On January 19, 1996, at 1600 central standard time, a Piper PA- 38-112, N598Z, registered to Avlease, Inc. and operated by Flight Training Systems, Inc., as a 14 CFR Part 91 instructional flight, sustained substantial damage during a forced landing near Falfurrias, Texas. Visual meteorological conditions prevailed and a VFR flight plan was filed. The student pilot was not injured. The flight originated in Brownsville, Texas, approximately 4 hours 30 minutes before the accident. On the enclosed Pilot/Operator Report (NTSB Form 6120.1/2), the pilot stated that he departed Brownsville for Corpus Christi, Texas, to practice "touch and go's." The flight then proceeded to Rockport, Texas, where the pilot executed a full-stop landing. While in Rockport, the fuel tanks were topped off. During the preflight, the pilot "found that both fuel tanks were full" and subsequently, the flight departed to Alice, Texas. The pilot further reported that "I did my preflight again and I found out that there was still enough fuel in both fuel [tanks] to go to Brownsville." The flight departed Alice at 1535 central standard time. Approximately 25 minutes into the return flight, the engine lost power and the "fuel pressure needle dropped to the red line." Emergency procedures by the pilot did not restore engine power. Subsequently, the pilot executed a forced landing to a field with soft soil. Examination of the airplane by the FAA inspector and the operator's mechanic revealed that the left fuel tank was empty, the gascolator did not contain fuel, and the right fuel tank was full. The FAA inspector reported that the fuel selector was on the left tank. Structural damage occurred to the right wing, and fuselage.