AOPA is working to amend a bill in the Washington state legislature (ESHB 2738/ESSB 6508) that would require all gasoline sold in the state contain at least 2 percent denatured ethanol. The problem with the bill is that there is no exemption for auto gas sold for use in aircraft.
"Many owners of older aircraft obtain supplemental type certificates (STCs) permitting the use of auto gas," said Owen Sweeney, AOPA manager of state and local government affairs. "Because of safety issues, the STCs prohibit the use of ethanol-blended gasoline. We're working with the legislature to amend the bill so that Washington pilots would still be able to obtain high-octane auto gas without alcohol added."
Auto fuel STCs were not developed considering ethanol-blended auto fuel, and its effects on components used in aircraft fuel systems, including fuel bladders, have not been determined. Moreover, ethanol in auto fuel attracts water, which has the potential to negatively impact aircraft engine operations. Alcohol (ethanol is grain alcohol) also has a lower BTU content, meaning the engine produces less power per gallon of fuel. That decreases aircraft range.
AOPA and others in the aviation community have been working in other states that have adopted ethanol requirements ( Montana) or are considering them ( Idaho and Missouri) to ensure that non-blended gasoline is available for pilots.
Updated: March 13, 2006, 4:54 p.m. EST