Worked with a pilot who took off, minus 1 fuel cap. After an hour or so the engine quit! The pilot then selected the tank with fuel actually in it and failed in his initial attempt to restart the (single) engine. The pilot then reselected the tank (missing the fuel cap) and tried in vain to start the engine all the way to the scene of the accident. The insurance company paid up!!! Some would call this stupid, some illegal - CAR 234.