[Gibbon1]

I remember conversations about using unleaded gas in aviation 40 years ago. And the pro side's argument is auto grade gasoline is highly regulated with better quality control and standards than leaded aviation gas. And pointed out that cars run just fine at the altitudes light aircraft fly at. SO I hear you on that. It's a bit inane.

If there is a conspiracy I suspect it's the government exerts a light hand on things rich people do.

What surprises me is the refineries didn't tell the light aviation industry they weren't going to make leaded gas anymore. If they'd done that the Feds would have kicked them some cash to develop an unleaded version.

[mauvehaus]

Apart from specialty applications, auto engines run at a small fraction of their full power output the overwhelming majority of the time.

Aero engines run at a substantial fraction of their rated power output basically full time[0].

The fact that auto engines can be run on unleaded, lower octane gas at 10,000' or more doesn't really tell us that the same low octane unleaded gas is suitable for an aero application.

[0] And in some cases are rated for more power for limited lengths of time such as takeoff. See here, for example https://medium.com/s/story/the-long-way-round-the-plane-that...

[jefftk]

> What surprises me is the refineries didn't tell the light aviation industry they weren't going to make leaded gas anymore.

You can just add lead to unleaded gas (which was legal until 1996 in the US), so even if you could convince them to be altruistic in this way others could just work around it.