[CloudHound]

I thought this looming problem might have figured on the Forum by now.

International standards are changing so this additive will be banned in the not too distant future.

By coincidence I used to be able to see the only factory making this stuff from my first home in Cheshire.

The bigger the motor the bigger the problem I believe.

[JodelDavo]

Interesting.

Wonder what the Americans and Canadians will do for their fleet of big heavy piston aircraft that NEED 100 octane fuel?

Fortunately my aeroplane will run on UL91 so not particularly worried but feel for the big piston & warbird operators if the green lobby get this through

[CloudHound]

I think it’s through the lobby and into the reference library.

[riverrock]

There is no agreed timeline and no working alternatives for high compression engines.

Once there are feasible alternatives I can see it happening. Until then - no.

[GrahamB]

I understand that someone queried this with EASA, who responded that there is no immediate short term threat, as the concentration of TEL in Avgas is below the threshold for the initial legislation.

In the longer term, it remains a concern.

[Human Factor]

UL102 will likely be a solution but it’s still under development.

[neilmurg]

AFAIK there were 2 companies developing a replacement and a big test program. Shell and Swiftsomething? It seemed to hit a problem/pause and the implementation cycle was put in doubt. The sooner the better IMO.
I've said before if you CAN use UL91, I think you should. Other less correct opinions are available.
The use of TEL appears to have been driven by its patent-ability, whereas alternatives weren't. Despite the fact that it was known to be extremely poisonous, esp. for children. Midgley (who profited from it) went on to make money from CFCs... I take little satisfaction from his accidental demise at the hand of one of his own inventions.
UL102 will be EXPENSIVE, but it's development has been accelerated by the lack of takeup of UL91, the reasons for UL91 relative lack of popularity are complex.

...EU said...the concentration of TEL in Avgas is below the threshold for the initial legislation...

around 5 times the amount that was in 4* I think

[Lefty]

This qualifies as one of those potential issues that is completely beyond my influence or control. It is therefore a complete waste of energy worrying about it.
Either a solution will be found - and I can keep flying, OR,
No solution is found - and the value of my £60k 300HP aircraft will drop to about £500 scrap value.

[skydriller]

the reasons for UL91 relative lack of popularity are complex.

Really? I thought it was because it isnt any cheaper than 100LL...

[neilmurg]

the reasons for UL91 relative lack of popularity are complex.

Really? I thought it was because it isnt any cheaper than 100LL...

Well generally more expensive, but more 'worthy'. What price do you put on environmental / health concerns? I'm using UL91 when it's ~20p more expensive.
I heard of a field that stopped supplying it that ordered it's flight school to use it up. Why weren't they using it anyway?
It's usually the same price, IMO the engine runs cleaner, fewer mag drop issues. (High compression engines can't use it). The issue is aircraft that CAN use it choosing not to.
Airfields have to gear up for the ground infrastructure to offer another fuel (expensive), which reduces the sales of their 100LL, which can increase the price (unpopular).
When the price of fuel drops, if your UL91 is a slow seller, you can't drop your price until the next shipment.
Some people won't use it because 'the engine works with 100LL, I won't risk changing to UL91'.
If it's not available everywhere, it's easier to stick with what you know.
There's only 1 refinery to get UL91 from in Europe (France. And there's only one TEL manufacturer, in the world, the UK. AFAIK)
So, complex

[neilmurg]

It would be nice if a few people said 'Oh, good point, we'll start using UL91'. But so far, nothing... PA28, Cessna150/172/180, loads of training aircraft )360, IO360, 320 and on and on and on, remember this when GA and fields get shut down/sold. What do we do to stay relevant? This is an inflection point. We can relatively painlessly make a difference, if we have the brains, conviction and skill to address global warming, sustainability and the continuing viability of the planet.
No? Just me?
And I'm rubbish as well, I have no excuse.

[Paul_Sengupta]

The 200hp IO-360 can't use UL91.

[johnm]

Our IO540 can use either but needs different engine oil for UL91, we'll swap when UL91 becomes ubiquitous.

[Bathman]

Out of the 3 airfields I kick about two of them have UL91. At all these airfields the flying schools represent 90% of the fuel used. All the spamcan schools fill up with AVGAS as its alwasy the cheaper. The only exception being the microlight schools one of which uses the UL91 the otheruses mogas brought in jerry cans.

All the flying schools aircraft can use UL91 and I very expect if that was the cheapest then they would you that.

[skydriller]

All the flying schools aircraft can use UL91 and I very expect if that was the cheapest then they would you that.

Exactly what I was saying. We all know the tight margins the schools operate with. You fill up with 100ltrs and its 20p cheaper thats 20 quid. Its not rocket science.