On December 18, 2012, about 1449 central daylight time a Beechcraft A23 Musketeer, N3573R, performed a forced-landing after a loss of engine power. The solo student pilot received no injuries. The aircraft received substantial damage to the left wing spar. The aircraft was registered to, and operated by an individual under the provisions of 14 Code of Federal Regulations Part 91 as personal flight. Visual meteorological conditions prevailed for the flight, which operated without a flight plan. The flight originated from Central Nebraska Regional Airport (KGRI) at 1345. While the student pilot was on downwind of his third traffic pattern, during his prelanding checks, the pilot noted that his selected right fuel tank was empty. The pilot then selected the left fuel tank, which indicated 3/8 of a tank of fuel remaining. Approximately four minutes later the airplane lost power and the pilot landed into a field on airport property. The student pilot further stated that immediately after the forced landing, he started the airplane on the ground where the forced landing occurred and taxied back to the ramp with the left tank still selected. A mechanic inspected the engine fuel injection system and found no blockage or contamination in the distribution manifold or the fuel injector nozzles. Lastly, the mechanic drained the remaining fuel from both fuel tanks: The right fuel tank had 1.5 quarts of fuel remaining. The left fuel tank had 19.75 gallons of fuel remaining.