Curtiss C-46 N67941 took off from Malmstrom AFB at 14:14 for a flight to Ellsworth AFB. During the climb to altitude, the no. 2 engine overheated. The main-master rod bearing failure forced the crew to shut the engine down a little later. The plane had not obtained sufficient altitude to pass safely over the mountainous terrain, so a turn was made to go back to Malmstrom. The aircraft continued to lose altitude and airspeed, forcing the crew to alter course to fly along a canyon, the floor of which permitted a greater degree of terrain clearance. Once in the canyon however, surrounding terrain soon surmounted the altitude of the aircraft, necessitating the landing on a ploughed field. After touchdown the C-46 struck the earth dam of a small reservoir. PROBABLE CAUSE: “The failure of the captain to effect a proper and timely assessment of a power plant malfunction, followed by improper judgement and technique during a single-engine emergency operation.”