7 votes

FAA approves unleaded aviation gas covering piston fleet

6 comments

  1. [5]
    GnomeChompski
    Link
    I've found it so difficult accepting that we haven't yet forced the transition off of leaded aviation fuel. I expect others do too and this approval makes it feel like a huge step in the right...

    I've found it so difficult accepting that we haven't yet forced the transition off of leaded aviation fuel. I expect others do too and this approval makes it feel like a huge step in the right direction when it is in fact just inching along.

    2 votes
    1. [4]
      skybrian
      Link Parent
      It's general aviation, so yeah, it's not moving too quickly. Airplanes are expensive and maintained for many decades. And aviation is highly regulated, so regulatory changes are a big deal, even...

      It's general aviation, so yeah, it's not moving too quickly. Airplanes are expensive and maintained for many decades. And aviation is highly regulated, so regulatory changes are a big deal, even if the physical changes aren't.

      I wonder if any physical changes are needed to older aircraft?

      6 votes
      1. [3]
        GnomeChompski
        Link Parent
        This is really a regulatory issue rooted in lack of legislative will combined with red tape between the FAA and EPA. Lower octane unleaded Avgas of 94 octane has been developed and approved for...

        This is really a regulatory issue rooted in lack of legislative will combined with red tape between the FAA and EPA. Lower octane unleaded Avgas of 94 octane has been developed and approved for many years now and could have been mandated long before that.

        Also, this new unleaded formula will be a one-for-one change with no need to alter any legacy aviation piston engines. The change in formula simply creates an alternate path to gain the same results of high compression stability or a target anti-detonation factor (octane level).

        High performance ICEs need higher octane because lower octane fuel can combust too soon under their high compression which can cause timing issues and even damage cylinders, valves, etc... This is why diesel engines don't need spark plugs, they ignite the fuel through compression. Diesel fuel has an average octane rating of about 30 AKI.

        I know jet fuel doesn't contain lead for added octane, but piston driven engine fuel still does due to the fuel not being regulated and not due to lack of innovation or the aircraft manufacturing industry and their ability to change. Even if it were a manufacturing issue, the auto industry moved at a snail's pace over the last 5 decades to become more efficient due to CAFE mandates, but they switched over almost immediately from leaded to unleaded.

        The silent problem that isn't being discussed.

        The 131-page report detail's the findings of 17,000 blood samples collected from 2011-2020 from children under 18 years of age living near the airport. It found that children living downwind from the airport had higher blood lead levels than those living upwind, with increases of .4 micrograms per deciliter.

        In comparison, lead levels during the Flint water crisis were between .35 to .45 micrograms per deciliter over the baseline.

        4 votes
        1. [2]
          skybrian
          Link Parent
          Most of the aviation industry moved to jet fuel, which is close to kerosene. Even the aircraft you see with propellers is mostly jet fuel. As a result, the piston-driven aircraft used by general...

          Most of the aviation industry moved to jet fuel, which is close to kerosene. Even the aircraft you see with propellers is mostly jet fuel.

          As a result, the piston-driven aircraft used by general aviation are a fairly small niche, economically speaking.

          1 vote
          1. GnomeChompski
            Link Parent
            So I'm not sure what the share of leaded vs unleaded fuel is for piston driven (propeller) airplanes around the world (although I'd love to see some stats), but the crux of all of this is really...

            So I'm not sure what the share of leaded vs unleaded fuel is for piston driven (propeller) airplanes around the world (although I'd love to see some stats), but the crux of all of this is really the fact that leaded fuel still exists in the face of how toxic it is for neurological development. And that is the real near and dear issue for me. There simply is no reason to allow leaded fuel, at least not in leading nations that can afford the slight cost increase.

            Simply put, we should not put an economic savings "price tag" above serious heath issues like brain development... Even if it is only a small part of aviation and a small portion of the population that live near an airport that have to deal with the problem.

            2 votes
  2. skybrian
    Link
    From the article: [...] [...]

    From the article:

    In 2021 the FAA approved STCs [supplemental type certificates] for GAMI covering a smaller number of Cessna 172 engines and airframes, and then expanded the approved model lists to include essentially all lower-compression engine and airframe combinations. Though that was seen as an encouraging step forward in the years-long path to supply unleaded aviation fuel to the piston aircraft fleet, the STCs did not include aircraft needing the higher-octane fuel that accounts for 60 to 70 percent of avgas consumption. This latest announcement by the FAA addresses the needs of those higher-compression engines.

    [...]

    The timing for when G100UL will reach airports is still uncertain. “It’s going to take a while to manage the infrastructure” including manufacturing and distribution, Braly said. The supply chain “is still a very wounded infrastructure and that’s not going to make the process any easier, but we have a handle on how to do this, and with the support of the major players I think we can do that. It’s going to be limited to begin with, but it can be ramped up rapidly,” he said.

    Baker said it’s important to get any fuels approved for use to the California market as soon as practical, in light of the fact that some municipalities have prematurely banned the sale of leaded avgas and threatened a safe and smart transition to unleaded fuel. “It is a politically charged issue there, and this will help keep our airports open with fuel that works with all aircraft.”

    [...]

    While the cost of the fuel has not been determined, Braly said the small-batch production process that will initially earmark the arrival of G100UL at airports means that the fuel will cost slightly more than leaded avgas. “Small volume batches cost money,” he said. “Until we can get [production] revved up that we’re making millions of gallons at a time, there will be an incremental [additional] cost,” he said.

    “It’s not going to be unreasonable,” he said. “Pilots in America will not be paying what they’re paying for avgas in Europe today.”