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Comment by jwess | Hacker News Reader

It's scary to think that the transition to unleaded aviation fuel, or avgas, only began a couple years ago, and is scheduled for 2018 [0].

Currently, Avgas, which is different than jet fuel in that it's mainly used by private single-engine planes (ICE instead of turbine), can still contain up to 2.12 grams of lead per gallon [1]. Surprisingly, this 2.12 grams of lead/gal is termed 100LL, for 100-octane "low-lead". Up until the 1970's avgas could contain up to 4 grams of lead per gallon.

I believe that lead exposure caused by the widespread use of avgas is a serious public health concern. Unfortunately most private plane owners are strongly against it due to the higher price of unleaded fuel. I really hope that the EPA succeeds in meeting their deadline.

[0] http://www.faa.gov/about/initiatives/avgas/ [1] http://www.gpo.gov/fdsys/pkg/FR-2010-04-28/html/2010-9603.ht...

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The article says that lead in aviation fuels (and in solder) is a far smaller contribution to current lead levels than remaining lead paint. In the grand scheme of things, there just isn't that much avgas used, and it gets dispersed widely as opposed to concentrated where people live.

I think the real problem is the big aviation piston engine companies (e.g. Lycoming and Continental) that seem to have no incentive to develop modern engines that can run on unleaded fuel. Newer engine manufacturers (e.g. Rotax, Jabiru) run fine on auto fuel, but they have a much smaller market. (It's sort of ironic that users of those engines, who should not be run on leaded gas, have a hard time finding unleaded gas at airports in the US.)

IMO, the FAA and their standardization processes for fuels like G100UL (GAMI), UL102 (Swift) and 91/96UL (Hjelmco) is the bottleneck here. GAMI in particular appears to have a fuel ready to use (in lab/prototype quantities) and has flown test flights in normally aspirated and turbocharged applications. (Turbos live a harder life, have lower detonation margins and are generally a more difficult test case. Many normally aspirated engines would run fine on ethanol-free pump gas from the corner service station.)

I don't necessarily fault the individual FAA employees; they have every incentive to make GAMI, Swift et al jump through hoops to prove that their fuel is as safe and has as high detonation margins, even in worst case, high, hot and heavy departure conditions, as the proven over many decades 100LL fuel. It's a "heads I lose", "tails we push" set of incentives for them, so I don't blame them for being reluctant to move swiftly.

I feel bad burning 100LL in an engine (from Continental) perfectly capable of (and even happier) running on ethanol-free 87 octane pump gas. I'd happily buy clean mogas instead of low-lead, but it's virtually impossible to find and low-lead is available at the overwhelming majority of airports.

Yet another advantage for aviation diesels (like the Thielert, Delta Hawk, etc.), largely developed due to the military drone program. They can run on Jet-A/JP8/diesel, and getting clean diesel is a whole lot easier than clean gasoline.

Automotive race fuels are leaded as well. I'm not sure what the regulations on them are.

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