On December 31, 1998, at 1730 central standard time, a Cessna 152 airplane, N46285, was substantially damaged during a forced landing following a loss of engine power during initial takeoff climb near Bowie, Texas. The flight instructor and the private pilot receiving instruction were not injured. The airplane was owned and operated by Aer Mistral, Inc., of Fort Worth, Texas. Visual meteorological conditions prevailed for the Title 14 CFR Part 91 instructional flight for which a flight plan was not filed. The flight originated from the Meacham International Airport, near Fort Worth, Texas, one hour and 42 minutes prior to the accident. In the enclosed NTSB Form 6120.1/2, the operator reported that the fuel tanks were topped off with 16.9 gallons of 100LL aviation fuel prior to being dispatched to the local training area for an instrument training flight. The flight instructor reported that prior to the accident, he and his student had been executing practice instrument NDB approaches to the Bowie Municipal Airport under their own navigation, while in VFR conditions. The approaches were terminated with touch and go landings. The operator reported that the engine lost power during takeoff from runway 35. He added that the pilot "pitched nose down to avoid a stall." Subsequently, the airplane landed on rough and uneven terrain, nosed over, and came to rest in the inverted position approximately 10 to 15 feet from the west edge of the runway. The flight instructor reported that during initial takeoff climb, he and his student "heard a different engine sound and saw the RPM drop." The flight instructor added that he assumed the controls of the airplane and "put the nose down." As soon as the flight instructor lowered the nose of the airplane, the engine sounded normal again; however, he was too low to recover and the nose landing gear impacted the ground. The airport manager stated that the pilot never reported his position or intentions on the operational Unicom frequency. An eyewitness at the airport reported that the airplane landed hard in "rough and uneven terrain approximately 300 feet to the west of runway 35 abeam the numbers." The witness added that the airplane "did not roll much more than 50 feet before it flipped over on its back. " The 1,800 hour flight instructor and the operator failed to report the mishap to the NTSB or any other agency. The operator recovered the wreckage of the airplane to his maintenance facility in Fort Worth the day after the accident. The flight instructor stated that after his initial examination of the airplane at the accident site, he evaluated the damage incurred to the airplane as "minor." An FAA inspector examined the wreckage at the operator's maintenance facility. His examination confirmed that both wings and the fuselage sustained structural damage. Cylinder compression was checked, and engine continuity was established to the valve train and the accessory case. Electrical continuity to both magnetos was established. Evidence of fuel was found in the carburetor, gascolator, fuel lines, and fuel cells. No pre-existing engine deficiencies were noted and the investigation was not able to determine the reason for the reported loss of engine power. The airport manager reported that the winds at the time of the accident were from the north at 5 to 7 knots.