A powered parachute pilot experienced an engine failure and forced landing when his engine suffered fuel starvation due to the fiberglass fuel tank decomposing; perhaps because of ethanol in the auto gas used.

Narrative

Was flying a powered parachute in the wide open deserts. Engine starved for gas and died. I landed safely on a dry lake bed. As I was coasting to a stop; I let my foot touch the ground and broke my leg. The cause has now been traced to the fiberglass gas tank. It was coming apart inside; maybe due to the ethanol in the automotive pump gas. The outlet on the tank had a fine screen 'finger' filter that extended into the tank an inch or so. I had drained out old gas and put in new just before flying. When I dumped in the 10 gallons of gas; it stirred up the debris in the bottom of the tank. Some of it stays in suspension for a long time but eventually settles to the bottom. I flew for about 10 minutes before the engine died. This is my fault; I did not know that the fine screen was in the tank; I always check the in-line filter watching for stuff that should not be there but the screen in the tank caught everything so I didn't know there was a problem in the making. I had always fueled up after flying and anything stirred up settled to the bottom again before I flew the next time. I am installing an aluminum tank now. I am making this report in the hope that others with fiberglass tanks will check their tanks very carefully. I don't think this is manufacturer specific but all fiberglass tanks need to be checked if they are using automatic pump gas.