Recently, reader Frank Klein asked if he should be concerned about filling up containers of auto gas for his plane if the previous customer pumped 10% ethanol fuel from a pump island that uses a common dispensing hose for several grades of auto gas.
When I do some rough calculations, I figure that the amount of fuel contained in the hose and meter would give you close to a gallon of fuel, so if you are using a five-gallon container, you would have close to 20% ethanol-containing fuel.
I remember when I received auto gas for my farm that had been contaminated with 20% ethanol-containing fuel. It shut down every gas tractor I used it in, plus the lawn tractor and a small pickup. So yes, that amount of ethanol could cause a problem in your aircraft.
So what should a pilot do when buying fuel?
First, if it is a common-dispensing hose pump, add at least four gallons of fuel to your vehicle or other container before putting any fuel into the containers you plan to use in your plane. The second step is to always take a sample of the fuel and test it for ethanol before you ever get it near your plane.
Another reader, Ray Neal, asked what he should do when he goes south for the winter, not just about his plane, but other non-aviation equipment he stores in his hangar.
This is a major concern for pilots who use auto fuel in their aircraft. If they do not carefully check their fuel for ethanol, they can have very serious damage to their fuel system if they let it sit over the winter for several months. The problem is the fuel will expand and contract with the change in temperature from day to night. This forms moisture, which will mix with the ethanol and lead to corrosion.
So what to do? Again, I cannot stress enough the importance for pilots to always check every fuel purchase for ethanol.
Another suggestion for pilots who let their planes sit for extended periods: Run the fuel level down fairly low and then fill it with 100LL, which has much better storage stability than auto fuel — and you can be sure it does not contain any ethanol. You can also use 100LL in older tractors and yard equipment. Check your manufacturer’s recommendations.
Mr. Neal pointed out another problem: Disposing of ethanol-containing fuel. For example, if you have fuel with ethanol in your lawn mower and do not plan on using it for six months, you should drain it out and add fresh non-ethanol fuel. But what do you do with the fuel drained out? If you have a late-model gasoline-powered vehicle, you can put it in there. However, most recycle places will not take it because it causes problems in their systems.
Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985. You can contact him at Visser@GeneralAviationNews.com.
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