There is still a lot of confusion about the transition to a new unleaded avgas, especially around the differences between fuels approved through the Supplemental Type Certificate (STC) and a specification from the American Society for Testing and Materials (ASTM). It may help to look at the history of specifications for avgas.
Aviation Fuel
Aromatics may be cause of valve seat recession after using unleaded fuel
Testing by Lycoming Engines has “demonstrated that, under certain conditions, use of UL94 may impact valve seat recession.”
Murphy’s Law and the search for an unleaded fuel for general aviation
Murphy’s Law states that anything that can go wrong will go wrong. In the transition to unleaded fuel for general aviation, what could possibly go wrong?
KLGB launches unleaded fuel subsidy program
The FAA has set a target for the elimination of leaded aviation fuel for all piston-powered aircraft by the year 2030. In an effort to speed up the transition at the local level, KLGB’s Unleaded Aviation Fuel Subsidy Program is designed to eliminate the cost difference between leaded avgas and unleaded avgas.
STC vs ASTM: What’s best for unleaded fuels?
There is some confusion as to how the ASTM process compares to Supplemental Type Certificate (STC) approval for the unleaded fuels that will replace 100LL. Some people even think that they are basically the same. In reality they are very different and most of that difference goes back to our old friend liability.
Another milestone towards an unleaded fuel for general aviation
The FAA has given the nod to UL100E, the unleaded aviation field for piston-engine aircraft developed by LyondellBasell Industries/VP Racing, to advance to full-scale engine and flight testing.
Are two grades of fuel needed in the quest for unleaded avgas?
The most common suggestion I have received concerning the future of unleaded avgas is that there is a need for two grades of fuels, not just one.
AOPA president flies on new unleaded fuel
AOPA President Mark Baker flew the Baron for one hour with G100UL feeding the left engine and 100LL in the right. He said the performance of the two engines was nearly identical and “the Baron flew beautifully.”
EPA grant to help disadvantaged communities transition to unleaded avgas
The U.S. Environmental Protection Agency (EPA) has given a $776,636 grant to the California Department of Public Health that will “provide technical assistance to general aviation airports in California in disadvantaged communities to support the transition from leaded aviation gasoline (avgas) to unleaded avgas.”