At 16:28 CDT, a Piper Seneca was damaged during a forced landing near Laredo. The pilot and two passengers were not injured. The flight originated in San Antonio, at which time the right fuel gauge indicated 35 gallons and the left tank indicated somewhat higher, according to the pilot. Approximately 40 minutes into the flight the ammeter began indicating a failure, so the pilot turned off unnecessary electrical equipment. He then saw the left fuel gauge go from eight gallons indicated to zero and the right gauge go from 20 gallons indicated to zero. Subsequently both engines lost power. He set up to land on a road, but traffic forced him to land adjacent to the road and the right wing struck a fence. An investigation showed the aircraft contained no usable fuel.