It may be helpful to ask why. Why might aviation engines still be using leaded gasoline? If one knew why avgas was still leaded, that might point to possible pr

It may be helpful to ask why. Why might aviation engines still be using leaded gasoline? If one knew why avgas was still leaded, that might point to possible practical, implementable solutions. Yes, laziness, ignorance, stupidity, incompetence, malice, etc, are all possibly valid answers to "Why?". But accepting such answers without scrutiny when another answer may be closer to the truth is a bad habit, IMO. If you were to come into a legacy codebase at work and assume that the previous authors incompetent idiots, you'd probably be less productive than if you assumed that the previous authors had problems to solve and chose the best option available to them given the constraints at the time. Keeping in mind past and current goals, and past and current constraints is probably going to get you further than, "This is bad! Change it!"