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Finding that lead emissions from aircraft engines contribute to air pollution

450 points by Metacelsus 3y ago

coding123 3y ago
thumbs up.
JanSolo 3y ago
Didn't they just legalize unleaded avgas very recently? After a multi-decade regulatory review process? Seems odd that they were so hesitant to legalize it and now that they did, it becomes the only option!
- Kapura 3y ago
  The only odd part is that it took so long. Leaded gasoline has been known to be toxic for many, many decades.
- crazygringo 3y ago
  Or it makes perfect sense. Once it's legal, what reason is there to keep the poisonous one around? It's not odd, it's exactly what you'd expect. The only odd thing is that it took this long.
  - TinyRick 3y ago
    > Once it's legal, what reason is there to keep the poisonous one around? Many (older) aircraft engines need leaded fuel.
    - kevan 3y ago
      I remember news saying the FAA added supplemental type certs allowing G100UL for basically every engine in 2022. What gaps are there?
      - sokoloff 3y ago
        Distribution. https://www.g100ul.com/faq.html#availability https://www.g100ul.com/faq.html#availability
    - mlyle 3y ago
      As far as we know, G100UL works in anything.
      - labcomputer 3y ago
        Yes, but it's not currently legal to use in anything. You still have to apply for and buy an STC for your specific airframe's serial number and engine's serial number. Then you have to add some paperwork to the logbook and POH and add placards to the fuel fillers and cockpit. In theory you should be able to automatically get it for anything which was approved from the factory to use 100LL, but the STC application form (here: https://stc.g100ul.com/aircraft/ https://stc.g100ul.com/aircraft/) does not allow you to select most mid-century large radials (which were usually originally certified on 130) or the airplanes they were installed on. To be clear, this is a great thing, but you can't legally just fill G100UL in any random airplane.
        briandear 3y ago
        Exactly. Remove the STC requirement. If the fuel is unreliable that it won’t work in every 100LL aircraft, then it shouldn’t be forced upon us. If it is completely safe, then an STC should be unnecessary.
        mlyle 3y ago
        What about something in-between? The fuel is reliable in almost every design, but there's some design out there that -relies- upon lead depositing to engine surfaces to be reliable (as opposed to the octane effect). I don't think it needs to work in every conceivable 100LL aircraft: just almost all. Every is a high bar.
        lazide 3y ago
        Which is why it is taking so long. Because if an engine grenades on takeoff, it's almost guaranteed to kill someone. If that was because of the fuel switch, that's a real problem.
        3y ago
    - tastyfreeze 3y ago
      Can't upvote this enough. This is going to kill small operators that might not be able to comply. Why not just let the leaded fuel users die from attrition naturally?
      - aaomidi 3y ago
        Because lead is not safe? Like small planes are spewing lead over everywhere they’re flying. I’m glad this is happening. I don’t really care about small operators vs the health of everyone else, and especially kids in the case of lead.
      - munk-a 3y ago
        Considering we're talking about leaded fuel that is some terrible wording.
        aaomidi 3y ago
        I know right? Operating a plane is a privilege, not a right.
        lazide 3y ago
        So, apparently, is operating a motor vehicle. Except large swathes of the economy will collapse without them. Oh, we aren't talking about tire dust? Never mind.
        eesmith 3y ago
        Then let's talk about it. Unlike lead, we've only recently had the technology to measure and quantify tire wear pollution. For example, we didn't realize until 2020 that 6PPD - already toxic to many aquatic organisms - can oxidize become 6PPD-quinone, which is acutely toxic to coho salmon and some other fish species. This solved a 20 year old mystery of so many coho salmon died after a rain storm. That's why the California Environmental Protection Agency has passed a rule requiring tire makers to declare an alternative by 2024. https://dtsc.ca.gov/scp/motor_vehicle_tires_containing_6ppd/ https://dtsc.ca.gov/scp/motor_vehicle_tires_containing_6ppd/ That's in addition to the particulate pollution from tire wear. ("Research from Emissions Analytics shows that particulate mass emissions from tire wear is thousands of times greater than those from tailpipes, which have been vastly reduced in recent years by high-efficiency exhaust filters." - https://edition.cnn.com/2022/08/16/world/tyre-collective-microplastic-rubber-waste-climate-hnk-spc-intl/index.html https://edition.cnn.com/2022/08/16/world/tyre-collective-mic... ). We of course need to regulate them better because electric cars are heavier, so tire particulate pollution is expected to increase over the next few years. There's also brake pad pollution, like the EPA's Copper-Free Brake Initiative to remove copper, "mercury, lead, cadmium, asbestiform fibers, and chromium-six salts in motor vehicle brake pads." https://www.epa.gov/npdes/copper-free-brake-initiative https://www.epa.gov/npdes/copper-free-brake-initiative . That's a voluntary program, but California and Washington have mandatory requirements. I trust that you support these efforts to reduce car pollution, and are not simply using the lack of discussion about them in this thread in order to score internet points for implied hypocrisy? Both tires and brakes have the advantage that they are replaced every few years/decade, so regulations can target manufacturers. An aircraft engine can have decades of life, so any costs of switching away from leaded fuel are felt directly by the owner.
    - dontlaugh 3y ago
      Any petrol engine can run on 100 RON fuel. There are several options that involve no lead, generally substituting with ethanol.
      - labcomputer 3y ago
        Sure, and any petrol engine can run on 78 RON fuel to. It's just that if you try to run it at full power you'll blow it up. Wee bit of a problem on takeoff. Same thing with running certain large piston airplane engines on 100. They blow up. > There are several options that involve no lead, generally substituting with ethanol Ethanol is corrosive to aluminum. Thankfully airplane designers have never used aluminum in airplanes...
      - mchid 3y ago
        We can't use ethanol because of phase separation amongst other reasons but this is true considering we've been using stuff like toluene probably even longer than tel.
    - kube-system 3y ago
      They don't "need" lead any more than pre-70s cars "need" lead. They were designed to run on leaded fuel, but there are lead replacement additives which are able to fulfill the same technical requirements. TEL is just cheap, effective, and well understood for legacy applications. It isn't the only option to boost octane, by far.
      - roflchoppa 3y ago
        The only issue I had on my 240z was the valve seats were some super soft brass like material, those needed to be swapped as they were beat to up and did not seal. The 75+ heads, all have steel seats. I’ve actually never experienced the, “California gas sucks” issue that car people from the mid-west talk about, have never had an issue with it. ¯\_(ツ)_/¯
        mcronce 3y ago
        Maybe my understanding is incomplete, but AFAIK the "California gas sucks" thing is just because the highest grade you can find at most pumps there is 91, while we get 93 in a lot of other states Not that it matters when everything made for "premium" is tuned for 91 from the factory anyway, not 93
        arcticbull 3y ago
        California actually has different gas that produces fewer emissions - it's part of the reason gas is more expensive here. It's called CARBOB grade, c.f. RBOB/CBOB.
        dicknuckle 3y ago
        Today I learned, thanks!
        mcronce 3y ago
        TIL, thanks for the info
        3y ago
    - lfuller 3y ago
      G100UL, the current unleaded alternative to 100LL, has been tested to act as a drop-in replacement for any and all aircraft engines that run on 100LL. If you can run, 100LL, you can run G100UL. The main issue is with mogas (standard car gas) - many aviation engines can't run it.
      - jacquesm 3y ago
        Is that due to the Ethanol fraction or some other factor?
        i386 3y ago
        From memory octane levels have a huge bearing on engine performance and that affects take off distance. Aviation has had a much higher octane rating than your typical car gas.
        ctennis1 3y ago
        A myriad of things: Octane, ethanol, and also additives used in the winter vs the summer.
        labcomputer 3y ago
        That's part of it. Ethanol is incompatible with materials commonly found in airplane fuel systems. Another aspect is that many piston airplane engines need high octane because they have relatively high compression ratios: WWII era engines need 130 octane to develop full horsepower (they can be operated at reduced manifold pressure on currently available 100 low-lead gas), and even many post-war civilian engines require 100 octane. Still another aspect is that the FAA is relatively conservative and doesn't want to approve something that might lead to, for example, vapor lock or fuel freezing issues.
        mrguyorama 3y ago
        >airplane engines need high octane because they have relatively high compression ratios: WWII era engines need 130 octane to develop full horsepower I mean, high octane and compression relative to other 1960s engines. The common engines in nearly any single prop cessna have about a 9:1 compression ratio, which was massive back when it was built, but laughably bad compared to anything manufactured after the advent of Fuel injection and better piston geometry. Modern cars regularly have over 12-1 compression ratios on 87 octane. 1960s era carbs and top ends were just abysmal and did a terrible job of mixing the fuel and air charge and controlling the flame front, because we just didn't have the kinds of computer controls and fluid dynamic simulations we have now, to dynamically prevent knock. Rotax engines are modern and can reach identical performance figures or better, with the same weight or lighter, simply by using modern techniques like fuel injection or a small turbocharger. They do this while running on 91 octane
    - heelix 3y ago
      The beauty of G100UL is you just need an STC - just paperwork - to be legal with GA aircraft. All gasoline powered aircraft and engines in the FAA’s type certificate database are covered by the STC for G100UL... which is amazing. I'll be doing it, as soon as our home base carries it for my 56 o200.
    - mchid 3y ago
      They literally don't when G100UL exist, which is approved as a full drop in replacement safe for all engines.
- foxyv 3y ago
  Mostly because the use of lead in fuels is something to avoid at all costs. I know a lot of GA people were VERY happy to hear that they approved G100UL. Leaded fuels aren't just toxic, but they also cause issues with airplanes such as lead fouling. AVWeb did a couple videos on the subject here: https://youtu.be/9F-WngVMJBQ?si=Qb_IYu4QwZlOTDCv https://youtu.be/9F-WngVMJBQ?si=Qb_IYu4QwZlOTDCv https://youtu.be/ovJBJjZTjsk?si=f2OwwZMmuEUTx6wL https://youtu.be/ovJBJjZTjsk?si=f2OwwZMmuEUTx6wL
- codexb 3y ago
  The problem is that they won't approve engines for general aviation that use unleaded gas. All the engines used in general aviation are basically 60 year old designs. General aviation is not a major concern for the FAA. It's an afterthought. And so they don't devote any time to approving new, modern engines and make it as difficult as possible.
  - phkahler 3y ago
    >> The problem is that they won't approve engines for general aviation that use unleaded gas. Except that they did approve a lead-free fuel for use in all those engines last year. Banning leaded fuel is the obvious next step.
  - jabl 3y ago
    Many, or even most, of the engines are indeed old designs. But e.g. Rotax offers certified version of some of its 900 series engines, which are a relatively new design, some with fuel injection, FADEC, etc.
- phkahler 3y ago
  >> Didn't they just legalize unleaded avgas very recently? More specifically, I believe they certified that a particular fuel as suitable for use in ALL engines that previously relied on leaded fuel. Until that happened there was a somewhat legit concern about banning leaded fuel. What people are afraid of now is a monopoly on the new fuel leading to higher prices. But there's already a near monopoly on leaded avgas. It would be really cool if someone developed a new aircraft engine suitable for replacing all the old models and able to run on a wide range of fuels (this may actually exist). But even then its a slog to get that engine certified for all the planes you'd want to use it on.
  - marcosdumay 3y ago
    > It would be really cool if someone developed a new aircraft engine suitable for replacing all the old models and able to run on a wide range of fuels As a recent article here talked about, nobody is making new aircraft for general aviation. Or at least, nobody is making anything innovative for it. But there exist plenty of engines that are good enough for planes and can run on a wide range of fuels. They are just not getting into GA planes.
    - SoftTalker 3y ago
      There is some interesting stuff happening in battery-electric aircraft as trainiers. You can only fly them about 45 minutes and within a local radius of the airport but they are good for people learning the stick-and-rudder basics of flying.
      - MrDrMcCoy 3y ago
        Gliders are even better for learning flight basics, do a better job of teaching you to anticipate and work with turbulence, and have a variable time limit.
        lazide 3y ago
        Glider hours aren't going to count towards any useful type certification though? Unless you think someone is going to be qualified on a Twin Otter because of 1000 glider hours?
- SomeHacker44 3y ago
  Availability of the new unleaded fuel is extremely limited. It is also very expensive. I also believe there may be a fee involved per airplane to use it (one time for an STC). The fee I heard is nominal $250. I have never flown to an airport with it yet. i have probably landed in over a dozen different airports in the last few months with a leaded gas engined plane.
  - outworlder 3y ago
    > I also believe there may be a fee involved per airplane to use it (one time for an STC). The fee I heard is nominal $250. What is $250 in aviation terms? It's nothing. Availability of fuel is a concern, sure. But a fire has to be lit on people's ass, otherwise they will not move.
  - scarby2 3y ago
    the requirement for the STC on a per-aircraft basis is now gone AFAIK. That was the effect of the FAA's "legalization" last year.
    - sokoloff 3y ago
      You still have to purchase the STC for your airplane serial number and engine(s) serial number. What the FAA did was approve that all-model STC as being valid/legal to sell and "install" (which is just placards).
- TylerE 3y ago
  The problem is, "legalizing" it is like 0.1% of the work. The hard part is all the testing/certification you have to do for every single aircraft and engine design.
  - tinus_hn 3y ago
    It’s actually very easy if you are the government; you just say from 5 years from now, using lead fuel is banned. And then someone else has to do the work.
  - FireBeyond 3y ago
    Except... certification is done: https://www.aopa.org/news-and-media/all-news/2022/september/01/closer-to-an-unleaded-future https://www.aopa.org/news-and-media/all-news/2022/september/... > The FAA signed on September 1 supplemental type certificates that allow General Aviation Modifications Inc.’s 100-octane unleaded fuel (G100UL) to be used in every general aviation spark-ignition engine and every airframe powered by those engines. All piston engines and aircraft are certified for G100UL.
- lazide 3y ago
  It's a pretty dick move to ban something a large portion of the aviation community needs when there is literally no legal alternative no? There is now a legal alternative. Working as intended.
  - TSiege 3y ago
    Dick move to ban am additive that we've known for over a century has terrible toxic affects on people and the environment from a machine that would release it into the air? Maybe there isn't an alternative, but maybe it doesn't matter? Edit, looks like there is an alternative https://news.ycombinator.com/item?id=38040091 https://news.ycombinator.com/item?id=38040091
    - lazide 3y ago
      The amount of lead taken up from leaded avgas in the community is so close to zero (compared to other sources) that it hasn't outweighed the damage done by essentially banning general aviation. Which is what banning leaded avgas would do without an alternative. It's already nearly choked to death by regulation, but that was a step too far. But they also clearly have been working to mitigate it, and now that they have an alternate are banning leaded avgas and launching it. So what is your rant about exactly?
      - dicknuckle 3y ago
        You're going to need to provide a source for "the amount of lead taken up from leaded avgas in the community is close to zero" otherwise it's FUD.
        lazide 3y ago
        https://www.mayoclinic.org/diseases-conditions/lead-poisoning/symptoms-causes/syc-20354717# https://www.mayoclinic.org/diseases-conditions/lead-poisonin... Do you even see it in the list? This NIH study shows it as ‘small, but significant’ - accounting for anywhere from 2.1-4.4% of the lead found in children’s blood near piston airports. https://ehp.niehs.nih.gov/doi/10.1289/ehp.1003231 https://ehp.niehs.nih.gov/doi/10.1289/ehp.1003231 Less than 5% of the amount of lead total in their blood from that source, literally for the highest risk segment you can find. Even if completely eliminated, the other 95% isn’t going anywhere. Even if you don’t average it out across the population, it’s hard to argue that isn’t so close to zero that nearly any significant benefit anywhere else would make it not a rush. Most airborne lead pollution now is industrial anyway, and that is clearly the calculus there. As is the #1 and #2 sources of lead ingestion for children, old paint and old pipes. I’m glad they’re getting rid of it, but I’m not going to complain they didn’t drop everything to rush it. Especially since if they did, they’d almost certainly kill more people in the resulting plane crashes.
- mulmen 3y ago
  The FAA recently approved unleaded avgas. The EPA never had a problem with unleaded gas.
- SAI_Peregrinus 3y ago
  The FAA legalized unleaded avgas recently, yes. The EPA (the agency this article is about) was waiting for a legal alternative before banning leaded avgas. Since the EPA can't authorize a fuel for use in aviation (that's the FAA's jurisdiction) they had no choice but to wait on the FAA approval. Since the EPA can now ban the leaded fuel.
hollerith 3y ago
It's about time!
strangemonad 3y ago
Gee if only the FAA could have certified unleaded gas some time in the last 3 decades. It’s not like us GA enthusiasts enjoy depending on an expensive leaded gas.
- nimbius 3y ago
  as a diesel engine mechanic ive always figured there was some amazing conspiracy about leaded avgas. Here on the ground, diesel regulations and formulations are basically a yearly theatricality. new scrubbers, new regenerators, fuels you can use and fuels you can never use, and special locations and applications for the fuels if you use them at all. The regulations are pretty rigorously developed and enforced.
  - colechristensen 3y ago
    If your standard diesel engine fails it’s generally not a life threatening emergency though so change is much safer. Aviation has safety and regulatory habits written in blood.
    - ethbr1 3y ago
      Aren't most emergency backup generators diesel? Hospitals. Nuclear power plants. Airports. Laboratories.
      - dghlsakjg 3y ago
        Yes, but the GP is posting about diesel engines in over the road equipment. Those regulations don't apply to 1. existing installations in trucks or 2. generators.
      - mschuster91 3y ago
        These are multi redundant and generally hospital patient monitoring systems have additional batteries of their own to make sure people don't die, and in the case of a major clusterfuck there are emergency procedures in which it's specified how power will be restored assuming a grid and backup generator failure (usually it involves the fire department shuttling a generator pack to the hospital site). With engine failures in aircraft however, the consequences can be way more dire - particularly in GA where it's (at least in the US) even being allowed to fly without a license at all (Part 103 ultralights), and forget about regular legit simulator training on what to do in that case.
clbrmbr 3y ago
Wait, wasn’t leaded gas banned in the 70s? Are you telling me all these aircraft that fly over my house are filling the air with lead? How much environmental lead contamination are we talking here?
- sojournerc 3y ago
  Not all planes, just older ICE powered prop planes. Jets (and turbo-props) run on kerosene basically. The lead is an additive that acts as a lubricant and older engines aren't certified to run without it.
  - ledauphin 3y ago
    it's not actually primarily a lubricant, it's an octane-increaser (detonation reducer)
    - sojournerc 3y ago
      IIUC, it's both, but you're right lubrication is not it's primary purpose, but I think the reason leaded fuel is hard to replace is that the lubricating properties are difficult to replicate. > wherein it served as an effective antiknock agent and reduced exhaust valve and valve seat wear. https://en.m.wikipedia.org/wiki/Tetraethyllead https://en.m.wikipedia.org/wiki/Tetraethyllead
      - jabl 3y ago
        That's mostly an issue on cheap engines without hardened valve seats. Aviation engines switched to hardened valve seats well before WWII.
  - pc86 3y ago
    "older ICE powered prop planes" in this context means any prop plane, and about 95% of those used for GA. Brand new ones require leaded gasoline as well because with the exception of fuel injection the engine designs are basically identical to those 50s and 60s era planes.
some_random 3y ago
Glad to hear, it should have been phased out a long time ago. Assuming there aren't any issues with the only very recently legalized unleaded avgas I don't think there are any downsides.
tombert 3y ago
So I know absolutely nothing about chemistry, so can someone explain to me why lead was added to gasoline in the first place? Disregarding its toxicity, what benefit does lead buy you?
- savrajsingh 3y ago
  Allows higher compression of the fuel before it combusts. watch this: https://www.youtube.com/watch?v=IV3dnLzthDA https://www.youtube.com/watch?v=IV3dnLzthDA
- loeg 3y ago
  https://en.wikipedia.org/wiki/Tetraethyllead https://en.wikipedia.org/wiki/Tetraethyllead > It is a fuel additive, first being mixed with gasoline beginning in the 1920s as a patented octane rating booster that allowed engine compression to be raised substantially. This in turn increased vehicle performance and fuel economy.
- amarshall 3y ago
  Increases octane rating, that being is necessary to prevent engine knocking at higher engine compression ratios.
  - lawlessone 3y ago
    So higher octane means it needs higher temp/ pressure to burn? I've completely misunderstood octane my whole life.. i always thought it meant "high octane make engine brrrrrr fast"
    - bombcar 3y ago
      Higher octane allows it to get compressed more before it goes boom, which means you can make a more powerful engine. But adding high-octane gas to a normal engine doesn't make it go any more boom, in fact, it goes less boom because it doesn't burn as much when it booms. Modern engines can be designed to advance or retard timing based on knock, so they can run on different octanes and provide different power curves.
dlandis 3y ago
Could someone please summarize what the expected timeframe would be? How long until leaded avgas is not used?
- civilitty 3y ago
  It’ll probably take another 10-20 years to outright ban it. Though the EPA might make it illegal to manufacture any engines that use leaded gas far sooner than that. Now that there is an unleaded alternative, older planes will slowly replace their engines at the next engine rebuild. There is a grave pilot shortage already and the FAA loathes to make GA even more inaccessible than it already is so it’ll be a slow process.
  - pc86 3y ago
    > older planes will slowly replace their engines at the next engine rebuild An alternative exists, but the FAA needs to certify it for each aircraft type. The majority of aircraft types are not certified for this. No A&P is going to do this because the plane won't be legal to fly in most cases. And at the risk of editorializing, I've never seen the FAA do anything with the goal to making GA more accessible, at least not intentionally.
    - phkahler 3y ago
      >> An alternative exists, but the FAA needs to certify it for each aircraft type. They have. It's done. nobody needs to worry about liability for switching. Availability will be a short-term problem, and banning leaded fuel will get it fixed quickly. https://www.g100ul.com/ https://www.g100ul.com/
      - lazide 3y ago
        They were talking about changing out engines for the planes, not the fuel.
        phkahler 3y ago
londons_explore 3y ago
How many IQ points did the nation lose because of this delay?
- AlgorithmicTime 3y ago
  [dead]
- JWoolfenden 3y ago
  so many i can't count...
- hotnfresh 3y ago
  In general? Probably not measurable. In neighborhoods or cities that happen to sit under take-off or approach paths for, or downwind of, very-busy airports that see a lot of prop plane traffic? Maybe a measurable amount.
  - russdill 3y ago
    I'm be most concerned about people that deal directly with the fuel and infrastructure.
    - londons_explore 3y ago
      I'm concerned about everyone. When you start getting lead into corn and wheat, it gets into flour and bread and pasta, and before long, everyone has eaten some. Sure - some have eaten more, and others less. But everyone has been impacted. Half of the US population has blood lead levels above the CDC 'safe' level.
      - fsckboy 3y ago
        > Half of the US population has blood lead levels above the CDC 'safe' level. That's a bogus statistic. I went to look up what you could be talking about, and it appears to be pretty shoddy alarmism, not on your part but poorly or shadily written reports. (disclaimer/reassurance: Lead is bad for us, and heavy metal exposures are cumulative over a lifetime, so the lower the better, and we should keep lowering.) But what you quoted implies that we are not succeeding quickly enough, and from things I looked at, that is not a conclusion that can be drawn. I didn't spend a lot of time on it, but just from a few headlines and an abstract, it's clear that the lead levels under consideration have been lowered recently (and for what I'm about to say, undoubtedly previously lowered other times), and are not toxicity levels but more like "hey, there's lead in this neighborhood". And the lead exposures they are talking about are "retroactively" encompassing the elderly who were exposed as children before the new levels (and unleaded gas) were a thing. So, they're saying "Among the entire population, half of people have previously received during childhood lead exposures when we didn't have current standards that we would now consider to be, not even unsafe, but where geographically we should focus our attention looking at the sources." --- sources: https://www.cdc.gov/nceh/lead/news/cdc-updates-blood-lead-reference-value.html https://www.cdc.gov/nceh/lead/news/cdc-updates-blood-lead-re... 2021, CDC updated the blood lead reference value (BLRV) from 5.0 μg/dL to 3.5 μg/dL. A BLRV is intended to identify children with higher levels of lead in their blood compared with levels in most children... It is not a health-based standard or a toxicity threshold... should be used as a guide to 1) help determine whether medical or environmental follow-up are recommended and 2) prioritize communities with the most need for primary prevention of exposure. .. BLRV is a population-based measurement that now indicates that 2.5% of U.S. children aged 1–5 years have BLLs at or above 3.5 μg/dL. https://pubmed.ncbi.nlm.nih.gov/35254913/ https://pubmed.ncbi.nlm.nih.gov/35254913/ Considerable effort is expended to protect today's children from lead exposure, but there is little evidence on the harms past lead exposures continue to hold for yesterday's children, who are victims of what we term legacy lead exposures. We estimate that over 170 million Americans alive today were exposed to high-lead levels in early childhood, several million of whom were exposed to five-plus times the current reference level [which is not a health or toxicity level]. Our estimates allow future work to plan for the health needs of these Americans and to inform estimation of the true contributions of lead exposure to population health. We estimate population-level effects on IQ loss and find that lead is responsible for the loss of 824,097,690 IQ points as of 2015. ...and you can't add IQ points like that, most especially if you are part of the substantial segment of the population that says that IQ is a bogus measurement, a segment that heavily overlaps with environmentalism.
lawlessone 3y ago
Damn. The chemtrails people were right. For all the wrong reasons.
- nonsense123 3y ago
  It's no accident. Spin doctors work in strange ways, but they do work.
w10-1 3y ago
It's complicated. Overall it's better to do most anything to protect kids' development, but doing so is tough. Leaded avgas mainly benefits turbines, which are a minority of GA planes but the majority of avgas users, because they're the always-running commercial subset. The benefit is in time between overhauls. Every replacement fuel has resulted in more engine deposits and more maintenance -- essentially requiring $20K overhauls at 1,500 hours instead of 3K. For non-turbine GA, typically age catches up to the engine before hours, but for commercial turbines it can be a make-or-break decision, since a company might own only one or two. Reid-Hillview airport in San Jose is an example of an airport closed over leaded fuel concerns, because they reportedly found an increase in lead in children's blood in a few who lived right next to the airport. That increase was minimal compared to elevated levels found in Oakland and elsewhere due to ingestion of 60+-year-old leaded paint, but it's essential to remove whatever sources there are. The EPA has often complained, but the FAA has persisted. This particular move is noise before the next election (timed for the just-approved FAA appointee). It's unclear if it will result in anything faster than the decades-delayed process already in play, but it does give communities huge leverage in their lawsuits. Local airports often have a lot of land being used for essentially nothing. When local communities take federal money to develop or maintain airports, they legally agree that the airport is to remain in near-perpetuity. It can take decades of refusing federal money to get out from those obligations. The redevelopment opportunity presented by closing an airport in San Jose or Santa Monica is in the billions of dollars. So there are strong economic interests supporting anything that turns a community against the local airport. And since few people want to have planes overhead, those neighborhoods are typically lower-income and often under-represented politically, raising environmental justice concerns and making for concealed politics as monied interests fund advocacy campaigns and scientific research. Commercial turbine operators, GA owners, and local businesses using general aviation typically have fixed assets that commit them to protecting the airport. The price of avgas runs 50-150% over automotive fuel. For refiners, it's a production shift and a run that lasts 1-2 weeks per year (and hence some storage costs as well). They also have fixed assets, though distribution networks have in some cases been outsourced in anticipation of moving in or out of the avgas market. They do it mostly to keep people happy, since it's not a big profit maker. A big issue is ethanol. It's seasonally mixed into automotive fuel almost everywhere, but it attacks most of the current fuel systems. With engine re-certification for avgas, there are only 1-3 manufacturers running a few engines through time on test beds and some pilot programs. That's much, much easier than retrofitting fuel systems of many, many models of planes. In most cases, the manufacturer is no longer in operation, or they would love to see the old planes die so they can sell new ones (often having bought minimal name and assets out of bankruptcy). Electric is unlikely to replace turbine ICE unless the energy density improves in ways that would transform the entire world. It's more likely smaller jet engines could replace them, but it's not clear who would do that engineering for a relatively small market. So a pessimistic prediction is that this might help some local land grabs, but is not likely to help a lot of kids. Let's hope for more than that.
leadtester 3y ago
[dead]
mattmaroon 3y ago
I’ve never met a group more resistant to change than GA enthusiasts. They think they have a God-given right to fly the same way they did in the 1940’s. I was getting into it right as the ADS-B rules were coming into play. It is a cheap and easy (by aviation standards anyway) technology designed to prevent mid air collisions, and you’d have thought the FAA was requiring them to murder their children.
- stouset 3y ago
  Hell, some pilots insist on continuing to fly without radios.
  - salusinarduis 3y ago
    There's a strong overlap of these people also doing stupid stuff like flying near and on the final approach courses of instrument approaches.
- deleted 3y ago
  [deleted]
- mattgrice 3y ago
  change has only ever been bad for GA. GA is now just a really expensive sport for old people who bought their planes 40 years ago when Beechcraft ran ads in National Geographic. Of course they are going to be resistant to change, and possibly rightfully so because GA is 1 or 2 steps away from being completely dead.
  - bradley13 3y ago
    No sympathy. Where I live, there are strong noise restrictions on holidays and Sundays. A huge proportion of the population support this - it is very nice to have days without lawnmowers, chainsaws or whatever. Who is exempt? Aviation. One plane makes noise over tens of thousands of people. The absolute worst are the stunt planes.
  - ryandrake 3y ago
blahyawnblah 3y ago
Do aviation engines required hardened valve seats like automotive engines did for the changeover?
- bluGill 3y ago
  Maybe. Most automotive engines ran just fine for a normal lifespan without changing the valve seats. When you work the engine hard you need it, but if you are not racing you generally got by with it. Of course the change for automotive was the early 1980s when engines were not as reliable and didn't last as long. Don't forget that aviation engines are require a lot of regular rebuilds. In a car you wait until something breaks, in an airplane you replace parts long before they might fail to ensure it doesn't break when in the air. So for many we can just add replace the seats/valves in the next tear down and be okay.
- jabl 3y ago
  Practically all aviation engines have used hardened valve seats since even before WWII. Maybe some WWI era engines didn't have them, I'm not sure.
kortex 3y ago
Why are diesels so uncommon among piston aircraft, it's almost always avgas? Is it just "because that's how it's always been" or are there actual engineering reasons diesel are inferior? Cursory searching suggests it's mostly this inertia. It'd be especially useful if they could run on regular jet fuel, then turboprops/jets and pistons could use the same fuel infra.
- russdill 3y ago
  There's a number of difficult engineering tradeoffs. Engines that can run on diesel typically need to be heavier.
- PumpkinSpice 3y ago
  Diesel engines operate at higher pressures and must be considerably heavier to achieve the same performance & efficiency. Not a huge issue for ships, trains, or cars. Huge issue for flying stuff.
- jacquesm 3y ago
  Power to weight ratio. Diesel engines tend to be cast iron rather than aluminum.
- jabl 3y ago
  As others mentioned, diesels tend to have worse performance/weight due to heavier construction. In the early days of aviation (like 1930's or such) there was some effort to introduce diesels for long-range aircraft, the idea being that the heavier powerplant would be offset by the lower required fuel load due to better fuel economy. But they weren't successful. More recently there has been something of a renewed interest in aviation diesel engines, the motivation being they can run on Jet A-1 in addition to diesel fuel. Jet A-1 is what jet (and turboprop) aircraft use, and is available at basically every airport worldwide, is much cheaper than avgas, and no risk of being phased out like the leaded avgas being discussed in this article.
- papa-whisky 3y ago
  As the sibling comments have pointed out, power-to-weight is the main reason, but it doesn't make diesel engines completely unfeasible for light aircraft. Diamond Aircraft have had success selling planes with diesel engines recently, and even started a subsidiary company to manufacture them: https://en.wikipedia.org/wiki/Austro_Engine https://en.wikipedia.org/wiki/Austro_Engine
__MatrixMan__ 3y ago
Oh, this is fuel we're talking about. I was imagining lead somehow involved in lifting gas, like a leaded zeppelin or somesuch.
RecycledEle 3y ago
[flagged]
- digitalsushi 3y ago
  Would you consider elaborating upon this? I don't have a reason to doubt you, but I am also picturing the people who fly airplanes as being sympathetic to older machines. And I'm in that camp of unscientific people who figure a 23 old truck (specifically using unleaded fuel) that doesn't need to be rebuilt anew is actually kinder to the earth than the alternative.
  - RecycledEle 3y ago
    I remember the legal precedent set during the trial of US President Bill Clinton. He claimed the law he was being sued under (sexual harassment) was unconstitutional, which it was. The problem was that he signed it into law, and not even The President can not be that big of a hypocrite in an American court room. So he lost. If someone is blatantly hypocritical, I have a great desire to hoist them with their own petard (to use their argument against them.) Since the people who fly the largest private planes openly demand I stop driving my old pickup, I make the much more moderate demand that their airplanes meet each and every single emissions and fuel economy requirement that my old pickup has had to meet to stay on the road all these years. I 100% support grounding all civilian air travel, world wide. I would give them the same time I would have if my old pickup failed an inspection to come up to standards, or their planes would be scrapped. Good luck to them getting catalytic converters on jet engines.
- jlmorton 3y ago
  No need to ban it, but I'm happy to support a carbon tax on aviation equivalent to the current market cost of CCS, so something like $200/t. So, for instance, Elon Musk's private jet is estimated to have emitted 2,112 tons in 2022. Elon would have to pay a $400,000 carbon tax. Ideally these taxes would flow through fuel, but that presents some challenges, since planes can re-fuel in jurisdictions without those taxes, although that's certainly harder to do in the United States. I think in the US, it might be hard enough to do that that just taxing the aviation fuel is fine.
ouiouibaguette 3y ago
I live near a lake that sees a lot of floatplane takeoffs. I wonder how many IQ points were lost among the rich folks with lakefront properties.
dadjoker 3y ago
Shorter EPA: "Look, here's one more way we can cripple our economy! Yea!"
- skeaker 3y ago
  If that's the only angle you care about, then consider that a population free of lead-induced brain damage provides a stronger economy in the long run as more of them are able to enter the workforce rather than prison [1] or a grave [2]. [1] https://en.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis https://en.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis [2] https://en.wikipedia.org/wiki/Lead_poisoning https://en.wikipedia.org/wiki/Lead_poisoning
- elif123 3y ago
  [flagged]
Robotbeat 3y ago
Good
bradley13 3y ago
Huh? Leaded fuel or recently produced engines? Honestly, that's shockng. Zero excuse, should have been outlawed decades ago.
- deleted 3y ago
  [deleted]
briandear 3y ago
Perhaps the FAA could remove the requirement to buy an STC to use unleaded fuel? If they want wider adoption, removing the STC requirement would help.
- jabl 3y ago
  I suspect what needs to happen is that someone (ASTM?) comes up with a spec for unleaded 100 octane avgas, and then the FAA can give a blanket approval for that spec for any plane certified for 100LL.
  - sokoloff 3y ago
    Can't (realistically) be done. The specification for most airplane engines say "100LL" and the specification for 100LL is a composition specification (ASTM D 910), not a performance specification. If your fuel meets ASTM D 910, it contains lead. If it doesn't contain lead, it doesn't meet ASTM D 910 and therefore definitionally isn't 100LL, so if your engine type certificate data sheet calls for 100LL, it unavoidably calls for lead. If you are flying an aircraft that is thus-certified, flying it with a different fuel is, per the FAA definition in 14CFR3.5, flying an unairworthy airplane. "Airworthy means the aircraft conforms to its type design and is in a condition for safe operation." That's the legal reasoning that the Gami STC is required: to change the TCDS of the engine and airframe to permit a fuel other than 100LL and still be considered airworthy. (The STC process is totally workable and, IMO, doesn't need to be "fixed" and Gami has basically done the work you're asking to be done AFAICT.)
    - jabl 3y ago
      Weren't many of the planes in operation today certified before 100LL became the only available grade (excluding things like 115/145 or even more exotic brews which I guess today are used only at Reno air races and such)? E.g. 80/87 for lower performance engines, and 100/130 for higher performance ones. So presumably they were somehow grandfathered in when 100LL replaced these grades? So why can't the same be done for a hypothetical "100UL" spec?
DigiDigiorno 3y ago
The uphill battle of unleaded avgas leaves both the main players in the industry and the regulators themselves looking bad—but in a banal kinda way. I enjoy AVWeb on YT for AV news (really, I just enjoy the humor/personality of Paul Bertorelli lol), here are a few insightful videos that summarize the story: The Long, Twisted And Slightly Ridiculous Story of Avgas Part 1 (14:22) https://www.youtube.com/watch?v=9F-WngVMJBQ https://www.youtube.com/watch?v=9F-WngVMJBQ Part 2 (15:15) https://www.youtube.com/watch?v=Mvse4Xhzwuk https://www.youtube.com/watch?v=Mvse4Xhzwuk and G100UL Approved Now What? (When the FAA approved the first unleaded 100-octane avgas a year ago) https://www.youtube.com/watch?v=ibIkuyBL9i8 https://www.youtube.com/watch?v=ibIkuyBL9i8
donbatman 3y ago
Any aircraft mechanics care to comment on this? I know lots of small privately owned aircraft are really really old. Like 50s or 60s or older. Is this going to screw up their fuel system gaskets and seals?
oldbbsnickname 3y ago
TEL is incredibly bad stuff*, but it's rarely used in commercial flight operations as they predominantly use jet aircraft. Leaded avgas is completely unnecessary as non-TEL fuel formulations have been created and certified. The problem is they're not available anywhere, while leaded avgas is everywhere in GA. Municipalities should do like they did for leaded automotive gasoline: supersede commercial interests with public health regulatory ones and ban it. (The EPA only banned leaded automotive gasoline nationwide in 1996 after allowing 25 years for the phaseout.) * In the same category of human harm as nerve agents, dioxin, and methylmercury. https://www.aopa.org/news-and-media/all-news/2021/july/27/gami-receives-unleaded-avgas-stc https://www.aopa.org/news-and-media/all-news/2021/july/27/ga... https://www.epa.gov/archive/epa/aboutepa/epa-takes-final-step-phaseout-leaded-gasoline.html https://www.epa.gov/archive/epa/aboutepa/epa-takes-final-ste...
- lazide 3y ago
  The first general purpose non-TEL alternative was only certified last year. Before that, each variant had to be certified per-type, and then would need to be stocked everywhere. Which never was going to happen, and didn't. Now they're going to ban leaded avgas, which should force the for adoption, since there IS now an approved general purpose alternative.
archsurface 3y ago
"Finding that pollutions from aircraft engines contribute to air pollution".
trhway 3y ago
Waiting for the Tesla of the aviation as that lead vs. unleaded feel like something ancient. Lets look at numbers as of today: Cesna 172 - 75kw engine, on 50kw power makes 1000km as 200km/hr. Engine plus fuel weight 350kg. The engine costs $26K. Today's lithium batteries like ones used by Tesla is 280wh/kg. At retail similar batteries cost $400/kwh. So, we can have 75kw electric engine and 100kwh battery at the same weight as ICE engine plus fuel on Cesna 172 and at a retail cost of $50K and have 2 hr flight of 400km. That isn't a worse starting point than what Tesla had 15 years ago against ICE cars.
- lazide 3y ago
  Now add several thousand lbs of paperwork, and some absolutely insane liability court precedent [https://www.ainonline.com/aviation-news/2007-11-27/cessna-found-liable-480m-crash-185 https://www.ainonline.com/aviation-news/2007-11-27/cessna-fo...], and you'll see why it hasn't happened yet.

450 points by Metacelsus 3y ago

thumbs up.

Didn't they just legalize unleaded avgas very recently? After a multi-decade regulatory review process? Seems odd that they were so hesitant to legalize it and now that they did, it becomes the only option!

Kapura 3y ago
The only odd part is that it took so long. Leaded gasoline has been known to be toxic for many, many decades.
crazygringo 3y ago
Or it makes perfect sense. Once it's legal, what reason is there to keep the poisonous one around? It's not odd, it's exactly what you'd expect. The only odd thing is that it took this long.
- TinyRick 3y ago
  > Once it's legal, what reason is there to keep the poisonous one around? Many (older) aircraft engines need leaded fuel.
  - kevan 3y ago
    I remember news saying the FAA added supplemental type certs allowing G100UL for basically every engine in 2022. What gaps are there?
    - sokoloff 3y ago
      Distribution. https://www.g100ul.com/faq.html#availability https://www.g100ul.com/faq.html#availability
  - mlyle 3y ago
    As far as we know, G100UL works in anything.
    - labcomputer 3y ago
      Yes, but it's not currently legal to use in anything. You still have to apply for and buy an STC for your specific airframe's serial number and engine's serial number. Then you have to add some paperwork to the logbook and POH and add placards to the fuel fillers and cockpit. In theory you should be able to automatically get it for anything which was approved from the factory to use 100LL, but the STC application form (here: https://stc.g100ul.com/aircraft/ https://stc.g100ul.com/aircraft/) does not allow you to select most mid-century large radials (which were usually originally certified on 130) or the airplanes they were installed on. To be clear, this is a great thing, but you can't legally just fill G100UL in any random airplane.
      - briandear 3y ago
        Exactly. Remove the STC requirement. If the fuel is unreliable that it won’t work in every 100LL aircraft, then it shouldn’t be forced upon us. If it is completely safe, then an STC should be unnecessary.
        mlyle 3y ago
        What about something in-between? The fuel is reliable in almost every design, but there's some design out there that -relies- upon lead depositing to engine surfaces to be reliable (as opposed to the octane effect). I don't think it needs to work in every conceivable 100LL aircraft: just almost all. Every is a high bar.
        lazide 3y ago
        Which is why it is taking so long. Because if an engine grenades on takeoff, it's almost guaranteed to kill someone. If that was because of the fuel switch, that's a real problem.
        3y ago
  - tastyfreeze 3y ago
    Can't upvote this enough. This is going to kill small operators that might not be able to comply. Why not just let the leaded fuel users die from attrition naturally?
    - aaomidi 3y ago
      Because lead is not safe? Like small planes are spewing lead over everywhere they’re flying. I’m glad this is happening. I don’t really care about small operators vs the health of everyone else, and especially kids in the case of lead.
    - munk-a 3y ago
      Considering we're talking about leaded fuel that is some terrible wording.
      - aaomidi 3y ago
        I know right? Operating a plane is a privilege, not a right.
        lazide 3y ago
        So, apparently, is operating a motor vehicle. Except large swathes of the economy will collapse without them. Oh, we aren't talking about tire dust? Never mind.
        eesmith 3y ago
        Then let's talk about it. Unlike lead, we've only recently had the technology to measure and quantify tire wear pollution. For example, we didn't realize until 2020 that 6PPD - already toxic to many aquatic organisms - can oxidize become 6PPD-quinone, which is acutely toxic to coho salmon and some other fish species. This solved a 20 year old mystery of so many coho salmon died after a rain storm. That's why the California Environmental Protection Agency has passed a rule requiring tire makers to declare an alternative by 2024. https://dtsc.ca.gov/scp/motor_vehicle_tires_containing_6ppd/ https://dtsc.ca.gov/scp/motor_vehicle_tires_containing_6ppd/ That's in addition to the particulate pollution from tire wear. ("Research from Emissions Analytics shows that particulate mass emissions from tire wear is thousands of times greater than those from tailpipes, which have been vastly reduced in recent years by high-efficiency exhaust filters." - https://edition.cnn.com/2022/08/16/world/tyre-collective-microplastic-rubber-waste-climate-hnk-spc-intl/index.html https://edition.cnn.com/2022/08/16/world/tyre-collective-mic... ). We of course need to regulate them better because electric cars are heavier, so tire particulate pollution is expected to increase over the next few years. There's also brake pad pollution, like the EPA's Copper-Free Brake Initiative to remove copper, "mercury, lead, cadmium, asbestiform fibers, and chromium-six salts in motor vehicle brake pads." https://www.epa.gov/npdes/copper-free-brake-initiative https://www.epa.gov/npdes/copper-free-brake-initiative . That's a voluntary program, but California and Washington have mandatory requirements. I trust that you support these efforts to reduce car pollution, and are not simply using the lack of discussion about them in this thread in order to score internet points for implied hypocrisy? Both tires and brakes have the advantage that they are replaced every few years/decade, so regulations can target manufacturers. An aircraft engine can have decades of life, so any costs of switching away from leaded fuel are felt directly by the owner.
  - dontlaugh 3y ago
    Any petrol engine can run on 100 RON fuel. There are several options that involve no lead, generally substituting with ethanol.
    - labcomputer 3y ago
      Sure, and any petrol engine can run on 78 RON fuel to. It's just that if you try to run it at full power you'll blow it up. Wee bit of a problem on takeoff. Same thing with running certain large piston airplane engines on 100. They blow up. > There are several options that involve no lead, generally substituting with ethanol Ethanol is corrosive to aluminum. Thankfully airplane designers have never used aluminum in airplanes...
    - mchid 3y ago
      We can't use ethanol because of phase separation amongst other reasons but this is true considering we've been using stuff like toluene probably even longer than tel.
  - kube-system 3y ago
    They don't "need" lead any more than pre-70s cars "need" lead. They were designed to run on leaded fuel, but there are lead replacement additives which are able to fulfill the same technical requirements. TEL is just cheap, effective, and well understood for legacy applications. It isn't the only option to boost octane, by far.
    - roflchoppa 3y ago
      The only issue I had on my 240z was the valve seats were some super soft brass like material, those needed to be swapped as they were beat to up and did not seal. The 75+ heads, all have steel seats. I’ve actually never experienced the, “California gas sucks” issue that car people from the mid-west talk about, have never had an issue with it. ¯\_(ツ)_/¯
      - mcronce 3y ago
        Maybe my understanding is incomplete, but AFAIK the "California gas sucks" thing is just because the highest grade you can find at most pumps there is 91, while we get 93 in a lot of other states Not that it matters when everything made for "premium" is tuned for 91 from the factory anyway, not 93
        arcticbull 3y ago
        California actually has different gas that produces fewer emissions - it's part of the reason gas is more expensive here. It's called CARBOB grade, c.f. RBOB/CBOB.
        dicknuckle 3y ago
        Today I learned, thanks!
        mcronce 3y ago
        TIL, thanks for the info
        3y ago
  - lfuller 3y ago
    G100UL, the current unleaded alternative to 100LL, has been tested to act as a drop-in replacement for any and all aircraft engines that run on 100LL. If you can run, 100LL, you can run G100UL. The main issue is with mogas (standard car gas) - many aviation engines can't run it.
    - jacquesm 3y ago
      Is that due to the Ethanol fraction or some other factor?
      - i386 3y ago
        From memory octane levels have a huge bearing on engine performance and that affects take off distance. Aviation has had a much higher octane rating than your typical car gas.
      - ctennis1 3y ago
        A myriad of things: Octane, ethanol, and also additives used in the winter vs the summer.
      - labcomputer 3y ago
        That's part of it. Ethanol is incompatible with materials commonly found in airplane fuel systems. Another aspect is that many piston airplane engines need high octane because they have relatively high compression ratios: WWII era engines need 130 octane to develop full horsepower (they can be operated at reduced manifold pressure on currently available 100 low-lead gas), and even many post-war civilian engines require 100 octane. Still another aspect is that the FAA is relatively conservative and doesn't want to approve something that might lead to, for example, vapor lock or fuel freezing issues.
        mrguyorama 3y ago
        >airplane engines need high octane because they have relatively high compression ratios: WWII era engines need 130 octane to develop full horsepower I mean, high octane and compression relative to other 1960s engines. The common engines in nearly any single prop cessna have about a 9:1 compression ratio, which was massive back when it was built, but laughably bad compared to anything manufactured after the advent of Fuel injection and better piston geometry. Modern cars regularly have over 12-1 compression ratios on 87 octane. 1960s era carbs and top ends were just abysmal and did a terrible job of mixing the fuel and air charge and controlling the flame front, because we just didn't have the kinds of computer controls and fluid dynamic simulations we have now, to dynamically prevent knock. Rotax engines are modern and can reach identical performance figures or better, with the same weight or lighter, simply by using modern techniques like fuel injection or a small turbocharger. They do this while running on 91 octane
  - heelix 3y ago
    The beauty of G100UL is you just need an STC - just paperwork - to be legal with GA aircraft. All gasoline powered aircraft and engines in the FAA’s type certificate database are covered by the STC for G100UL... which is amazing. I'll be doing it, as soon as our home base carries it for my 56 o200.
  - mchid 3y ago
    They literally don't when G100UL exist, which is approved as a full drop in replacement safe for all engines.
foxyv 3y ago
Mostly because the use of lead in fuels is something to avoid at all costs. I know a lot of GA people were VERY happy to hear that they approved G100UL. Leaded fuels aren't just toxic, but they also cause issues with airplanes such as lead fouling. AVWeb did a couple videos on the subject here: https://youtu.be/9F-WngVMJBQ?si=Qb_IYu4QwZlOTDCv https://youtu.be/9F-WngVMJBQ?si=Qb_IYu4QwZlOTDCv https://youtu.be/ovJBJjZTjsk?si=f2OwwZMmuEUTx6wL https://youtu.be/ovJBJjZTjsk?si=f2OwwZMmuEUTx6wL
codexb 3y ago
The problem is that they won't approve engines for general aviation that use unleaded gas. All the engines used in general aviation are basically 60 year old designs. General aviation is not a major concern for the FAA. It's an afterthought. And so they don't devote any time to approving new, modern engines and make it as difficult as possible.
- phkahler 3y ago
  >> The problem is that they won't approve engines for general aviation that use unleaded gas. Except that they did approve a lead-free fuel for use in all those engines last year. Banning leaded fuel is the obvious next step.
- jabl 3y ago
  Many, or even most, of the engines are indeed old designs. But e.g. Rotax offers certified version of some of its 900 series engines, which are a relatively new design, some with fuel injection, FADEC, etc.
phkahler 3y ago
>> Didn't they just legalize unleaded avgas very recently? More specifically, I believe they certified that a particular fuel as suitable for use in ALL engines that previously relied on leaded fuel. Until that happened there was a somewhat legit concern about banning leaded fuel. What people are afraid of now is a monopoly on the new fuel leading to higher prices. But there's already a near monopoly on leaded avgas. It would be really cool if someone developed a new aircraft engine suitable for replacing all the old models and able to run on a wide range of fuels (this may actually exist). But even then its a slog to get that engine certified for all the planes you'd want to use it on.
- marcosdumay 3y ago
  > It would be really cool if someone developed a new aircraft engine suitable for replacing all the old models and able to run on a wide range of fuels As a recent article here talked about, nobody is making new aircraft for general aviation. Or at least, nobody is making anything innovative for it. But there exist plenty of engines that are good enough for planes and can run on a wide range of fuels. They are just not getting into GA planes.
  - SoftTalker 3y ago
    There is some interesting stuff happening in battery-electric aircraft as trainiers. You can only fly them about 45 minutes and within a local radius of the airport but they are good for people learning the stick-and-rudder basics of flying.
    - MrDrMcCoy 3y ago
      Gliders are even better for learning flight basics, do a better job of teaching you to anticipate and work with turbulence, and have a variable time limit.
      - lazide 3y ago
        Glider hours aren't going to count towards any useful type certification though? Unless you think someone is going to be qualified on a Twin Otter because of 1000 glider hours?
SomeHacker44 3y ago
Availability of the new unleaded fuel is extremely limited. It is also very expensive. I also believe there may be a fee involved per airplane to use it (one time for an STC). The fee I heard is nominal $250. I have never flown to an airport with it yet. i have probably landed in over a dozen different airports in the last few months with a leaded gas engined plane.
- outworlder 3y ago
  > I also believe there may be a fee involved per airplane to use it (one time for an STC). The fee I heard is nominal $250. What is $250 in aviation terms? It's nothing. Availability of fuel is a concern, sure. But a fire has to be lit on people's ass, otherwise they will not move.
- scarby2 3y ago
  the requirement for the STC on a per-aircraft basis is now gone AFAIK. That was the effect of the FAA's "legalization" last year.
  - sokoloff 3y ago
    You still have to purchase the STC for your airplane serial number and engine(s) serial number. What the FAA did was approve that all-model STC as being valid/legal to sell and "install" (which is just placards).
TylerE 3y ago
The problem is, "legalizing" it is like 0.1% of the work. The hard part is all the testing/certification you have to do for every single aircraft and engine design.
- tinus_hn 3y ago
  It’s actually very easy if you are the government; you just say from 5 years from now, using lead fuel is banned. And then someone else has to do the work.
- FireBeyond 3y ago
  Except... certification is done: https://www.aopa.org/news-and-media/all-news/2022/september/01/closer-to-an-unleaded-future https://www.aopa.org/news-and-media/all-news/2022/september/... > The FAA signed on September 1 supplemental type certificates that allow General Aviation Modifications Inc.’s 100-octane unleaded fuel (G100UL) to be used in every general aviation spark-ignition engine and every airframe powered by those engines. All piston engines and aircraft are certified for G100UL.
lazide 3y ago
It's a pretty dick move to ban something a large portion of the aviation community needs when there is literally no legal alternative no? There is now a legal alternative. Working as intended.
- TSiege 3y ago
  Dick move to ban am additive that we've known for over a century has terrible toxic affects on people and the environment from a machine that would release it into the air? Maybe there isn't an alternative, but maybe it doesn't matter? Edit, looks like there is an alternative https://news.ycombinator.com/item?id=38040091 https://news.ycombinator.com/item?id=38040091
  - lazide 3y ago
    The amount of lead taken up from leaded avgas in the community is so close to zero (compared to other sources) that it hasn't outweighed the damage done by essentially banning general aviation. Which is what banning leaded avgas would do without an alternative. It's already nearly choked to death by regulation, but that was a step too far. But they also clearly have been working to mitigate it, and now that they have an alternate are banning leaded avgas and launching it. So what is your rant about exactly?
    - dicknuckle 3y ago
      You're going to need to provide a source for "the amount of lead taken up from leaded avgas in the community is close to zero" otherwise it's FUD.
      - lazide 3y ago
        https://www.mayoclinic.org/diseases-conditions/lead-poisoning/symptoms-causes/syc-20354717# https://www.mayoclinic.org/diseases-conditions/lead-poisonin... Do you even see it in the list? This NIH study shows it as ‘small, but significant’ - accounting for anywhere from 2.1-4.4% of the lead found in children’s blood near piston airports. https://ehp.niehs.nih.gov/doi/10.1289/ehp.1003231 https://ehp.niehs.nih.gov/doi/10.1289/ehp.1003231 Less than 5% of the amount of lead total in their blood from that source, literally for the highest risk segment you can find. Even if completely eliminated, the other 95% isn’t going anywhere. Even if you don’t average it out across the population, it’s hard to argue that isn’t so close to zero that nearly any significant benefit anywhere else would make it not a rush. Most airborne lead pollution now is industrial anyway, and that is clearly the calculus there. As is the #1 and #2 sources of lead ingestion for children, old paint and old pipes. I’m glad they’re getting rid of it, but I’m not going to complain they didn’t drop everything to rush it. Especially since if they did, they’d almost certainly kill more people in the resulting plane crashes.
mulmen 3y ago
The FAA recently approved unleaded avgas. The EPA never had a problem with unleaded gas.
SAI_Peregrinus 3y ago
The FAA legalized unleaded avgas recently, yes. The EPA (the agency this article is about) was waiting for a legal alternative before banning leaded avgas. Since the EPA can't authorize a fuel for use in aviation (that's the FAA's jurisdiction) they had no choice but to wait on the FAA approval. Since the EPA can now ban the leaded fuel.

hollerith 3y ago

It's about time!

strangemonad 3y ago

Gee if only the FAA could have certified unleaded gas some time in the last 3 decades. It’s not like us GA enthusiasts enjoy depending on an expensive leaded gas.

nimbius 3y ago
as a diesel engine mechanic ive always figured there was some amazing conspiracy about leaded avgas. Here on the ground, diesel regulations and formulations are basically a yearly theatricality. new scrubbers, new regenerators, fuels you can use and fuels you can never use, and special locations and applications for the fuels if you use them at all. The regulations are pretty rigorously developed and enforced.
- colechristensen 3y ago
  If your standard diesel engine fails it’s generally not a life threatening emergency though so change is much safer. Aviation has safety and regulatory habits written in blood.
  - ethbr1 3y ago
    Aren't most emergency backup generators diesel? Hospitals. Nuclear power plants. Airports. Laboratories.
    - dghlsakjg 3y ago
      Yes, but the GP is posting about diesel engines in over the road equipment. Those regulations don't apply to 1. existing installations in trucks or 2. generators.
    - mschuster91 3y ago
      These are multi redundant and generally hospital patient monitoring systems have additional batteries of their own to make sure people don't die, and in the case of a major clusterfuck there are emergency procedures in which it's specified how power will be restored assuming a grid and backup generator failure (usually it involves the fire department shuttling a generator pack to the hospital site). With engine failures in aircraft however, the consequences can be way more dire - particularly in GA where it's (at least in the US) even being allowed to fly without a license at all (Part 103 ultralights), and forget about regular legit simulator training on what to do in that case.

clbrmbr 3y ago

Wait, wasn’t leaded gas banned in the 70s? Are you telling me all these aircraft that fly over my house are filling the air with lead? How much environmental lead contamination are we talking here?

sojournerc 3y ago
Not all planes, just older ICE powered prop planes. Jets (and turbo-props) run on kerosene basically. The lead is an additive that acts as a lubricant and older engines aren't certified to run without it.
- ledauphin 3y ago
  it's not actually primarily a lubricant, it's an octane-increaser (detonation reducer)
  - sojournerc 3y ago
    IIUC, it's both, but you're right lubrication is not it's primary purpose, but I think the reason leaded fuel is hard to replace is that the lubricating properties are difficult to replicate. > wherein it served as an effective antiknock agent and reduced exhaust valve and valve seat wear. https://en.m.wikipedia.org/wiki/Tetraethyllead https://en.m.wikipedia.org/wiki/Tetraethyllead
    - jabl 3y ago
      That's mostly an issue on cheap engines without hardened valve seats. Aviation engines switched to hardened valve seats well before WWII.
- pc86 3y ago
  "older ICE powered prop planes" in this context means any prop plane, and about 95% of those used for GA. Brand new ones require leaded gasoline as well because with the exception of fuel injection the engine designs are basically identical to those 50s and 60s era planes.

some_random 3y ago

Glad to hear, it should have been phased out a long time ago. Assuming there aren't any issues with the only very recently legalized unleaded avgas I don't think there are any downsides.

tombert 3y ago

So I know absolutely nothing about chemistry, so can someone explain to me why lead was added to gasoline in the first place? Disregarding its toxicity, what benefit does lead buy you?

savrajsingh 3y ago
Allows higher compression of the fuel before it combusts. watch this: https://www.youtube.com/watch?v=IV3dnLzthDA https://www.youtube.com/watch?v=IV3dnLzthDA
loeg 3y ago
https://en.wikipedia.org/wiki/Tetraethyllead https://en.wikipedia.org/wiki/Tetraethyllead > It is a fuel additive, first being mixed with gasoline beginning in the 1920s as a patented octane rating booster that allowed engine compression to be raised substantially. This in turn increased vehicle performance and fuel economy.
amarshall 3y ago
Increases octane rating, that being is necessary to prevent engine knocking at higher engine compression ratios.
- lawlessone 3y ago
  So higher octane means it needs higher temp/ pressure to burn? I've completely misunderstood octane my whole life.. i always thought it meant "high octane make engine brrrrrr fast"
  - bombcar 3y ago
    Higher octane allows it to get compressed more before it goes boom, which means you can make a more powerful engine. But adding high-octane gas to a normal engine doesn't make it go any more boom, in fact, it goes less boom because it doesn't burn as much when it booms. Modern engines can be designed to advance or retard timing based on knock, so they can run on different octanes and provide different power curves.

dlandis 3y ago

Could someone please summarize what the expected timeframe would be? How long until leaded avgas is not used?

civilitty 3y ago
It’ll probably take another 10-20 years to outright ban it. Though the EPA might make it illegal to manufacture any engines that use leaded gas far sooner than that. Now that there is an unleaded alternative, older planes will slowly replace their engines at the next engine rebuild. There is a grave pilot shortage already and the FAA loathes to make GA even more inaccessible than it already is so it’ll be a slow process.
- pc86 3y ago
  > older planes will slowly replace their engines at the next engine rebuild An alternative exists, but the FAA needs to certify it for each aircraft type. The majority of aircraft types are not certified for this. No A&P is going to do this because the plane won't be legal to fly in most cases. And at the risk of editorializing, I've never seen the FAA do anything with the goal to making GA more accessible, at least not intentionally.
  - phkahler 3y ago
    >> An alternative exists, but the FAA needs to certify it for each aircraft type. They have. It's done. nobody needs to worry about liability for switching. Availability will be a short-term problem, and banning leaded fuel will get it fixed quickly. https://www.g100ul.com/ https://www.g100ul.com/
    - lazide 3y ago
      They were talking about changing out engines for the planes, not the fuel.
      - phkahler 3y ago

londons_explore 3y ago

How many IQ points did the nation lose because of this delay?

AlgorithmicTime 3y ago
[dead]
JWoolfenden 3y ago
so many i can't count...
hotnfresh 3y ago
In general? Probably not measurable. In neighborhoods or cities that happen to sit under take-off or approach paths for, or downwind of, very-busy airports that see a lot of prop plane traffic? Maybe a measurable amount.
- russdill 3y ago
  I'm be most concerned about people that deal directly with the fuel and infrastructure.
  - londons_explore 3y ago
    I'm concerned about everyone. When you start getting lead into corn and wheat, it gets into flour and bread and pasta, and before long, everyone has eaten some. Sure - some have eaten more, and others less. But everyone has been impacted. Half of the US population has blood lead levels above the CDC 'safe' level.
    - fsckboy 3y ago
      > Half of the US population has blood lead levels above the CDC 'safe' level. That's a bogus statistic. I went to look up what you could be talking about, and it appears to be pretty shoddy alarmism, not on your part but poorly or shadily written reports. (disclaimer/reassurance: Lead is bad for us, and heavy metal exposures are cumulative over a lifetime, so the lower the better, and we should keep lowering.) But what you quoted implies that we are not succeeding quickly enough, and from things I looked at, that is not a conclusion that can be drawn. I didn't spend a lot of time on it, but just from a few headlines and an abstract, it's clear that the lead levels under consideration have been lowered recently (and for what I'm about to say, undoubtedly previously lowered other times), and are not toxicity levels but more like "hey, there's lead in this neighborhood". And the lead exposures they are talking about are "retroactively" encompassing the elderly who were exposed as children before the new levels (and unleaded gas) were a thing. So, they're saying "Among the entire population, half of people have previously received during childhood lead exposures when we didn't have current standards that we would now consider to be, not even unsafe, but where geographically we should focus our attention looking at the sources." --- sources: https://www.cdc.gov/nceh/lead/news/cdc-updates-blood-lead-reference-value.html https://www.cdc.gov/nceh/lead/news/cdc-updates-blood-lead-re... 2021, CDC updated the blood lead reference value (BLRV) from 5.0 μg/dL to 3.5 μg/dL. A BLRV is intended to identify children with higher levels of lead in their blood compared with levels in most children... It is not a health-based standard or a toxicity threshold... should be used as a guide to 1) help determine whether medical or environmental follow-up are recommended and 2) prioritize communities with the most need for primary prevention of exposure. .. BLRV is a population-based measurement that now indicates that 2.5% of U.S. children aged 1–5 years have BLLs at or above 3.5 μg/dL. https://pubmed.ncbi.nlm.nih.gov/35254913/ https://pubmed.ncbi.nlm.nih.gov/35254913/ Considerable effort is expended to protect today's children from lead exposure, but there is little evidence on the harms past lead exposures continue to hold for yesterday's children, who are victims of what we term legacy lead exposures. We estimate that over 170 million Americans alive today were exposed to high-lead levels in early childhood, several million of whom were exposed to five-plus times the current reference level [which is not a health or toxicity level]. Our estimates allow future work to plan for the health needs of these Americans and to inform estimation of the true contributions of lead exposure to population health. We estimate population-level effects on IQ loss and find that lead is responsible for the loss of 824,097,690 IQ points as of 2015. ...and you can't add IQ points like that, most especially if you are part of the substantial segment of the population that says that IQ is a bogus measurement, a segment that heavily overlaps with environmentalism.

lawlessone 3y ago

Damn. The chemtrails people were right. For all the wrong reasons.

nonsense123 3y ago
It's no accident. Spin doctors work in strange ways, but they do work.

w10-1 3y ago

It's complicated. Overall it's better to do most anything to protect kids' development, but doing so is tough. Leaded avgas mainly benefits turbines, which are a minority of GA planes but the majority of avgas users, because they're the always-running commercial subset. The benefit is in time between overhauls. Every replacement fuel has resulted in more engine deposits and more maintenance -- essentially requiring $20K overhauls at 1,500 hours instead of 3K. For non-turbine GA, typically age catches up to the engine before hours, but for commercial turbines it can be a make-or-break decision, since a company might own only one or two. Reid-Hillview airport in San Jose is an example of an airport closed over leaded fuel concerns, because they reportedly found an increase in lead in children's blood in a few who lived right next to the airport. That increase was minimal compared to elevated levels found in Oakland and elsewhere due to ingestion of 60+-year-old leaded paint, but it's essential to remove whatever sources there are. The EPA has often complained, but the FAA has persisted. This particular move is noise before the next election (timed for the just-approved FAA appointee). It's unclear if it will result in anything faster than the decades-delayed process already in play, but it does give communities huge leverage in their lawsuits. Local airports often have a lot of land being used for essentially nothing. When local communities take federal money to develop or maintain airports, they legally agree that the airport is to remain in near-perpetuity. It can take decades of refusing federal money to get out from those obligations. The redevelopment opportunity presented by closing an airport in San Jose or Santa Monica is in the billions of dollars. So there are strong economic interests supporting anything that turns a community against the local airport. And since few people want to have planes overhead, those neighborhoods are typically lower-income and often under-represented politically, raising environmental justice concerns and making for concealed politics as monied interests fund advocacy campaigns and scientific research. Commercial turbine operators, GA owners, and local businesses using general aviation typically have fixed assets that commit them to protecting the airport. The price of avgas runs 50-150% over automotive fuel. For refiners, it's a production shift and a run that lasts 1-2 weeks per year (and hence some storage costs as well). They also have fixed assets, though distribution networks have in some cases been outsourced in anticipation of moving in or out of the avgas market. They do it mostly to keep people happy, since it's not a big profit maker. A big issue is ethanol. It's seasonally mixed into automotive fuel almost everywhere, but it attacks most of the current fuel systems. With engine re-certification for avgas, there are only 1-3 manufacturers running a few engines through time on test beds and some pilot programs. That's much, much easier than retrofitting fuel systems of many, many models of planes. In most cases, the manufacturer is no longer in operation, or they would love to see the old planes die so they can sell new ones (often having bought minimal name and assets out of bankruptcy). Electric is unlikely to replace turbine ICE unless the energy density improves in ways that would transform the entire world. It's more likely smaller jet engines could replace them, but it's not clear who would do that engineering for a relatively small market. So a pessimistic prediction is that this might help some local land grabs, but is not likely to help a lot of kids. Let's hope for more than that.

leadtester 3y ago

[dead]

mattmaroon 3y ago

I’ve never met a group more resistant to change than GA enthusiasts. They think they have a God-given right to fly the same way they did in the 1940’s. I was getting into it right as the ADS-B rules were coming into play. It is a cheap and easy (by aviation standards anyway) technology designed to prevent mid air collisions, and you’d have thought the FAA was requiring them to murder their children.

stouset 3y ago
Hell, some pilots insist on continuing to fly without radios.
- salusinarduis 3y ago
  There's a strong overlap of these people also doing stupid stuff like flying near and on the final approach courses of instrument approaches.
deleted 3y ago
[deleted]
mattgrice 3y ago
change has only ever been bad for GA. GA is now just a really expensive sport for old people who bought their planes 40 years ago when Beechcraft ran ads in National Geographic. Of course they are going to be resistant to change, and possibly rightfully so because GA is 1 or 2 steps away from being completely dead.
- bradley13 3y ago
  No sympathy. Where I live, there are strong noise restrictions on holidays and Sundays. A huge proportion of the population support this - it is very nice to have days without lawnmowers, chainsaws or whatever. Who is exempt? Aviation. One plane makes noise over tens of thousands of people. The absolute worst are the stunt planes.
- ryandrake 3y ago

blahyawnblah 3y ago

Do aviation engines required hardened valve seats like automotive engines did for the changeover?

bluGill 3y ago
Maybe. Most automotive engines ran just fine for a normal lifespan without changing the valve seats. When you work the engine hard you need it, but if you are not racing you generally got by with it. Of course the change for automotive was the early 1980s when engines were not as reliable and didn't last as long. Don't forget that aviation engines are require a lot of regular rebuilds. In a car you wait until something breaks, in an airplane you replace parts long before they might fail to ensure it doesn't break when in the air. So for many we can just add replace the seats/valves in the next tear down and be okay.
jabl 3y ago
Practically all aviation engines have used hardened valve seats since even before WWII. Maybe some WWI era engines didn't have them, I'm not sure.

kortex 3y ago

Why are diesels so uncommon among piston aircraft, it's almost always avgas? Is it just "because that's how it's always been" or are there actual engineering reasons diesel are inferior? Cursory searching suggests it's mostly this inertia. It'd be especially useful if they could run on regular jet fuel, then turboprops/jets and pistons could use the same fuel infra.

russdill 3y ago
There's a number of difficult engineering tradeoffs. Engines that can run on diesel typically need to be heavier.
PumpkinSpice 3y ago
Diesel engines operate at higher pressures and must be considerably heavier to achieve the same performance & efficiency. Not a huge issue for ships, trains, or cars. Huge issue for flying stuff.
jacquesm 3y ago
Power to weight ratio. Diesel engines tend to be cast iron rather than aluminum.
jabl 3y ago
As others mentioned, diesels tend to have worse performance/weight due to heavier construction. In the early days of aviation (like 1930's or such) there was some effort to introduce diesels for long-range aircraft, the idea being that the heavier powerplant would be offset by the lower required fuel load due to better fuel economy. But they weren't successful. More recently there has been something of a renewed interest in aviation diesel engines, the motivation being they can run on Jet A-1 in addition to diesel fuel. Jet A-1 is what jet (and turboprop) aircraft use, and is available at basically every airport worldwide, is much cheaper than avgas, and no risk of being phased out like the leaded avgas being discussed in this article.
papa-whisky 3y ago
As the sibling comments have pointed out, power-to-weight is the main reason, but it doesn't make diesel engines completely unfeasible for light aircraft. Diamond Aircraft have had success selling planes with diesel engines recently, and even started a subsidiary company to manufacture them: https://en.wikipedia.org/wiki/Austro_Engine https://en.wikipedia.org/wiki/Austro_Engine

__MatrixMan__ 3y ago

Oh, this is fuel we're talking about. I was imagining lead somehow involved in lifting gas, like a leaded zeppelin or somesuch.

RecycledEle 3y ago

[flagged]

digitalsushi 3y ago
Would you consider elaborating upon this? I don't have a reason to doubt you, but I am also picturing the people who fly airplanes as being sympathetic to older machines. And I'm in that camp of unscientific people who figure a 23 old truck (specifically using unleaded fuel) that doesn't need to be rebuilt anew is actually kinder to the earth than the alternative.
- RecycledEle 3y ago
  I remember the legal precedent set during the trial of US President Bill Clinton. He claimed the law he was being sued under (sexual harassment) was unconstitutional, which it was. The problem was that he signed it into law, and not even The President can not be that big of a hypocrite in an American court room. So he lost. If someone is blatantly hypocritical, I have a great desire to hoist them with their own petard (to use their argument against them.) Since the people who fly the largest private planes openly demand I stop driving my old pickup, I make the much more moderate demand that their airplanes meet each and every single emissions and fuel economy requirement that my old pickup has had to meet to stay on the road all these years. I 100% support grounding all civilian air travel, world wide. I would give them the same time I would have if my old pickup failed an inspection to come up to standards, or their planes would be scrapped. Good luck to them getting catalytic converters on jet engines.
jlmorton 3y ago
No need to ban it, but I'm happy to support a carbon tax on aviation equivalent to the current market cost of CCS, so something like $200/t. So, for instance, Elon Musk's private jet is estimated to have emitted 2,112 tons in 2022. Elon would have to pay a $400,000 carbon tax. Ideally these taxes would flow through fuel, but that presents some challenges, since planes can re-fuel in jurisdictions without those taxes, although that's certainly harder to do in the United States. I think in the US, it might be hard enough to do that that just taxing the aviation fuel is fine.

ouiouibaguette 3y ago

I live near a lake that sees a lot of floatplane takeoffs. I wonder how many IQ points were lost among the rich folks with lakefront properties.

dadjoker 3y ago

Shorter EPA: "Look, here's one more way we can cripple our economy! Yea!"

skeaker 3y ago
If that's the only angle you care about, then consider that a population free of lead-induced brain damage provides a stronger economy in the long run as more of them are able to enter the workforce rather than prison [1] or a grave [2]. [1] https://en.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis https://en.wikipedia.org/wiki/Lead%E2%80%93crime_hypothesis [2] https://en.wikipedia.org/wiki/Lead_poisoning https://en.wikipedia.org/wiki/Lead_poisoning
elif123 3y ago
[flagged]

Robotbeat 3y ago

Good

bradley13 3y ago

Huh? Leaded fuel or recently produced engines? Honestly, that's shockng. Zero excuse, should have been outlawed decades ago.

deleted 3y ago
[deleted]

briandear 3y ago

Perhaps the FAA could remove the requirement to buy an STC to use unleaded fuel? If they want wider adoption, removing the STC requirement would help.

jabl 3y ago
I suspect what needs to happen is that someone (ASTM?) comes up with a spec for unleaded 100 octane avgas, and then the FAA can give a blanket approval for that spec for any plane certified for 100LL.
- sokoloff 3y ago
  Can't (realistically) be done. The specification for most airplane engines say "100LL" and the specification for 100LL is a composition specification (ASTM D 910), not a performance specification. If your fuel meets ASTM D 910, it contains lead. If it doesn't contain lead, it doesn't meet ASTM D 910 and therefore definitionally isn't 100LL, so if your engine type certificate data sheet calls for 100LL, it unavoidably calls for lead. If you are flying an aircraft that is thus-certified, flying it with a different fuel is, per the FAA definition in 14CFR3.5, flying an unairworthy airplane. "Airworthy means the aircraft conforms to its type design and is in a condition for safe operation." That's the legal reasoning that the Gami STC is required: to change the TCDS of the engine and airframe to permit a fuel other than 100LL and still be considered airworthy. (The STC process is totally workable and, IMO, doesn't need to be "fixed" and Gami has basically done the work you're asking to be done AFAICT.)
  - jabl 3y ago
    Weren't many of the planes in operation today certified before 100LL became the only available grade (excluding things like 115/145 or even more exotic brews which I guess today are used only at Reno air races and such)? E.g. 80/87 for lower performance engines, and 100/130 for higher performance ones. So presumably they were somehow grandfathered in when 100LL replaced these grades? So why can't the same be done for a hypothetical "100UL" spec?

DigiDigiorno 3y ago

The uphill battle of unleaded avgas leaves both the main players in the industry and the regulators themselves looking bad—but in a banal kinda way. I enjoy AVWeb on YT for AV news (really, I just enjoy the humor/personality of Paul Bertorelli lol), here are a few insightful videos that summarize the story: The Long, Twisted And Slightly Ridiculous Story of Avgas Part 1 (14:22) https://www.youtube.com/watch?v=9F-WngVMJBQ https://www.youtube.com/watch?v=9F-WngVMJBQ Part 2 (15:15) https://www.youtube.com/watch?v=Mvse4Xhzwuk https://www.youtube.com/watch?v=Mvse4Xhzwuk and G100UL Approved Now What? (When the FAA approved the first unleaded 100-octane avgas a year ago) https://www.youtube.com/watch?v=ibIkuyBL9i8 https://www.youtube.com/watch?v=ibIkuyBL9i8

donbatman 3y ago

Any aircraft mechanics care to comment on this? I know lots of small privately owned aircraft are really really old. Like 50s or 60s or older. Is this going to screw up their fuel system gaskets and seals?

oldbbsnickname 3y ago

TEL is incredibly bad stuff*, but it's rarely used in commercial flight operations as they predominantly use jet aircraft. Leaded avgas is completely unnecessary as non-TEL fuel formulations have been created and certified. The problem is they're not available anywhere, while leaded avgas is everywhere in GA. Municipalities should do like they did for leaded automotive gasoline: supersede commercial interests with public health regulatory ones and ban it. (The EPA only banned leaded automotive gasoline nationwide in 1996 after allowing 25 years for the phaseout.) * In the same category of human harm as nerve agents, dioxin, and methylmercury. https://www.aopa.org/news-and-media/all-news/2021/july/27/gami-receives-unleaded-avgas-stc https://www.aopa.org/news-and-media/all-news/2021/july/27/ga... https://www.epa.gov/archive/epa/aboutepa/epa-takes-final-step-phaseout-leaded-gasoline.html https://www.epa.gov/archive/epa/aboutepa/epa-takes-final-ste...

lazide 3y ago
The first general purpose non-TEL alternative was only certified last year. Before that, each variant had to be certified per-type, and then would need to be stocked everywhere. Which never was going to happen, and didn't. Now they're going to ban leaded avgas, which should force the for adoption, since there IS now an approved general purpose alternative.

archsurface 3y ago

"Finding that pollutions from aircraft engines contribute to air pollution".

trhway 3y ago

Waiting for the Tesla of the aviation as that lead vs. unleaded feel like something ancient. Lets look at numbers as of today: Cesna 172 - 75kw engine, on 50kw power makes 1000km as 200km/hr. Engine plus fuel weight 350kg. The engine costs $26K. Today's lithium batteries like ones used by Tesla is 280wh/kg. At retail similar batteries cost $400/kwh. So, we can have 75kw electric engine and 100kwh battery at the same weight as ICE engine plus fuel on Cesna 172 and at a retail cost of $50K and have 2 hr flight of 400km. That isn't a worse starting point than what Tesla had 15 years ago against ICE cars.

lazide 3y ago
Now add several thousand lbs of paperwork, and some absolutely insane liability court precedent [https://www.ainonline.com/aviation-news/2007-11-27/cessna-found-liable-480m-crash-185 https://www.ainonline.com/aviation-news/2007-11-27/cessna-fo...], and you'll see why it hasn't happened yet.