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 testing and development costs. Where are we almost 30 years later? Basically, in the same place, with a government funded study telling us we are in the same place.
Why could the industry develop leaded avgas in a few short years during World War II and not do the same for an unleaded fuel utilizing all of the knowledge gained over the last 70-plus years?
During the war effort, most of the people at the Shell lab were working on the project and we had a large number of combustion scientists. Now we have scientists working on producing more fuel at a lower cost.
The same is true for the engine manufacturers who do not have engineers working on new engine designs, but rather working on keeping 70- to 80-year-old engine designs working.
Another sticking point is social media and the Internet. There is a lot of misinformation or non-substantiated information online. For example, several years ago, I attended EAA AirVenture Oshkosh and asked most of the knowledgeable engine people if they had noted any exhaust valve recession cases for people who were using just unleaded mogas from the start. All of them had examples of recession on new or just overhauled engines.
I wrote this up in a column and got a great deal of negative feedback. Most of the comments came from people who had “read on the Internet” that someone somewhere had gone to full TBO using only unleaded fuel.
But the problem isn’t social media. The problem is we are still using 70- or 80-year-old engines that were designed for — and only possible because of — high octane leaded fuels.
In the automotive world, all of the engines have been redesigned to run on unleaded fuel because of catalytic converters. Modern cars have liquid cooling, knock sensors, electronic fuel injection, and on and on. When is the last time you saw a carburetor equipped air-cooled car roll off the assembly line in the USA?
So what’s next?
One possibility is a plan suggested 30 years ago of promoting a 94ish unleaded fuel, while continuing to produce 100LL. Another option is to introduce a 100UL fuel that does not meet the requirements of many aircraft in the general aviation fleet and let the planes fall where they may. (Have I mentioned the liability problems with a new fuel?).
Or we can continue the current process and have another study released in another 30 years and see how much progress has been made.