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.

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.

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

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.

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

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)

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.