huv wrote:
Rotax powered fleet (which supposedly are certified for UL94 or has an STC).
AFAIK all Rotaxes are approved for lead-free AVGAS.
Here at EKRK, Shell has a truck with UL94, for almost 2 months now. They are selling to one operator only, apparently only to their Rotax powered fleet (which supposedly are certified for UL94 or has an STC).
EASA says UL94 will be included in the next CS-STAN revision, but as late as 5 months ago EASA expressed doubt as to whether any UL94 was available anywhere in its area. I have tried to contact EASA to make sure they know, but have not managed to get through yet. They really should publish the revised SC asap.
UL94 is about 7% cheaper than 100LL here, according to Shell’s price list from June 1st.
In engineering terms, approving just an engine makes no sense, in the current climate of dodgy fuel add-ons.
Silvaire wrote:
It doesn’t seem so smart when the engine as installed on a particular airframe quits due to vapor lock.
Exactly. That’s why EASA only gives blanket approval for some alternate kinds of AVGAS and not for auto fuel. That still requires an airframe STC.
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.
It doesn’t seem so smart when the engine as installed on a particular airframe quits due to vapor lock. There was a reason that some aircraft types were unable to get an auto fuel STC.
At least that is the case for UL91.
Which is 100LL without the lead and therefore one needs only worry about the octane requirement of the engine.
Ibra wrote:
What is the difference? 91 in 91/96UL is Aviation Octane rating and UL = no lead?
UL91 and 91/96UL are manufactured according to different specifications. Other than that I don’t know.
The difference in engine list seems like typo? or is it an actual problem to run with?
No idea. I can only refer to the Lycoming info.
CS203 seems to add it on top of CS202 
Actually Hjelmco has 91/96UL which is not the same fuel as UL91
What is the difference? 91 in 91/96UL is Aviation Octane rating and UL = no lead?
The difference in engine list seems like typo? or is it an actual problem to run with?
Ibra wrote:
UL91 is EU-centric product (Total, Hjelmeco),
Actually Hjelmco has 91/96UL which is not the same fuel as UL91. Most engines than can use one can use the other, but there are counterexamples – interestingly both ways, e.g. a Lycoming O-480-A can use 91/96UL but not UL91, while a O-235-K can use UL91 but not 91/96UL
Seems the same specs as UL91: no TEL but more Octane? if an engine can run with 100LL (or 100UL) and 91UL, plus any mix of the these, it should work with 94UL
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.
Well spotted, I gather no one cares as usually any Avgas higher octane mix are usually allowed in engine and airframe TCDS? the CS-STAN is rather odd requiring some Avgas UL with octane = 91 rather than any Avgas UL with octane >91, it even specify manufacturers names in CS-CS203?
UL94 is US-centric product (Swift Fuels) while UL91 is EU-centric product (Total, Hjelmeco), it’s either dumb miss or smart market segmentation
Huv – your email address is bouncing back. You need to whitelist euroga.org with your email system. See the whitelisting threads
Does anyone know what UL94 is made of?
UL91 is supposedly 100LL minus the TEL.
