On August 21, 2001, at approximately 0930 mountain daylight time, a Hughes 269C helicopter, N502AA, was substantially damaged when it impacted terrain while maneuvering near Tucumcari, New Mexico. The private pilot and his private pilot passenger were not injured. The T 4 Cattle Co. was operating the helicopter under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local cattle herding flight which had originated from a forward staging area approximately 1 hour before the accident. No flight plan had been filed. The pilot said that he and his son were looking for missing cattle on their ranch. He said that they were flying low on the side of a mesa, over a rough tree covered slope, when the helicopter began losing altitude. The main rotor blades began impacting 10 to 15 foot high cedars, and the helicopter rolled to the right and impacted the ground. The right side of the cockpit was crushed in and the main rotor blades were bent. The pilot reported that the helicopter was powered by a 235 horsepower Lycoming engine. The helicopter's manufacturer records indicated that it was equipped with a Lycoming HIO-360-D1A, which produces 190 horsepower at 4,200 feet (which is the manufacturer's altitude rating). The pilot said that the accident elevation was approximately 4,500 feet, and that the temperature was 96 degrees Fahrenheit; the calculated density altitude was 7,938 feet. A manufacturer's representative calculated the out of ground effect hover capability of the helicopter, with an estimated 1,750 pounds gross weight, was 5,200 feet.