On June 1, 1999, approximately 1100 mountain daylight time, a Hughes 269A helicopter, N7052L, owned and operated by the pilot, was substantially damaged after colliding with terrain during initial climb following takeoff from a field near Parkman, Wyoming. The airline transport rated pilot, the sole occupant aboard, sustained minor injuries. The aircraft was being operated under Title 14 CFR Part 91, and no flight plan had been filed for the flight to Laurel, Montana. Visual meteorological conditions prevailed. According to the pilot, he departed Laurel at 0900 to check out a camp in the Bighorn National Forest. He stated that he was concerned with the aircraft's performance, but had flown at similar altitudes with cooler temperatures. With his passenger aboard, he performed an out of ground effect hover at 60 feet above ground level (agl). The field's elevation was 7,200 mean sea level (msl). He stated that the aircraft hovered with maximum available power at 2,900 rpm. He entered forward flight and attempted to land in a open field at an elevation of 6,200 feet msl. He aborted his first landing due to downdrafts, and his second attempt was successful. During departure from the field, he elected to perform a practice takeoff without his passenger to test the aircraft's performance. The helicopter flew normally after effective translational lift (ETL) was achieved, and he climbed out at Vy (40 knots), the aircraft's best rate of climb speed. Shortly after clearing a 75-foot ridge 100 to 150 yards from the takeoff field just after coming out of ground effect, the aircraft encountered a downdraft and subsequently began to lose altitude. The power required for the helicopter to climb was greater than the power available. The pilot banked the aircraft to the right to avoid two tall trees. The helicopter impacted the ground through 60 to 80 feet of trees, and came to rest in an inverted position. The pilot stated that there were no mechanical problems, and that the engine was running on impact. The pilot performed an upwind takeoff, and the wind was from 045 degrees at 5 knots, gusting to 15 knots. Density altitude at the time of the accident was calculated to be 7,578 feet. According to calculated weight and performance data, the gross weight of the aircraft at the time of departure was approximately 1,232 lbs. With a maximum takeoff of 2,900 rpm, the maximum available horsepower was 132, and a maximum manifold pressure of 22.2 inches Hg. At an indicated airspeed of 35 knots, the maximum obstacle clearance height was calculated to be 75 feet, with a maximum distance of 800 feet.