Still no answer on unleaded avgas 30 years on

A new study from the National Academies of Sciences, Engineering, and Medicine on getting the lead out of general aviation fuel gave me a sense of deja vu.

Sponsored by the U.S. Dept. of Transportation, the study found that getting rid of lead in avgas was going to be difficult and maybe we should push an unleaded 94 octane fuel along with the 100LL now on the market.

The push for unleaded avgas started in the 1980s with the issuing of STCs for mogas by the Experimental Aircraft Association (EAA) and Petersen Aviation. This was more for cost and reduced spark plug fouling in 80/87 engines. 

Then in the early 1990s, there was a call for the removal of lead from all avgas because of environmental concerns. During that time, I met with engine manufacturers, engine rebuilders, and many officials from many organizations like the FAA, EAA, ASTM, etc.

The prevailing opinion of the real experts was that an unleaded avgas that would meet the anti-knock performance equal to 100LL was not possible at that time using the known technology — and certainly not at a reasonable price.

There were also safety and performance concerns like exhaust valve recession that needed to be addressed.

But the FAA, Environmental Protection Agency, and a bunch of other industry “leaders” formed a committee to develop a 100 lean rating avgas. 

Having a single dimension goal like a 100 lean rating is like a professional football coach who observes that most successful offensive lineman weigh over 300 pounds. So, he figures that any man who weighs over 300 pounds should be a good lineman. Unfortunately, it does not work that way.

This whole process was further derailed by Swift Fuels announcing it had an unleaded fuel that would out-perform 100LL and cost less to produce.  A fuel never materialized that came close to meeting the claimed performance.

But the committee pushed on with a number of other candidates and millions of dollars in

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