Unsafe Lead Levels in Tap Water Not Limited to Flint

The total US lead emission from general aviation is about 500 tons per year, which in 2002 was about 45% of total lead emissions (which is higher than I'd thought). One caveat is that is an upper-bound number, not all 100LL fuel has the maximum quantity of lead additive. It's fine if it reaches 100 octane on a smaller amount. It's also a historic number: the industry is shifting towards 100 Very Low Lead type with a 20% lower TEL limit. And general aviation has been in decline for about two decades due to spiralling cost. So that number is probably on the high side.

Most of the fleet (~70%) would be OK switching to 94-octane unleaded. The biggest problem is that Congress/states have made it extremely difficult to source this type of fuel, because the overwhelming majority of fuel is produced for automotive usage. Ethanol and other mandated additive blends are unacceptable for aviation usage, and we're talking about 0.1% of the fuel market. Congress/states have put up barriers that impede a shift and they need to do something to help that overcome those barriers, not just ban 100LL.

Also, due to the nature of general aviation this is a very distributed problem. Most general aviation occurs at relatively small airfields/airstrips and there's many factors that make it difficult for GA pilots to use large airports (limited access to those airspace types, high traffic levels from commercial aviation, high ramp/fuel fees designed to discourage refueling, etc). So you've got to get 92UL available at a large number of small sites. Most small airports will carry at most two types of fuel, 100LL and Jet A1, and many will only carry 100LL. Most airports are running on super thin margins and adding 92UL would mean not carrying 100LL.

That leaves the 30% of aircraft that can't use 92UL pretty high-and-dry. Some can be modified, some will need engine replacements, a lot will be out of luck. Unfortunately they are likely concentrated at the affordable end of the fleet, and that translates into more cost increases in a sector that's already dying due to a cost spiral.

General aviation is a feeder for commercial aviation, and that's going to become an even tougher and more expensive path to follow. Going commercial requires a large number of flight hours which are typically accrued by getting an instructor license and training casual pilots - so cost increases that reduce casual pilot time percolate very directly into a reduced supply of commercial-eligible pilots. The only other route is ex-military pilots, or paying >$100k through a university (which is not commercially viable due to the ~$20k average salary of an entry-level regional pilot).

General aviation is also a neat cultural touchstone that I am sad to see shrivelling into nothing :(

Interesting, have to check if the library has a translation of this available.

He was also chosen to tour and report on post-Second World War Germany due to his experience from similar humanitarian missions he undertook in Europe in the aftermath of the First World War.

Does anyone think that it's possible that there will be another career engineer as POTUS? I've heard that there remains a sort of stigma to such a thing, perhaps in part due to the Hoover administration.

Most (>95% for sure) small planes use leaded fuels. Many (probably three-quarters of the fleet, but probably less than a quarter of the gallons of avgas burned) of those planes could readily use ethanol-free unleaded avgas without significant modification.

The high powered planes are the ones that also fly the most hours and burn the most per hour, which is why the bias is so different by gallons rather than fleet size. Many of those perform critical functions (mail/parcel delivery, food delivery, remote people transport, pipeline patrol, traffic reporting, pilot training) and there is no certified replacement fuel available. The logistics are such that if an airport business has to carry leaded fuel for 75% of your avgas sales and the other 25% can also burn 100LL, there's little incentive to install duplicate tanks, fuel trucks, etc for zero additional sales of fuel.

There are promising unleaded fuels in testing (not derived from unleaded autogas) that the high-compression and turbo-charged aircraft can run without modification. The approval process via the FAA is very slow-moving, expensive, and risk-averse. (in many cases for very good reason, but it's still a significant barrier in that I cannot legally burn the prototype fuels, nor any unleaded fuels, in my aircraft).

I would switch to the GAMI fuel tomorrow if it was available for sale. For the small amount I burn per year (estimated 1500-2000 gallons), even an increase of $2/gallon would be no barrier for my adoption and the likely increase vs today is lower than that. There are other fuels also under consideration or certification testing, some of which require airframe or engine modifications, others of which are also "drop-in" replacements.

TEL really is fairly magical in terms of improving knock and detonation margins in highly stressed engines, so it's no surprise that its adoption became so widespread after World War II. The transition away from TEL is not a trivial exercise, which is why it's "taking so long" to make progress on this. The world needs a physically and chemically workable fuel, but also needs an economically workable fuel.

Go to your local aquarium/tropical fish dealer and ask. They'll be able to list pretty much all the providers within a reasonable driving range.

Also lots of cities/towns have RO water providers that will sell anywhere from single gallons to thousands.

source: used to be a marine aquarium hobbyist and bought thousands of gallons of RO water to make seawater.