On January 9, 1998, at 1245 central standard time, a Cessna 152, N757CH, impacted terrain during a forced landing following a loss of engine power near Boyd, Texas. The airplane was operated by Bourn Ammenson Aviation, Inc., Fort Worth, Texas, under Title 14 CFR Part 91. The private pilot/instrument student and the commercial pilot/flight instructor received minor injuries, and the airplane sustained substantial damage. Visual meteorological conditions prevailed and a flight plan was not filed for the local instructional flight that departed Hicks Airfield at 1230. During personal interviews, conducted by the investigator-in-charge, and on the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the flight instructor and instrument student reported that the student was practicing standard rate (500 fpm) descents and climbs. The flight descended with the power at 2,000 RPM from 3,000 feet MSL to 1,500 feet MSL, and the instrument student applied full throttle for the climb; however, the engine power did not increase. The flight instructor took the flight controls and applied carburetor heat and performed the emergency checklist; however, the power decreased through 1,500 RPM to 1,200 RPM. At a descent rate of 200 fpm, the flight instructor selected a field which "appeared to be suitable for the landing." However, the field was rough and the airplane struck the ground and again became airborne. The flight instructor, observing a powerline and fence ahead of the airplane, flew the airplane under the powerline and over the fence. Subsequently, the airplane "stalled" as it approached a hill. The left wing and the nose gear struck the ground, and the airplane came to rest inverted. The left wing, vertical stabilizer, and rudder sustained damage. The flight instructor reported the temperature at 55 degrees Fahrenheit with a dew point of 40 degrees Fahrenheit. The National Weather Service (METAR) observation at 1253 for the Alliance Airport (14 miles east of the accident site) reported the temperature at 46.4 degrees Fahrenheit with a dew point of 39.2 degrees Fahrenheit and a relative humidity of 61 per cent. The icing probability curves showed the conditions to be favorable for serious carburetor icing.