On June 29, 1995, at 0800 central daylight time, a Cessna A188A, N5631J, was substantially damaged during a forced landing following a loss of power during takeoff near Pharr, Texas. The commercial pilot was not injured. Visual meteorological conditions prevailed for the Title 14 CFR Part 137 flight. The aircraft was operated by Holcomb Flying Service, of McAllen, Texas. According to interviews, conducted by a Federal Aviation Administration (FAA) inspector, and in a written report, the pilot stated that during the initial takeoff climb, the engine lost power. The pilot elected to execute a forced landing to a wet cotton field. The right main landing gear separated during the landing roll and the airplane came to rest in the inverted position. Post accident examination of the wreckage revealed that the left wing spar was bent. The operator reported in his written report that the loss of engine power was the result of fuel system contamination. Examination of the engine did not reveal any mechanical anomalies that could have resulted in a loss of engine power. The operator reported in his written report that evidence of fuel contamination was found.