AOPA is warning aircraft owners who normally use automotive fuel purchased off the airport to test the gas for ethanol even if the pump doesn't say there's alcohol in the fuel. The federal government mandate to increase the use of renewable fuels in gasoline blends has prompted some companies to add ethanol without notification and that can be dangerous for aircraft engines. "While AOPA has successfully prevented ethanol from being blended with avgas, there are limits to what the general aviation industry can do to prevent auto gasoline from being blended," AOPA said on its Web site In Idaho, pure gasoline is apparently so rare that it's no longer available at some airports. "What I'm hearing from my members is that they cannot find ethanol-free auto gas on airports anywhere," Idaho Aviation Aviation Association Director Ken Jackson said in an email to AVweb. "Their choices now are to switch to 100LL, run contaminated fuel, or hang it up."
The FAA forbids the use of ethanol-blended fuel in regular aircraft. Ethanol-blended fuel can harm rubber fuel bladders, damage hoses, and attract water into the engine encouraging rust. FAA studies have also shown ethanol to cause inaccurate readings on fuel gauges and problems with electric fuel pumps. Premium auto gas in some states has been saved from an ethanol mix too, but that may change due to mandates put on the petroleum companies. Avgas is not suited to many older engines because of its high octane. The salvation for pilots who want or need to use mogas could come from the recreational motorsports sector, which may have the numerical clout to make regulators listen. Many engines used in boats, personal watercraft, ATVs and motorcycles are also harmed by ethanol.