Key things here:
The gas used in the small planes with piston-driven propellers has lead in it. Yeah, the same stuff that was banned from automotive fuel because it causes brain damage in kids.
That lead in the fuel airplanes burn? It ends up in kids blood
There’s a new fuel mix starting to be available which doesn’t contain lead, and which works for all airplanes. It’s available in some places in the US, but not all of them yet.
The FAA has a plan to make going lead-free a requirement by 2031…but right now there isn’t anything stopping airport owners (often local governments) from making the switch happen faster. Only thing which might stop this is that the Republican version of the FAA reauthorization bill contains a requirement that airports keep on selling leaded fuel forever, so it’s also important to stop that from becoming law.
Old airplane engine designs were created assuming leaded fuel, and the slight reduction in horsepower associated with pre-2022 unleaded fuels was a problem for them. So the phaseout is just getting started, with it happening in only a handful of airports to date
But leaded gas in cars was banned in '96. Why has it taken them 27 years to begin phasing things out for airplanes?
Because all those old cars are now off the road or running gutless on unleaded fuel.
But you can’t just run an airplane “slower” or it falls out of the sky.
On the other hand, mmwave radio issues are in these exact same planes, so maybe we should just admit that they’re no longer safe to fly.
Also airplanes live longer and the rich dudes who own them tend to be conservative.
They may also be brain dead from lead exposure.
There was also an argument for valve seat protection afforded by lead gas, but they should eat the cost of engine rebuilds and be forced to comply. Especially as many of those planes are for hobby anyway.
And IIRC, the lead contributed to long term reliability of the engine too, something you definitely want to have in a single-engine plane. You don’t want to switch fuels and end up with Cessna’s falling out of the sky.
That’s a myth.
Only sort of; the engines were designed so that the additives were important to combustion performance. Of course, the solution isn’t to keep using leaded fuel, but to rebuild the engine to be more reliable AND not depend on the additives.
Running an old engine with modern fuel will definitely cause it to fail.
It’s only important for increasing octane. You would have to reduce the performance of the engine on order to prevent knocking.
Not if you’re replacing tetraethyllead with ethanol. Both are used to increase octane, but the ethanol is hygroscopic, absorbing water from the air. If the plane sits with watery ethanol, especially if not designed for it, then corrosion will wreak havoc on the fuel system.