Continental has reengineered its 100 hp O-200 engine with a fadec (full authority digital engine control) option and a 25-pound weight reduction for the light sport market, as one step toward accommodating unleaded fuel. Continental President Rhett Ross pointed out that even with engines that can burn unleaded gas, automotive fuel, as it is distributed today, is not an option for aircraft use. Additives such as ethanol are incompatible with aircraft engines, and there is not enough control on what additives are present in each batch of auto fuel. "There needs to be an aviation spec [for unleaded fuel]," he said. For its part, Continental is pushing the fadec issue, and there will soon be three engines with the feature available -- the O-240 and the IO-550 already have fadec; and a fadec-equipped version of the turbocharged IO-550 is on the drawing board. Meanwhile, Lycoming announced at AirVenture it now has three new engines in the works: the IO-233-LSA, a variant of its legacy O-235 series aimed at the light-sport movement; the 210 hp IO-390-A1A6, a certified version of the IO-390-X that has been used in the experimental-aircraft market and is a growth version of the IO-360 series; and the previously announced TIO-360-EXP, a noncertified turbonormalized, intercooled, fuel-injected engine that lays the groundwork for use of alternative fuels in Lycoming aero engines.