[nimbius]

as a diesel engine mechanic ive always figured there was some amazing conspiracy about leaded avgas. Here on the ground, diesel regulations and formulations are basically a yearly theatricality. new scrubbers, new regenerators, fuels you can use and fuels you can never use, and special locations and applications for the fuels if you use them at all. The regulations are pretty rigorously developed and enforced.

[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.

[dghlsakjg]

Its not so much a conspiracy as just not as big of an issue compared to diesel consumption

About 11 thousand barrels of 100ll are produced every day in the US. Compare that to 4.9 million barrels of diesel daily, and you can see why it is a bigger priority. In this case 100ll is a literal drop in the bucket.

But also its a rich guy hobby that generally isn't very visible.

[colechristensen]

If your standard diesel engine fails it’s generally not a life threatening emergency though so change is much safer. Aviation has safety and regulatory habits written in blood.

[ethbr1]

Aren't most emergency backup generators diesel?

Hospitals. Nuclear power plants. Airports. Laboratories.

[mschuster91]

These are multi redundant and generally hospital patient monitoring systems have additional batteries of their own to make sure people don't die, and in the case of a major clusterfuck there are emergency procedures in which it's specified how power will be restored assuming a grid and backup generator failure (usually it involves the fire department shuttling a generator pack to the hospital site).

With engine failures in aircraft however, the consequences can be way more dire - particularly in GA where it's (at least in the US) even being allowed to fly without a license at all (Part 103 ultralights), and forget about regular legit simulator training on what to do in that case.

[AdamJacobMuller]

It's very easy to run emergency backup generators in parallel.

Take your total load (10MW) divide by 5 (2MW) and you need 5 2MW generators, buy 7 and run 6/7 and your "down for yearly maintenance" generator can be offline while your "oh shit we installed the wrong fuel filter and the injectors clogged" generator also fails.

Much harder in a plane.

[lazide]

Especially since rarely does anyone care about how heavy the emergency generators are. But if you add 100 lbs too much in the wrong place on a GA plane, everyone is almost certainly going to die.

[dghlsakjg]

Yes, but the GP is posting about diesel engines in over the road equipment.

Those regulations don't apply to 1. existing installations in trucks or 2. generators.