Unleaded Fuel

citrusflight · July 5

I fly 76 Lance with IO-540

From my little research I am in anxiety mode. One law to ban 100LL. No solutions.

Three fuel types wont cut it. FBOs will pick one type and from what I read you cant mix them so when on a cross country you may be stuck. Lycoming SI 1070AB does not cover IO-540-K. Are there any effort to delay this (2030) or consolidate one fuel type for GA pistons? Is Piper Owner lobbing for GA?

Thanks all Happy 4th weekend.

RJM

griff390 · July 5

https://piperowner.org/talk/discussion/157714/unleaded-fuel

Hi RJM;

According to the FAA's EAGLE unleaded fuel program, all leaded and unleaded fuels may be mixed in any ratio or proportion.

That being said, it's up to the owner/operator to ensure that the fuels meet the requirements of the AFM (Aircraft Flight Manual) for that particular plane.

https://www.faa.gov/unleaded

The FAA, along with private companies are developing drop in replacement fuel(s) that must also meet market demand quantities (currently ~400 million gal/yr), have distribution channels that can supply all areas of the country, and is compatible with all engines including turbo, high performance and vintage.

Tom_Jax · July 6

I haven't heard of any attempts to further delay the sundowning of 100LL. This is due in large part, I suspect, to the only approved manufacturer of TEL, Innospec, publicly announcing they will stop production in late '28-early '29. They have a critical component that will be due for replacement that won't be worth investing in with the legal requirement in place to stop using it.

GAMI is furthest along, and if they were more open to discussing the paint/seals issues, rather than finger pointing, and had gone through PAFI/EAGLE, I believe all the anxiety pilots are feeling would go away.

citrusflight · July 6

Jim and Tom thanks for your feed back

cherokee383 · July 10

I'll have to look at my notes, but when I went to Lycoming tech school, I remember them saying something about all of their engines are good with high octane no ethanol auto gas. I'll dig for my notes and get back with you.

Tom_Jax · July 10

Kyle, I'd love that info, too. I have an IO-360-CIC6 in my Arrow, and am not on the STC AML for any of the auto fuel options.

cherokee383 · July 22

DATE: If this link doesn't work, message me for the service bulletin. SI1070AB

empannin · August 2

I think the best solution out there might be moving to UL94 (100LL without the lead) and implementing water/methanol injection for 80% to 100% power for the engines that really need it.

You would need a tank, high pressure pump, spray bar and controller but this technique cools the air, provides an octane boost from 94 to ~ 116 and would also clean out the combustion chamber, intake, and exhaust system. The fluid is essentially windshield washer cleaner but even specialized mixes are about $10 a gallon and for use during take off in my PA34-220T I would be using about 4 gallons an hour for 60 seconds = 1 cup per engine and 60 takeoffs for a 5 gallon system (per engine). About 60 cents per take off (per engine). I could live with that.

It working would be obvious with a intake air temp gauge. It drops the temp by 100 degrees. This would not be for more HP - just detonation margin so the numbers might actually be even more favorable for consumption.

The government could subsidize the conversion cost. There was a company making then for about $12k per engine and street kits are around $700.

This would be way less expensive than all the alternatives. Gami is expensive and the Xylene in it can strip paint. Swift 100 has issues as I understand it too but I don't recall what they are.

In the proposal above nothing changes in the supply chain for fuel distribution. You can use the same tanks, hardware, procedures, etc and the fuel is exact same except no lead.

Most planes will not need any modification. For the higher HP planes (also some of the biggest consumers) they would need modification.

You could also mandate advanced engine monitoring and even if the tank ran dry you could potentially run off a reduced power table such as cruise climb which is a rich 75% in my plane.

Even with the potential cost to me I see an overall upside to aviation and the cleaner burning fuel + cleaning capabilities of water/methanol might lead to higher TBO's. Many engines get tagged out for excessive oil consumption/low compression from stuck rings.

griff390 · August 7

Here's the latest. According to the FAA, a "drop in" unleaded 100 octane fuel is "not feasible". Most of us would agree that placarding is not a big deal.

It's a good read.

https://www.aopa.org/news-and-media/all-news/2026/august/06/faa-refines-unleaded-fuel-transition-framework?utm_source=ebrief&utm_medium=email

Unleaded Fuel

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