[gengelbro]

This might be my hobby horse, and I've commented to this effect a few times in the past, but here goes:

Hobby aviation still uses leaded fuel and this is detectable near regional airports. The primary reason for this that the vast majority of the existing fleet is stuck in the 1970s essentially as new airframes and engine designs are expensive and viewed as risky.

[sokoloff]

It is risky without a drop-in fuel.

There is a significant, recent milestone on the journey here: https://www.avweb.com/aviation-news/faa-approves-600-engines...

That accounts for around 25% of the gallons sold per year, but the underlying engineering is in better shape than that first step regulatory approval indicates. (The fuel has been running in the test cell and flying in the higher-powered, tighter-margin engines for years already with the airplanes in the experimental-R&D category.)

[gengelbro]

A huge amount of this, "spraying lead on your head" is not for training or any similar purpose, but for amusement.

[edrxty]

The vast majority is flight training, fulfilling currency requirements and commercial operations (135 charter ops, survey and similar, fire fighting, etc.)

Most of the pushback against lead free fuel is actually from the commercial operators that consume the vast majority of the fuel and operate higher compression engines that need the octane boost normally obtained with lead. The recreational side could have switched ages ago if not for the shared infrastructure. The recreational part 91 side is already increasingly using automotive gasoline through newer engines (rotax 91x series), increasingly common EAB airframes and mogas STCs. Given that auto gas is half the price in most areas, the cost sensitive recreational market has already been moving in that direction.

[gengelbro]

> The vast majority is flight training

Can you substantiate that claim for me? I've never seen a breakdown, since you've claimed 'vast majority' perhaps you know better.

[kayfox]

https://www.faa.gov/data_research/aviation_data_statistics/g...

These stats sorta disprove the OPs comment, but I think these stats kinda bury how a lot of personal flight time is also for currency and flight training, as a lot of pilots schedule personal trips to maintain their currency.

Also to note is that a lot of General Aviation is a pipeline for airline pilots and in countries where there is not such a strong general aviation industry there are higher accident rates.

[gengelbro]

This implies the _vast majority_ is precisely the opposite. With ~75% being personal use.

[edrxty]

The FAA just approved a blanket lead free replacement. It's still being rolled out but it shouldn't be an issue for much longer.