To PB or not to PB, that is the question: Whether ’tis nobler to endure the pings and knock of inadequate octane in our airplanes’ engines or to rise up and add lead to suppress them.
If you look at a periodic table, most elements are identified by the first letter of the name. But some are less obvious. For instance, PB is the symbol for lead. When they were laying out the periodic table, they thought that one of the major uses for lead was a carpenter’s plumb bob and so they decided to use PB.
Lead as a soft low melting temperature metal has many uses in batteries, shot gun shells, auto body filler, etc. It is also used as an additive in paint and gasoline. But lead can be a health hazard if it enters a person’s bloodstream. So why is it so widely used?
The main answer is that lead, in most forms, will not enter the bloodstream, so is safe to use — if done properly.
In the 1920s and 1930s, there was a lot of work on developing an anti-knock additive for fuel. Scientists found that many metal compounds, such as copper, iron, and lead, would increase the apparent octane of gasoline.
The interesting part is that no one really knows how the metals work. The best answer I have heard is that they quench the pre-flame reaction which, in turn, reduces the temperature and pressure in the end gasses.
But each of the metals had some very negative effects on engine life. Tetraethyl lead (TEL) was selected because scientists discovered that bromine and chlorine compounds would scavenge the lead through the burn process. The resulting compound could be expelled from the engine and the particles would fall to the ground.
With the need for higher octane fuel in military aircraft, TEL was adopted for almost all aircraft fuels and was a big advantage for Allied fighter aircraft in World War II. After the war, automotive manufacturers found they could increase performance in their cars with higher compression engines, so an octane race among fuel suppliers began.
The fuel refineries quickly found that adding TEL was the cheapest way to increase octane, so almost all mogas became leaded.
But in the late 1960s, there was a push to remove lead from mogas based on the theory that lead can be bad, so just get rid of it.
There were a lot of studies done to prove the health hazard of leaded gasoline, but none proved any thing conclusive. The one I remember was where blood samples from cab drivers in New York who worked in exhaust fumes all day was compared to blood samples from people living in areas of the world where there were no cars at all. There was no difference in lead levels between the two groups.
Some people do not let facts get in the way, so they continued to demand unleaded fuel, saying if you produce it, we will buy it.
In 1970, Shell introduced an unleaded grade of gasoline called Shell of the Future (SOF). It had an octane two to three numbers below regular leaded fuel, but cost a couple of cents more per gallon.
The inside joke in the oil industry was: Knock Knock. Who’s there? Shell of the Future.
As it turned out, all of the people who called for an unleaded fuel stayed away in droves. In many gas stations we had to pump the fuel out of the tanks because it was turning bad due to aging. After a year or two, SOF became GOP, gasoline of the past.
It was not until 1975 or 1976 when cars came equipped with catalytic exhaust converters that were poisoned by the lead in the exhaust. That led the federal government to mandate unleaded fuel, eventually outlawing leaded mogas.
In 2021, the only fuels with lead are avgas and racing fuels. In a recent report by the National Academies of Science, Engineering and Medicine, researchers used all of the correct buzz phrases, such as avgas is the biggest polluter of lead, can be inhaled, etc. But they still have no data to back up their suppositions. They just know that it sounds bad.
The media keeps saying we need to base decisions on science. But science is based on data, not what sounds good.
So, what should we do based on the facts and data that we have?
That answer is very simple: Nothing. Make no change at all.
If the fuel industry introduces an unleaded avgas, it will not satisfy all of the aircraft in the fleet. Plus, there is the very real problem of exhaust valve recession. Lead byproducts of combustion coat the exhaust valve and seat interface. This prevents the valve from grinding into the valve seat and recessing into the head. Without the lead, exhaust valves recess into the head until valve burning occurs.
Another issue: FBOs will need two grades of fuel if they are going to offer unleaded fuel, which will require two separate tanks. If they stay with just one fuel, they, in all probability, will stay with 100LL.
So, unless the government mandates unleaded fuel, not much will change. If the government does mandate unleaded fuel in aviation, it will probably shut down a large percent of the fleet. Kind of a Catch 22 isn’t it?
Unleaded gas will push Fadec to finally be adopted appears to be the implications.
https://www.aviationconsumer.com/industry-news/why-fadec-struggles-benefits-remain-elusive/
Can’t we all agree the best answer here is diesel? Ironic given that the big car manufacturers killed diesel despite it being better than unleaded or even hybrid.
What kind of pseudo-scientific garbage is this? Does this “publication” even have a chief editor? If so, is that individual aware of being employed here?
Permanently removed from my news feed.
Lead is incredibly dangerous as has been shown by numerous scientific studies. Please stop spreading misinformation.
I’m also a GA enthusiast and a pilot, but I would never argue that lead is harmless.
Best,
Robert
The Latin word for lead, plumbum, is the reason Pb is the symbol for lead, not plumb Bob. At the time the periodic table was made, virtually all academics spoke both Latin and Greek. This is why there are so many technical terms with roots in those languages. Even everyday words like “plumbing “ come from plumbum because once upon a time, many pipes were made of lead.
Secondly, lead is quite toxic. Pregnant women are advised against eating fish due to lead in the fish from environmental contamination. Numerous studies have shown developmental problems in children from environmental lead contamination. I believe that there are significant proven risks to the use of lead in fuels and even burning coal for power. This is not a manufactured theory: it is real.
I was right there with you until the liberal absurdity again coal. Clean burning coal is why your lights are on.
Lead is a known neural toxin it is sed the Roman Empire declined because of lead in the plumbing and drinking vessels which made the ruling class mentally deficient look at the behaviors of them it’s documented high amounts of pb are found in bone samples of them Years ago 13 ran a special on a disastrous artic expedition all perished because of poor decision they could have survived if they waited for the ice to melt but they loaded a life boat with bibles and nonessential gear and tryed to haul it to a impossible location it was determined that the lead sealed tin food cans were inodated with lead slag which contaminated the food reminants of these rusted cans were found showing lead which penetrated past the ends of the can in the sealing process lead was the duct tape of its day now we know it’s dangerous I have worked with lead and still do if used cautiously it’s ok but history shows it’s dangerous
Mr. Visser where do you get your information that lead, in most forms, will not enter the bloodstream, so is safe to use? That certainly is not the case when it comes to leaded avgas.
Are you not aware of the Duke University study showing children who live within 500 to 1000 meters of an airport that uses leaded avgas have higher blood levels of lead than other children?
https://scholars.duke.edu/display/pub827456
https://ehp.niehs.nih.gov/doi/10.1289/ehp.1003231
Are you not aware of the MIT study showing annual costs of IQ losses that can be attributed to aviation lead emissions.
https://news.mit.edu/2016/unfriendly-skies-piston-engine-aircraft-pose-significant-health-threat-0826
TEL was developed in the early 1920’s for use in gasoline by Thomas Midgley who then worked for General Motors. Their plant in NJ had to be closed due to 8 deaths and poisoning, Midgley himself had lead poisoning.
Ben you are sadly mistaken if you think TEL in gasoline has no health concerns. There are many, many studies which prove otherwise.
High atmospheric lead levels have been linked with serious long-term health problems from childhood, including neurological impairment.
Lead from fishing tackle and shot gun shells have led to injury to wildlife from the ingestion of the lead and slow erosion of the lead in water. I believe it is banned in most waterfowl hunting.
Sorry with this one article you have lost all credibility with me.
Thank you for a very well presented argument against unleaded fuel. I am amazed at how often people will accept unscientific data just because something sounds bad. We see this emotional reaction in every discussion of nuclear power plants and even in the discussion of reprocessing nuclear fuel. Now this country faces a huge stockpile of nuclear waste that could be utilized to create more electricity.
I believe you are incorrect about no need to worry about Pb in our environment. If you google American Academy of Pediatrics or EPA.gov, it is clearly stated that Pb exposure is a significant health threat, especially for kids. Your taxicab driver “normal blood levels” anecdote is misleading since most contamination with Pb is in the soil. Leaded products like paint as well as Automotive engines have clearly been shown to cause increased soil levels.
Why would you assume that breathing leaded gas fumes vs oral ingestion of Pb lead to the same health increased inconsequential consequences? Would anyone seriously want their kids ingesting/breathing in excess Pb?
Besides, except for high compression detonation prone engines, it sounds like there are alternatives to current low lead fuels. It also sounds like the aviation fuel industry and pilots don’t want to hassle with or pay for the conversion to alternative fuel logistics. I guess that is the moral part of this issue.
Thanks
Due to vapor lock issues I have used 100 LL in my 2011 LSA for at least 8 years. I have been careful to use a lead chelating agent (TEC) every time I fill up. Recently during my annual with only 550 hrs on the Rotax 912 ULS I had to have a top overhaul performed due to low compression and I was told that the valves were bad and that the rings were so corroded that they were very difficult to remove. What is your opinion on lead scavengers? Could I run mixture of AVGAS and LL to prevent vapor lock? I am told the TBO for this engine should be 2,000 hrs.
Exhaust valve and seat recession and the affects of TEL in any fuel have been duly noted and piston engines of all types have been able to utilize unleaded fuel with the simple concept of hardened seats and valves. However, less studied evidence, and more anecdotal than anything else, suggest that TEL is helpful in sealing the valve to seat interface given the nature of air-cooled engines to wear the inside diameter of exhaust valve guides in a manner that is not consistent or linear; certainly not like water-cooled engines or the highly-effective and tightly cowled Porsche power plants. Fact is, this wear is predictable and acceptable within specified limits for any Lycoming or Continental engine. But hardened seats and valves won’t change this wear rate, and certainly not for the better even if it did. Tetraethyl lead does seem to assist in generating a “cushion” of sorts to better seal the dynamic operation of a valve with somewhat less-than-optimum valve guide support, but as I said, it’s empirical and anecdotal, and generally not included in formal studies for an unleaded avgas replacement. It’s there and visible during a borescope exam, and its absence is cause for some concern to maintenance personnel.
Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is a reasonable alternative and has been employed in leaded and unleaded fuels worldwide. It has anti-knock qualities and still provides the “cushion” found with TEL, and it does so without the concern for lead bromide pollution. The extent to which Lycoming and Continental consider its use a “drop-in” replacement will be the driver for FAA acceptance.
I would like to have a short paragraph response to Ben’s discussion of unleaded fuel. I couldn’t do it, there is too much historical data that is relevant. Here is my response.
Ben Visser has a great deal of experience with engine oils however he either does not know of or does not understand the issues regarding leaded gasoline.
Let’s start with this: “lead, in most forms, will not enter the bloodstream”. Metallic lead is not easily absorbed, as Ben notes. Lead in paint readily enters the bloodstream. The lead used in fuel is tetraethyl lead, an organometallic. Tetraethyl lead is very readily absorbed and the lethal dose for an adult human is one gram. The ethyl groups penetrate cell membranes allowing the lead access to neurons, muscle and fatty tissue. You can get a gram either through absorbing through the skin or inhaling the fumes. The products of combustion of leaded gasoline have many lead compounds, a significant number of them are easily absorbed by plants and animals. Tetraethyl lead is absorbed by breathing the vapors. In 1924 five workers died of acute lead poisoning at a Standard Oil refinery in New Jersey. During the summer of 1924 15 workers in the industry died. These fatalities resulted in strict handling procedures for the material. This and other examples of the toxic effects of lead are documented in this EPA article from 1985. Lead accumulates, our bodies do not have a good way to eliminate lead.
https://archive.epa.gov/epa/aboutepa/lead-poisoning-historical-perspective.html
One of the problems with studying the health effects of lead is that the levels of lead in the blood that cause measurable effects are very low and difficult to measure. This recent article discusses the correlating between mental abilities as an adult and childhood blood levels. Blood levels as low as 5 micrograms per deciliter show statistical effects. A deciliter is a tenth of a liter, about 3 ounces.
https://www.reuters.com/article/us-health-children-lead-iq/childhood-lead-exposure-linked-to-lower-adult-iq-idUSKBN16Z26G
Ben says “There were a lot of studies done to prove the health hazard of leaded gasoline, but none proved anything conclusive”. How lead gets into humans is not completely understood. I agree that it is difficult to prove that blood lead came from gasoline. There may not be a study that clearly states how much of the lead in humans came from gasoline. Because much of the lead from gasoline became sub-micron aerosols it is very hard to track and can travel thousands of miles in the atmosphere. There are strong correlations. The following World Health Organization bulletin discusses correlations. In China about half the children in rural areas were lower than 10 micrograms/deciliter of blood while those living near industry and high traffic averaged from 22 to 68 micrograms/deciliter. While it is difficult to demonstrate a single path between an exhaust pipe and human blood the possible pathways are clear.
Much of the lead from engine exhaust is in really small particles, less than one micron. These particles can be inhaled, they get caught in raindrops, contaminate the soil and plants. Since leaded gasoline has been banned the amount of lead in the atmosphere has dropped 98%, an amazing feat. This means the lead available to inhale, contaminate soil and plants has dropped.
Tong, Shilu; von Schimding, Yasmine; Prapamontol, Tippawan (2000). “Environmental lead exposure: a public health problem of global dimensions”. Bulletin of the World Health Organization. 78 (9): 1068–77.
For some perspective humans from the West coast of the Americas and the Colorado river valley between 1000 and 1300 AD had bone lead levels of 0.01micrograms/deciliter, hundreds of times lower than the contemporary bone levels in present day populations living in remote locations of 0.8 to 3.2micrograms/deciliter. The lead aerosols from exhaust and other industrial processes can travel long distances.
“Measuring Lead Exposure in Infants, Children, and Other Sensitive Populations (1993)”. National Academies Press. Retrieved 3 February 2016
Ben is concerned about valve recession. Unfortunately he has presented no data in his columns. We all have data about valve recession in engines running on unleaded fuel. For the last 40 years we have all been driving cars that ran exclusively on unleaded fuel. The construction of the valves and seats of modern car engines are very similar to aircraft engines with aluminum heads and hardened valve inserts with hardened valves.
I have a 1961 Mercedes 220SE with aluminum heads and hollow stainless steel exhaust valves that are sodium filled. The valves are similar construction as the valves in my Continental 0-300 engine. I rebuilt the car when I got it without replacing valve seats and drove 80,000 miles before I had to do a valve job due to leaking seals. I had no valve issues with the engine and only lapped the valves during the valve job. I have a newer Honda with 200,000 miles on it. The only valve work was a clearance adjustment at 100,000 miles. I would be surprised if there are any readers who have had valve recession issues with their cars in the last ten years.
Ben’s last comment also has no data: “if the government does mandate unleaded fuel in aviation, it will probably shut down a large percent of the fleet.” I believe that well over half the general aviation fleet ran fine on 80 octane fuel and is eligible for existing unleaded fuel STCs like the one I have on my Cessna 172.
I have been using unleaded gas in my plane as often as possible since 1990, I have never had valve recession problems.
Totally agree w you. Thanks for your comments.
Thank you so much Angus. It is so important that correct information about the harm leaded avgas does is published!
Ben, like most of the rest of us (except you, it seems) can’t remember everything! He does the best he can, which is all anyone can reasonably expect!
Remembering is not expected. Good solid research when writing an article for an online news source like General Aviation News is expected.
If you call yourself an expert at anything….
How dare you backup your controversial affirmations with something like “The only study I can remember…”
Editors: How could you let this amount of unchecked personal opinion leak into your feed?
This guarantees I will never subscribe to this news feed and will do my best to dissuade any one to do so.
Goodbye Gael, try a chill pill. Holy hatrack
Gael thank you!
Because it contains ethanol, which is corn derived methyl alcohol, and since alcohol absorbs water, and since water can freeze, you don’t want to flying along and find your fuel pipes have clogged up with ice.
If you could find 92 octane with no ethanol in the fuel it would run in the Comanche non-turbo fleet just fine
Patric, I believe you are talking about mogas. Swift Fuels unleaded UL94 does not contain ethanol.
Hello, I’ve seen 94 octane unleaded gasoline back east at gas station pumps, why can’t that fuel be used in aircraft engines ??? It burns just fine in automobiles. It’s unleaded and has the octane to sustain performance, why not in aircraft ?? thank you.
Auto gas “octane” is not the same as aviation gas “octane.” Auto gas that is 94 “octane” is actually 94 AKI which is an average of the Motor octane and the Research octane of the gasoline and it says so right on the pump: (R+M)/2. The Motor octane of auto gas is lower than the Research octane of the gas and you will know neither value for any auto gasoline you buy. You will only know the average. Aviation octane is always MON octane; 100 LL is 100 MON octane at the lean setting. Auto gas that is 94 AKI may have a MON octane of 90 or even lower.
For the entire US population, during and after the TEL phaseout, the mean blood lead level dropped from 16 μg/dL in 1976 to only 3 μg/dL in 1991. That’s the data, not one cherry-picked study.
High lead blood levels lowered IQ, and increased violence.
I typically enjoy Ben Visser’s columns and often learn a lot from them. However I was very disappointed in this piece on unleaded avgas. The challenge of fully replacing 100LL with unleaded is huge and has so far not been solved, despite extensive research by both government and the private sector. However, he dismisses the recent NAS report as merely buzz-words with no data. No data? Perhaps he didn’t read it: one whole chapter (3) has 27 pages devoted to health effects of lead, and includes 5 pages of references to reputable studies specifically on that topic.
Ben would do well to remember the engineer’s motto: “In God we trust: all others bring data”.
After reading this, I’m blocking General Aviation News from my feed.
Origin of name : from the Anglo-Saxon word “lead; Latin, plumbum” (the origin of the symbol Pb is the Latin word “plumbum” meaning “liquid silver”.
The lead is poison to my engine. I’m hardly unusual.
But, my engine is also small, so nobody cares.
Amoco, then still part of the Standard Oil tribe, was peddling an unleaded premium(High Test, in the parlance of the time) mogas back in the 60’s. I used it on occasion in my sports car and motorcycle, both of which had high compression engines. In the NYC area, it was the only unleaded available from any refiner until the seventies. I was busy hauling said fuel from just after the 70’s fuel crisis. About then Amoco, by dint of government mandate, came out with their ‘blue’ mid-octane unleaded grade. From then on only their ‘red’ regular gas contained lead for a few more years until everyone went completely unleaded. There were issues for some but the sky never fell. Today’s cars deliver unprecedented dependability, come with economical and yet powerful engines that can run to 200k miles if cared for properly. At the bottom rungs, GA is still propelling itself with essentially 30’s technology. BTW, valve rotation is already SOP in most if not all aviation recips, at least the opposed layouts anyway.
This article was laying it on pretty thick with petty prosaic political potshots. It aligns itself with the knuckle-dragging libertarian ignoramuses who keep their wallet on a chain, drive a beat up 70’s Firebird/Camaro with all the emissions equipment removed. We really need to snap out of all these romanticized notions of ourselves. Mrs. Cleaver didn’t really stand over a stove, wash dishes and vacuum a meticulously clean house in the same perfectly ironed dress, while wearing heels with matching pearl earrings and necklace.
Lead, petrochemicals, ultraviolet radiation, EMF/RMF, soot from airliners, soot from ground up tire and asphalt dust, soot from diesels, just a cursory list of things that are very, very bad for you. Now if you really want to find these pollutants and the people most affected by them you need to find people with the appropriate given names. Inner city names like Juan,Maria and/or Tyrone,Taisha not country club types like Donald and Melania or the Koch bros.
Don’t be picking on Ben. He generally does a decent job as a contributor to this post. Everyone who writes a column might not meet your exacting expectations, but everyone else’s view might not be the same as yours. That’s life in the big city, pal!
It is because of poorly-researched articles by people like Ben Visser that reveals GAN is not a source for competent aviation writing. Ben has clearly demonstrated that he has not read any actual science, or perhaps does not understand how science works. My guess is Ben simply misses his former job as a DDT crop sprayer, since the science on THAT one must also be an open question for him. Poor Ben.
Exactly. Some of what he says may have been true in the 1960s, but all his knowledge seems to be 50 years out of date. As someone else commented, it reads like the tobacco industry trying to promote cigarettes as a health product. Leaded fuel is dangerous to health – this has been proven beyond all doubt time and time again. Large numbers of aero engines are approved to run existing unleaded Avgas grades, and have done so for decades with nothing but improved engine life as a result (see Lycoming service instruction 1070). GA now accounts for the majority of lead pollution, and we need to clean up. Visser is like a broken record – he has been promoting this head-in-the-sand nonsense for years and does nothing but harm GA in the process.
Plumb Bob? LOL. Pb comes from the Latin “plumbum”.
Like many elements, the symbol comes from its Latin name: plumbum
https://en.m.wikipedia.org/wiki/Lead
Ben isn’t completely off the mark, he just has it the wrong way around. The Plumb Bob got its name from the Latin name plumbum so there is a relationship to the Plumb Bob, just not correctly stated.
https://en.wikipedia.org/wiki/Plumb_bob
I overhauled many aircraft piston engine’s when I worked for an aircraft engine rebuilder, of all the engines we overhauled I never saw one with receding valve seats because of leaded fuel being burned through them…..In fact the thought never entered our minds. This is a fact !!
PB,
I think most of those kids from that study grew up and became politicians!
I’ve commented on this subject before. For a country to spend untold funds and resources to revise a fuel that comprises one half of one percent of all fuels used in the USA is utterly ridiculous! Aircraft engines were designed to use leaded fuel, and due to limited production, no manufacturer will be redesigning piston engines anytime soon!
Leave AvGas alone! It was bad enough when 80/87 was phased out!
Henry, I was interested in the Santa Monica Airport hysteria, and I found exactly that – hysteria.
The “Lead belching over the community” was the common thread, and is repeated now at Reid-Hillview.
At SMO there was an emissions test with monitors placed around the airport. The naysayers relied on a monitor off the east side of the perimeter road and ignored the monitor between the road and the airport (which had negligible emissions).
The lies prevailed, and then the FAA Secretary agreed to the closure. I was stunned that a government facility that is charged with fostering General Aviation would approve closing the first airport in California.
Now, Reid-Hillview is following the same path, and the Hispanic community is excited to close the airport because they think that it will be replaced by “affordable housing”, not realizing that they already live in the least costly housing area in the Bay Area, thinking, I guess, that they will get “free” housing. They use the lead argument as leverage.
The lead argument is just that – an argument. We can cry all we want, but the argument is persuasive to the politicians whom we elect but then don’t support GA. The mentality seems to be that we should all fly with airlines, all as ‘common man’ travels, as if we are the spoiled brats that don’t deserve a local airport. It’s sad.
Elect representatives who will support GA. That’s the only answer.
My recollection was that a 1973/4 study of children in an apartment building at the west side of the confluence of the 405 and 10 freeways in West Los Angeles, affected by the prevailing winds from the west that would blow exhaust fumes toward the building, showed higher levels of lead in the kids. Supposedly, lead causes mental retardation, slow learning etc. as stated back then.
I wonder where those kids, now adults, are today and if they turned out ok?
J.D. has a link to an article in Scientific American magazine, which is usually a pretty reliable source. It says that 70% of the GA fleet will run fine on unleaded gas, but mentions valve seat recession problems. This can be fixed by the usual aviation expedient of throwing money at it. Hardened valve seats plus valve rotators usually does it, and these can be installed (if available) when the cylinder is overhauled.
Where the article goes “somewhat” astray is where it says the remaining 30% of non-compatible aircraft will result in a potentially profitable market for alternative engines, so those airplanes will be OK as well.
That, my friends, just ain’t gonna happen. Nobody, and I mean nobody is going to design and certify a complex new engine to retrofit into a fleet of only a few thousand piston twins, many of which are nearing the end of their useful life anyway. Those engines are going to be EXPENSIVE (if they happen at all, which is doubtful), and who will buy two of them and install them (which also won’t be cheap) into a high-time, high-maintenance, low value airframe?
In the absence of 100LL, a lot of airplane owners are going to be schlepping gas cans from the local marina (non-ethanol gas) or non-ethanol gas station pump (where available) , and the high rollers amongst us will be buying Jet-A. The 421C crowd is going to have a problem . . .
How much data is there to support valve recession with unleaded avgas? I’ve read reports that certain unleaded fuels have not shown that to be the case with extensive testing in both test cells and flight testing. Can anyone show data that unleaded avgas causes valve recession with all unleaded avgas?
Its interesting to note that responses fall along what I would bet could be probable political lines.
That being said, I comment: “If the government does mandate unleaded fuel in aviation, it will probably shut down a large percent of the fleet. ”
And why would that not be the object? You non-governmental types taking up airspace (and breathing my air). Only gov, military, airlines, and one-percenters should be allowed to fly around.
Yeah all the peons to the back of the electric bus 🚎
Pb comes from french “Plomb” not from the “fil à plomb” of the american carpenter !!!
Actually, it comes from the Latin word for lead….plumbium. In Roman times, water was carried by lead pipes, and were installed by…plumbers. It’s the same reasoning the periodic table uses Ag for silver (Latin word for silver: Argentum). Au is gold (Aurum). Fe is iron (Ferrum). Etc, etc, etc (which is also Latin for “et cetera”, which translates as “and so forth”).
The only good language is a dead language!
Ben- With all due respect, and perhaps you were joking, but the “Pb” used on the periodic table comes from the Latin word for lead: “plumbum”. Lead was once used for plumb bobs, hence the name.
Yes, things get done in this country due to hysteria and political pressure. Who would really think it’s a good idea to put our food and water in our car gas tanks (everything has corn or corn syrup in it now) if they actually paid attention? Not to mention the lower mileage and corrosive effects ethanol has. And especially since we are fossil fuel independent. It’s simply a payoff to big agri-business. Sadly, aviation fuel will finally suffer a similar sort of fate as soon as the right group makes enough noise about it.
Thanks for your excellent articles!
This article uses a picture of a pilot sumping leaded fuel with gloves (because it is a health risk) to argue that there is no conclusive proof that it is a health risk and that no changes in fuel use should be made. The lack of factual support is on the claim that there are no adverse health effects from leaded gas.
https://www.epa.gov/lead-air-pollution
https://www.scientificamerican.com/article/lead-in-aviation-fuel/
https://www.who.int/news-room/fact-sheets/detail/lead-poisoning-and-health
http://www.4cleanair.org/sites/default/files/DukehealthStudyavgas071311_0.pdf
He is also wearing a coat, suggesting it is cold outside. The glove are worn for the same reason.
Benzine is a carcinogen with or without lead.
My guess is that 100LL will be available for at least 15-20 years.
[ that’s my hope. After that I most likely won’t be flying anymore.]
The risky issue with TEL is that there is only one company in the world that makes it; Innospec, and they are in England. If they are forced to stop producing it by their Gov’t,…. no more 100LL, and we park all our GA aircraft, or risk using auto gas with ethanol.
I’ve suggested in other articles to go back to MTBE, an ester, and require above ground tanks. The problem that caused MTBE to be banned was leaking underground tanks and that MTBE is soluble in water and polluted ground water…
Most of the low compression [7:1 ] engines can run on 86 octane gas, but cannot contain any alcohol.
The higher compression engines, [ 9:1 or more], and turbo-boosted engine need the 100/130 octane fuel.
Oh, and BTW, Pb was used as the symbol for lead, since it was named Plumbum a Latin word.
Recently retired and want to fly around the country to fulfill a lifelong dream. I waited on the engine overhaul hopeful that the lead problem would be fixed. I have decided that if I wait any longer, I will be in a nursing home with a drool cup. The engine will get the higher compression STC to compensate for the constant lead problems…
Gonna enjoy that trip.
Your defense of lead and TEL reminds me of the tobacco industry’s history of denial. The science is not controversial: lead is bad and TEL is really bad (about 1% of it passes through engines intact). The evidence you claim to be lacking is out there (though often in academic papers behind paywalls). An example, though I’m sure you will find a reason to ignore it. https://arefiles.ucdavis.edu/uploads/filer_public/d6/2d/d62d46a3-8558-48a7-bbdc-1c9183b47482/hollingsworth_rudik.pdf
It compares, in a relatively controlled way, the effect of lead removal from NASCAR racing fuels, before and after. Short answer: measured blood levels of lead in the blood fell afterwards. And the effects were measurable out to 2-3 miles away from the track.
Regardless of the effect on aviation or your opinion on the matter, TEL is going away, sooner or later.