UL94 / 94UL - what is it and where does it exist?

The January 2017 Sport Aviation has an article on UL94, starting on page 26.

I know this is an old thread, but the Socata forum has recent reports of people in the US starting to see this fuel at their fields and have used it without issue. Does this have any legs in Europe, or does the GAMI project make it irrelevant?

Peter wrote:

needs the purchase of a type specific STC.

UL94 is covered by the ordinary Petersen Autofuel STC, so the need for a special STC is related to the special Socata/TB situation?

Peter wrote:

For a TB-20 the price is around $400 for the STC.

EASA allows use of alternate fuels without aircraft certification/STC. It is in the Standard Changes CS-SC202b and SC203b. It just requires the engine to be certified, not the aircraft type. According to Lycoming service letter SI1070 the IO-540-C is approved for UL91/94 and Hjelmco.

I thought that UK CAA still followed EASA Certification Standards? If so, STC for this should not be required in the UK.

Isn’t this the most powerful engine presently certified to run on anything less than 100LL?

I think Peter was referring to 100UL…one can buy STC for engine/airframe

Unrelated to 91UL/94UL ofc

This is strange. I was going to link to the reference for the above mentioned CS, but then I remembered something.
What is absolutely true, is that FAA requires an airplane STC to allow certificated a/c types to use other fuels than what they are certified for – whereas EASA seem to be a little smarter and allows the aircraft to run on alternate fuels that the engine is approved for. At least that is the case for UL91.

Last autumn my home airport EKRK announced the coming of UL94 as they had talks with a supplier. Then nothing happened, and there was no word from the airport. Then I remember someone mentioning that EASA had forgotten to include UL94 in the UL91 standard change. AFAIU, those fuels are variations of the same fuel specification, with the UL94 being the less restrictive seem from the engine’s point of view. Indeed the Lycoming fuel approval list does not list one single engine type that is approved for UL91 but not for UL94. Indeed the EASA standard change CS-SC202b is about UL91 and does not mention UL94.

So, when EASA allows the use of UL91 and not UL94, this supposedly is just due to an oversight. Which should be the reason that my airport suddenly stopped talking about UL94. And a good reason why UL94 is not widespread at all in Europe.