On April 12, 1994, about 1830 hours Mountain standard time, a Bell G-2, N5827U, collided with trees after a loss of engine power while maneuvering over an apple orchard about 19 miles north of Willcox, Arizona. The helicopter was being operated by Arizona Apple Company, Inc., Willcox, Arizona, as a business flight under 14 CFR Part 91. The helicopter was substantially damaged, and the two certificated commercial pilots were not injured. The local flight originated from the operator's facilities 1810 hours. Visual meteorological conditions prevailed at the time. The purpose of the flight was to demonstrate helicopter flying techniques to eradicate frost from the orchard. The pilots reported the helicopter lost power while flying about 15 feet above an apple orchard. The helicopter subsequently settled into trees. Examination of the helicopter's fuel system by an airframe and powerplant mechanic revealed sand-like debris in the fuel samples and the engine carburetor fuel bowl. The mechanic disassembled the carburetor and found the same debris throughout the internal passages.