Roger, I know three pilots who owned retractable gear airplanes. All three had several hundred hours in those planes, but all three managed to put them on the ground with the gear up. In two of the cases, the gear warning horn was sounding the alert as they settled to earth. How could they be so stupid? All three said that something had happened to distract them during the approach, and they simply forgot to put the gear down. A distracted pilot could just as easily move the fuel selector to the wrong position, especially if he/she was familiar enough with the location of the valve that they reach for it without actually looking for it. It is often not the young pilot new to the plane that makes the mistake, but rather the guy with lots of time that thinks he is the master of the machine. Don’t let familiarity lull you into complacency thinking you are too experienced to screw up.