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this post was submitted on 14 Oct 2023
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United States | News & Politics
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Ultimately, bureaucracy.
The aviation industry is second only to nuclear in regulatory conservatism. They grind through change slowly, methodically, and expensively.
Every engine manufacturer went through a lengthy certification process to get their engines approved to run on avgas. If you want to burn a slightly different kind of fuel, you either need to go through that entire process again, or you have to convince the FAA that there is so little difference in the new fuel that it will perform identically in every engine that has ever been certified on the old fuel.
They finally achieved that second one earlier this year, after decades of work.
This makes the most sense by far. I think it has a lot to do with we just don’t put the money towards research and development we did in the 40’s and 50’s. Sure we still R&D but no one is dreaming up completely new ideas from the ground up and getting funding.
The most promising short-term approach is switching from spark ignition to compression ignition: Jet fuel is very comparable to diesel fuel, and doesn't have the same problems with lead that avgas has. It has a higher energy density, providing lower fuel burn and longer range. And it is significantly cheaper than 100LL, let alone 100UL.
Europe has a significant number of diesel-engined general aviation aircraft burning Jet-A. Several manufacturers have received supplementary type certificates to swap out gasoline engines for diesel in many of the most popular GA aircraft.
Longer term, electric and hydrogen are being researched, but it will be a long time before they are viable options in the GA fleet.
You're forgetting the easy third option. Just ground everything that requires leaded fuel. Problem solved.
Not really an option when pretty much every flight school in the world uses them, and we already have a shortage of qualified pilots.
We already have an excess of flights. Just reduce the amount of unnecessary flying.