On November 12, 1993, about 1015 central standard time, a Bell 47G-3B-1 Soloy, N3078G, collided with trees and the ground, following a loss of engine power during takeoff, near Atmore, Alabama. The helicopter was operated by Louis V. Testa, dba Exploration Helicopters, under 14 CFR Part 133 and visual flight rules. Visual meteorological conditions prevailed. A flight plan was not filed for the external lift flight. There were no injuries to the commercial pilot, and the helicopter was substantially damaged. The flight was originating at the time of the accident. The pilot reported that after lifting seismic equipment with a 100 foot external lift line, about 250 feet above the ground, the engine power decreased. The helicopter is equipped with an Allison 250-C20B turboshaft engine. He released the external load and did not reduce the collective position in an attempt to overfly trees to a road. He was able to reach the road, but collided with trees prior to landing on the road. The rotor speed had decayed and a hard autorotative landing was executed. Examination of the helicopter's fuel supply revealed that it contained water contamination (Record of Telephone Conversation attached). The operator reported that fuel was recently purchased from the Brewton, Alabama, airport. The airport manager, Blayne Kemp, provided a copy of a credit cart receipt for 307.4 gallons of Jet A fuel, purchased by Thunderbird Helicopters, on November 7, 1993. Mr. Kemp stated in a telephone conversation on November 15, 1993, that no water was found in the fuel at the airport. Aircraft records provided by the operator indicated that the helicopter was flown on November 10 and 11. During a telephone conversation with the pilot, he stated that the helicopter was fueled at the remote work site from portable drums that were kept at the site. He also stated that fuel was pumped from the drums into the helicopter without filtration.