FAA Q&A Lays Down The Law On Banning 100LL

It’s actually 160 hp, for the Rotax 916 iS. They have a six-cylinder under development which will probably exceed 200 hp. The point is, all new manufacturers of aircraft engines design them to run on mogas or Jet-A (diesel). We should be looking forwards, not backwards.

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Thanks to Darren for his statement. I also appreciate his reference to Rotax engines. Many of us fly aircraft with those engines, yet it’s the first time I recall seeing any mention of them in all the AvWeb discourse on unleaded fuels. Like many Rotax owners, to take care of my engine I have to carry auto gas in gas cans to fuel my airplane. I would have loved to have seen access to unleaded fuel (either auto gas or 94UL) required in grant assurances by last year’s Reauthorization legislation. But there seems to be almost no thought being given to the continued costs imposed on aircraft owners by forcing them to use a fuel that they do not need and that is harmful to the life of their engines.

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Where did the 70% statistic come from?

Please get your facts straight.

Transponders and ADSB are not required items. And if you think they are you might want to start looking out the window more because there are a lot of aircraft that are not equipped with those items.

Yes we fly inside the mode C veil around class B airspace.

Yes we fly into class C airspace

Yes we fly in Class D airspace

But you are correct you will most likely find us in class E and G

I own several aircraft. I have done much testing using leaded, unleaded and a mixture of both fuels. And yes the lead in fuel keeps the older air cooled normally aspirated aircraft engines running better, longer, safer and with less ware between overhauls.

Thanks Mike

"While airplanes with lower compression engines make up 70 percent of the GA piston fleet, they only burn about 30 percent of the 100LL. Higher compression engines use 70 percent of the 100LL supply. "

IOW the high compression engines are burning most the fuel and doing most the traveling. Time to stop talking about “Rotax” and this or that bug smasher. People like me who typically fly 500-700nm missions for business are the real users. When you think about it, it makes sense.

So where did AOPA come up with this? Yes Twins burn almost twice as much as single engine aircraft. But piston twins are a dwindling market and can be replaced with Jet A burning substitutes. Larger piston singles have to make up the difference. Take out Cirruses used in primary training and then what do you have? Probably an amount close to or less than the so-called “bug smashers”.

I knew you would question the number because it does not comport to your narrative, and that is all you got, a narrative.

Another way of looking at that statistic that never gets talked about is 70% of aircraft operators have been paying higher fuel and engine maintenance costs for 40 years to support the flying done by the other 30 percent. I think it’s more fair to say that each aircraft flying segment has been carrying the other’s mail.

This isn’t that different from the sun setting of 80 octane. That required new engines on the Cessna 150 ( to become the Lycoming powered 152) and the 172 ( the much maligned N-model). If 100LL goes away, Beech, and Cirrus will adapt ( if they think there’s still money in GA) and buyers can choose that solution or they can take their turn in the same barrel the “bug smashers” were in for 40 years.

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Operators like Cape Air, who still flies Cessna 402’s because there is nothing currently available to replace it, probably burn more 100LL in one day than most weekend flyers burn in a month. When my home airport had to replace both 80 and 100LL octane tanks due to EPA mandates in 1989, the owner had to make a choice. He couldn’t afford to spend over $100,000.00 each for two new tanks, so since the oil companies were in the process of dropping 80 octane the choice of fuel to sell was made. I just purchased an older plane which has an engine the was designed to burn 80 octane fuel, not the 100LL that is sold now. I purchased an auto fuel STC since in my home area there are several gas stations that sell ethanol free auto gas that is 90 octane. I’m sure most small airports that have just one fuel storage tank that is used for 100LL are going to continue to sell 100 unleaded once it is available. The volumes in avgas sales just cannot justify the cost of a second dispensing system just for a lower grade of avgas.

I do feel that the FAA should stop any further certifications or approvals for engines that require 100LL. Same with airframe type certifications. Have to start somewhere. If the FAA keeps approving airplanes that run on 100LL then the longer it will take for the unleaded option to be available.

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I get the gist of your comments, Matt.

Just for accuracy and to clear up any confusion, Cape Air does also operate some other aircraft (which probably also require 100LL with, I think GTO-520 Lycoming variants) such as Tecnam P2012, for example.

100 LL has approximately 2x the lead of leaded auto gas.
Lead is a continuing serious environmental and human poison.Nascar banned it after elevated lead level in team member blood was found within the racing community. I worked in a gas station as a kid in the 1970s and the occasional kick back of leaded gas which was still for sale , caused significant health issues in my hands for years to follow. the use of lead in fuel has shown to have lead to many societal problems for a very long period of time. for reference pleas read the attached AND it you question the summary of the document refer to the PEER REVIEWed scientific papers referenced in the foot notes..Tetraethyllead - Wikipedia

While scientific data and information on the effects of lead is plentiful, we are dealing with an industry, which has categorically rejected the idea of progress in terms of aviation piston engines for nearly 8 decades. Just picture an (any, really!) engine requiring an engine oil change every 25 to 50 hours in todays day and age. This is INSANE!

I remember working in the automotive industry in the US in the early 2004-2005 time and vividly recall that I was in shock, when learning that Americans were told to change their oil and filter every 3000-5000 miles. Like clockwork, we changed hundreds of gallons of motoroil per week, despite the fact that modern automotive engines run 20-30.000 miles with the same spec oil in Europe.

AVGAS is finished from every viewpoint. Its future use is incomprehensible from every angle.

Users want a drop-in replacement, preferrably equally priced or (better yet) cheaper. 25h and 50h oil changes no longer cost $10 nor can we excuse changing expensive oil filters every few weeks. Things are getting expensive and with our current path and quality of leadership, that trend will continue.

The time for round-table meetings and a targeted campaign between stake-holders, users, distributors and developers, engine and aircraft manufacturers was 30 years ago.

From history we know that humans are their own worst enemy when money, power, prestige or greed are involved. We know that entire empires have sunk this way. Yet, we are able to think about occupying Mars and we send rockets into orbit on tourism missions, but we cannot, for the life of us, get this issue solved.

Maybe 10 generations from now people will dig up old Cessna’s and Cirruses and discover which type of advanced electronic devices are screwed into the panel, but then ask: “What where they thinking?!” when the old firebreathing Lycoming or Conti Engine is dug out…

agreed . the reason for the use of the engines was to NOT have a PSRU or liquid cooling. these were maintenance headaches in WW2 aircraft BUT the saving grace there was the extremely short life of fighter aircraft engines. Ross gaurentedd 100 hrs for the merlin this increased to 200 hrs. the big radius ran far longer. This drove th adoption of big slow air-cooled aircraft engines. HOWever ROtax has show unevivicolly that a PSRU with high revving engine can very effectively replace the Lycoming Continental standard. HOWEVER knew they cost more. they also wear very little with the TBO driven by the multi piece crank design. (though a zero time crank and rod assy is MUCH MUCH less expensive that a similar Lycon.

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