On August 12, 1998, at about 1145 eastern daylight time, a Enstrom F-28F, N19BZ, registered to a private owner, operating as a 14 CFR Part 91 sightseeing flight, crashed in the vicinity of Marco Island, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The helicopter sustained substantial damage. The commercial pilot and two passengers reported no injuries. The flight originated from Marco Island, Florida, about 30 minutes before the accident. The pilot stated he was in cruise flight when he experienced a total loss of engine power. He lowered the collective pitch, entered autorotation, and made a right, 100 degree turn towards a dirt road. At 100 feet he started a flare and applied collective cushioning pitch late. The helicopter touched down right skid low. The main rotor blade flexed down, and collided with the tailboom assembly. Examination of the crash site revealed the helicopter was partially resting on its belly due to the collapse of the right hand skid cross tube, and the tailboom had been severed. Visual examination of the fuel tanks revealed little or no fuel. Fuel was added to both fuel tanks after the helicopter was transported to an authorized repair facility. The engine was started and was run for about 5 minutes. The pilot informed the FAA that he made a hard landing during the autorotation resulting in damage to the helicopter.