For as long as I can remember we have had Avgas in one form or another to power our piston powered aircraft. Avgas is a high octane aviation fuel generally identified by 2 numbers: the octane rating of the fuel tested to aviation lean standard and the octane rating of the fuel tested to the aviation rich standard. The U.S. government's insistence that 100 low lead be phased out has been identified as one of the most pressing issues for general aviation today. The issue is confusing to most of us in aviation because as far back as 1991 a Swedish company called Hjelmco Oil developed an unleaded Avgas 91/96 UL which met the leaded 91/98 standards except for the color of the fuel. Rotax, Lycoming and Continental have all cleared this fuel to be used in their engines, which means more than 90% of the world's fleet of piston aircraft could use the fuel. It has been produced in Sweden for almost 20 years, used in thousands of aircraft and flown millions of miles. My question is why this isn't considered a solution? What is the problem? In the meantime Continental is looking at diesel engines to replace their engines on existing aircraft, but that seems to be a very expensive solution to me. They are also testing another fuel, 94UL, and will not complete the testing process for about 3 more years. In February of this year General Aviation Modifications announced they were developing G100UL which is made by blending existing refinery products resulting in a fuel slightly more dense than 100LL, but which has a higher thermodynamic output. It is anticipated that the cost of this fuel will be at least as high as current 100LL fuel. With all of the piston powered aircraft still flying today a consensus solution needs to be found and implemented while we still have time. If everyone waits too long and the government bans 100LL there will be a lot of airplanes sitting on the ground unable to fly. What do you think? Until next time keep your wings straight and level Hersch! JetAviator7 Any one who has common-sense and patience may learn to fly. In the aviation schools a good working knowledge of airmanship is ordinarily gained in a total of four hundred minutes spent in the air, divided into a score of lessons. The air would almost seem the natural element of man, such has been the progress in flying during the past few years. — Francis A. Collins, first lines of the book 'The Air Man His Conquest In Peace And War,' 1917. ps: Don't forget to sign up for our newsletter "All Things Aviation" here!