This is a perfect example of the swiss-cheese model of accident causation. If any of the following were different there would not have been an issue: the fuel g

This is a perfect example of the swiss-cheese model of accident causation. If any of the following were different there would not have been an issue: the fuel gauge was working, the pilot or co-pilot caught the fueling error, or the aircraft was grounded due to the fuel gauge being inoperative.