

I think deciding if something is unjust should factor in the impact. If someone has a 1990 Honda Civic that is their only means of getting to work and suddenly it's illegal due to pollution that's one thing. However if someone's private jet needs an expensive upgrade then that's another impact.

Wrong airplane. Jets use JET-A (no lead) not AVGAS

Don’t they need new engines at some point anyway?

Yeah, but you would need a new type certificate if the model of the engine is different from the version that was certified. Not to mention, you'd need a lead-free-compatible engine that physically fits into the plane.

True! But for many popular airframe/engine combinations there are companies which hold supplemental type certificates (STCs) for the conversion, see for instance Petersen Aviation who have a dedicated website for STCs covering conversion to auto fuel: https://www.autofuelstc.com/

I know some enthusiasts have been retrofitting with Subaru boxer engines with some success, but they end up with an X registration.