On June 10, 2000, about 1230 Pacific daylight time, a Sikorsky HH-3F, N500XL, collided with trees during a forced landing into a creek bed near Wellington, Nevada. Cinema Aircraft Restorations, LLC, was operating the airplane under the provisions of 14 CFR Part 91. The commercial pilot and one pilot rated passenger sustained serious injuries; the helicopter sustained substantial damage. The personal cross-country flight departed Minden, Nevada, about 1200, en route to Lake Havasu City, Arizona. Visual meteorological conditions prevailed, and no flight plan had been filed. The operator submitted a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2). About 30 minutes into the flight, the pilot noticed a rapid airspeed fluctuation from 80 knots to 20 knots. He completed a systems check and saw the airspeed go to zero. The helicopter rapidly settled. The pilot lowered the collective, but the rpm began to seriously decay. He tried to regain rpm, but was unsuccessful. The helicopter continued to settle downhill into a canyon. The helicopter collided with trees at zero airspeed and 800-feet-per-minute rate of descent in the bottom of the canyon. Federal Aviation Administration inspectors examined the wreckage on scene and interviewed the pilot and passenger. Their investigation disclosed that the helicopter was low and climbing over a ridge in mountainous terrain when it encountered wind shear and could not sustain flight. The helicopter collided with trees when it made the forced landing under power.